Patent Publication Number: US-2020301266-A1

Title: Light source device, image projection apparatus, light source optical system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2019-052670, filed on Mar. 20, 2019 and Japanese Patent Application No. 2019-217929, filed on Dec. 2, 2019 in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a light source device, an image projection apparatus, and a light source optical system. 
     Related Art 
     Projectors (image projection apparatuses) that magnify and project various images are widely used. A projector focuses light emitted by a light source onto a spatial light modulation element, such as a digital micromirror device (DMD) or a liquid crystal display element, and displays, as a color image, light modulated in accordance with an image signal and emitted from the spatial light modulation element onto a screen. 
     A projector in many cases uses, for example, a high-brightness extra-high-pressure mercury lamp in related art. However, the life of such a lamp is short and the maintenance is frequently required. Owing to this, the number of projectors provided with, for example, laser sources or light emitting diodes (LEDs) instead of extra-high-pressure mercury lamps is growing. This is because a laser source and an LED have longer lives and higher color reproducibility due to monochromaticity compared to an extra-high-pressure mercury lamp. 
     A projector irradiates an image display element such as a DMD with light of, for example, three colors including red, green, and blue which are primary colors to form an image. All the three colors can be generated by laser sources; however, this is not desirable because a green laser and a red laser have lower emission efficiencies than a blue laser. Thus, there is used a method of irradiating a fluorescent material with a blue laser beam as excitation light to obtain fluorescence (fluorescence light) through wavelength conversion at the fluorescent material and generating red light and green light from the fluorescence. 
     Since excitation light of several tens of watts (W) is condensed and emitted to the fluorescent material, the efficiency degradation or the changes over time might occur due to burnout or temperature rise. For this reason, the phosphor (fluorescent material) layer is formed on the disk and rotated to prevent the irradiation position of the excitation light from being concentrated on one point. The disk is called a phosphor wheel. In the phosphor wheel, the fluorescent material is formed in a fan shape or a toroidal shape along the periphery of the disk. 
     SUMMARY 
     In one aspect of this disclosure, there is provided an improved light-source device including: an excitation light source configured to emit first colored light; an optical element having a reflecting surface to reflect the first colored light emitted from the excitation light source; and a wavelength conversion unit configured to emit the first colored light reflected by the optical element. The wavelength conversion includes a waveform conversion member configured to convert at least a portion of the first colored light reflected by the optical element and incident on the wavelength conversion unit, into second colored light having a wavelength different from a wavelength of the first colored light and emit the second colored light. A point P does not intersect with a light flux Q where the point P is a center of the first colored light on the reflecting surface of the optical element and the light flux Q is a light flux of the first colored light emitted from the wavelength conversion unit. 
     In another aspect of this disclosure, there is provided an improved image projection apparatus including the above-described light-source device; an image display element configured to generate an image of light emitted from the light-source device; an illumination optical system configured to guide the light emitted from the light-source device to the image display element; and a projection optical system configured to project the image generated by the image display element. 
     In even another aspect of this disclosure, there is provided an improved light source optical system including an optical element having a reflecting surface to reflect first colored light emitted from an excitation light source; and a wavelength conversion unit configured to emit the first colored light reflected by the optical element. The wavelength conversion unit includes a waveform conversion member configured to convert at least a portion of the first colored light reflected by the optical element and incident on the wavelength conversion unit, into second colored light having a wavelength different from a wavelength of the first colored light and emit the second colored light. A point P does not intersect with a light flux Q where the point P is a center of the first colored light on the reflecting surface of the optical element and the light flux Q is a light flux of the first colored light emitted from the wavelength conversion unit. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The aforementioned and other aspects, features, and advantages of the present disclosure would be better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIGS. 1A and 1B  are schematic diagrams of a light-source device according to an embodiment of the present disclosure; 
         FIG. 2  is a schematic diagram of the light-source device according an embodiment of the present disclosure; 
         FIG. 3  is a schematic diagram of the light-source device according to an embodiment of the present disclosure; 
         FIG. 4  is a schematic diagram of the light-source device according to an embodiment of the present disclosure; 
         FIGS. 5A, 5B, and 5C  are schematic diagrams of the light-source device according to an embodiment of the present disclosure; 
         FIGS. 6A and 6B  are schematic diagrams of the light-source device according to an embodiment of the present disclosure; 
         FIGS. 7A and 7B  are schematic diagrams of the light-source device according to an embodiment of the present disclosure; 
         FIG. 8  is a schematic diagram for describing the optical properties of the rod integrator in the light-source device according to an embodiment of the present disclosure; 
         FIG. 9  is a schematic diagram for describing the optical properties of the rod integrator in the light-source device according to another embodiment of the present disclosure; 
         FIG. 10  is a schematic diagram of a projector provided with a light-source device according to a first embodiment; 
         FIGS. 11A and 11B  are schematic views of the light-source device according to the first embodiment; 
         FIG. 12  is an illustration of the outline of a light source unit included in the light-source device according to the first embodiment; 
         FIG. 13  is an illustration of an example of the dichroic mirror of the light-source device according to the first embodiment; 
         FIGS. 14A and 14B  are illustrations of a configuration of a phosphor unit in the light-source device according to the first embodiment; 
         FIGS. 15A and 15B  are illustrations of a configuration of a color wheel in the light-source device according to the first embodiment; 
         FIGS. 16A and 16B  are illustrations of an incident aperture of a light tunnel in the light-source device according to the first embodiment, as viewed from the incident direction of light; 
         FIGS. 17A and 17B  are schematic views of a configuration of a light-source device according to a second embodiment; 
         FIG. 18  is an illustration of an example of a configuration of a dichroic mirror in the light-source device according to the second embodiment; 
         FIGS. 19A and 19B  are schematic views of a light-source device according to a third embodiment; 
         FIGS. 20A and 20B  are schematic views of a light-source device according to the fourth embodiment; 
         FIG. 21  is a schematic diagram of a phosphor unit in a light-source device according to a fourth embodiment; 
         FIGS. 22A and 22B  are schematic diagrams of a light-source device according to a fifth embodiment; 
         FIGS. 23A and 23B  are schematic diagram of a light-source device according to a sixth embodiment; 
         FIGS. 24A and 24B  are schematic diagrams of a light-source device according to a seventh embodiment of the present disclosure; and 
         FIGS. 25A and 25B  are schematic diagrams of a light-source device according to an eighth embodiment. 
     
    
    
     The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. 
     DETAILED DESCRIPTION 
     In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner and achieve similar results. 
     Although the embodiments are described with technical limitations with reference to the attached drawings, such description is not intended to limit the scope of the disclosure and all of the components or elements described in the embodiments of this disclosure are not necessarily indispensable. 
     Referring now to the drawings, embodiments of the present disclosure are described below. In the drawings for explaining the following embodiments, the same reference codes are allocated to elements (members or components) having the same function or shape and redundant descriptions thereof are omitted below. 
     Conventionally, light-source devices are known provided with a DMD and a phosphor wheel whose part is used as a reflector so as to reduce the size of the entire light-source device. In such light-source devices, the excitation light is reflected by the phosphor wheel in the same direction as the fluorescent light, and the reflected light is prevented from returning to the excitation light source by using a phase-contrast plate (quarter (¼) wave retarder) and the polarization splitter. 
     In the light-source device having such a configuration, the phase-contrast plate (quarter-wave retarder) and the polarization splitter are disposed. This restricts a reduction in the size of the light-source device and also increases the cost. In addition, the optical path of the excitation light proceeding to the phosphor wheel and the optical path of the excitation light reflected from the phosphor wheel pass through the same position in phase-contrast plate or the polarization splitter. For this reason, the light condensing density on these optical elements might increase, and this might cause damage or the like, thus resulting in a decrease in reliability. 
     The present inventors have paid attention to the fact that such a configuration of the light-source device hampers the downsizing of the device body and the reduction in cost, and also causes a decrease in reliability. Then, the present inventors have conceived of the embodiments of the present disclosure that achieve a reduction in the size of the device body and the cost and an increase in reliability by preventing the optical path of the excitation light proceeding to the phosphor wheel and the optical path of the excitation light reflected from the phosphor wheel from overlapping with each other. 
     In other words, the embodiments of the present disclosure provide a light-source device including a light source that emits excitation light, an optical element having a reflecting surface that reflects the excitation light emitted from the light source, and a wavelength conversion unit including a wavelength conversion member configured to convert at least some of the excitation light into a fluorescence having a wavelength different from a wavelength of the excitation light and emit the converted fluorescence. In such a light-source device, a point P is prevented from intersecting with a light flux Q where the point P is the center of a projection image of the excitation light projected onto the reflecting surface of the optical element, and the light flux Q is a light flux of excitation light emitted from the wavelength conversion unit. 
     According to the embodiments, the light flux of the excitation light emitted from the wavelength conversion unit does not intersect with the center of the projection image of the excitation light emitted from the light source. This prevents these pieces of excitation light from passing through the same location on the optical element, which further prevents damage of the optical element due to an increase in the light condensing density. Thus, the reliability can be increased. Further, in the present embodiment, particular optical elements such as a phase-contrast plate and a polarization splitter are not used to separate the optical paths of the excitation light from each other. This reduces the number of components and the cost for producing the device, thus achieving a reduction in the size of the device. 
       FIGS. 1A and 1B  are schematic diagrams of a light-source device  100  according to an embodiment of the present disclosure.  FIG. 1A  is an illustration of the components of the light-source device  100  according to an embodiment.  FIG. 1B  is an illustration of excitation light projected onto a reflecting surface  102   a  of a dichroic mirror  102  of the light-source device  100 .  FIG. 1B  indicates the reflecting surface  102   a  as viewed from the direction of travel of the excitation light from the light source  101 . 
     As illustrated in  FIGS. 1A and 1B , the light-source device  100  according to an embodiment includes a light source (an excitation light source)  101 , a dichroic mirror  102  constituting an example of an optical element, a phosphor unit  103  constituting an example of a wavelength conversion unit, and a rod integrator  104  constituting an example of a light mixing device. 
     The configuration of the light-source device  100  according to the present embodiments is not limited to the configuration illustrated in  FIG. 1  and can be appropriately changed. For example, the light-source device  100  may be equipped with the light source  101 , the dichroic mirror  102 , and the phosphor unit  103  only. In the light-source device  100  equipped with the light source  101 , the dichroic mirror  102 , and the phosphor unit  103 , the components other than the light source  101  constitute a light-source optical system. 
     The light source  101  emits excitation light (first colored light). The dichroic mirror  102  has a reflecting surface  102   a  that reflects the excitation light emitted from the light source  101  and guides the excitation light to the phosphor unit  103 . The portion of the dichroic mirror  102  other than the reflecting surface  102   a  may have an optical property that transmits the excitation light emitted from the light source  101  and the fluorescence light emitted from the phosphor unit  103 . 
     The phosphor unit  103  has a first area that reflects or diffuse-reflects the excitation light and a second area that converts at least a part of the excitation light into fluorescence (fluorescence light) (second colored light) having a wavelength different from the wavelength of the excitation light and emits the fluorescence. Once the excitation light is incident on the phosphor unit  103 , the phosphor unit  103  alternately emits the excitation light and the fluorescence (fluorescence light) to the incident-plane side (upward in  FIG. 1A ) on which the excitation light from the light source  101  has been incident, in a sequential manner. The rod integrator  104  is disposed such that the excitation light and the fluorescence emitted from the phosphor unit  103  are directed to and incident on the rod integrator  104 . The rod integrator  104  mixes (homogenizes) the incident excitation light and fluorescence to emit the mixed light to the outside of the light-source device  100 . 
       FIG. 1A  indicates a case in which the first area of the phosphor unit  103  is provided in the optical path of the excitation light emitted from the light source  101 . The excitation light emitted from the light source  101  is reflected by the reflecting surface  102   a  of the dichroic mirror  102  toward the phosphor unit  103  side. The excitation light reflected by the reflecting surface  102   a  is reflected by the first area of the phosphor unit  103  toward the incident-plane side on which the reflected excitation light has been incident on the phosphor unit  103 . The rod integrator  104  is arranged ahead in the direction of the reflection of the excitation light from the phosphor unit  103 . 
     In the light-source device  100  with the above-described arrangement of the optical path of the excitation light, the center of the excitation light on the reflecting surface  102   a  of the dichroic mirror  102  is defined as a point P, and the light flux of the excitation light emitted from the phosphor unit  103  is defined as a light flux Q. In the light-source device  100 , the dichroic mirror  102 , the phosphor unit  103 , and the rod integrator  104  are arranged so that the point P and the light beam Q do not intersect with each other. 
     The point P of the excitation light (the center of the projection image of the excitation light projected onto the reflecting surface  102   a ) is defined as follows: (1) When the light intensity distribution within the projection range of the excitation light projected onto the reflecting surface  102   a  is line-symmetric or point-symmetric, the center of the minimum circumscribed circle (circumcircle) of the projection range of the excitation light is set as the center of the projection image center. (2) When the light intensity distribution in the projection range of the excitation light projected on the reflecting surface  102   a  is a pattern other than the line symmetry or the point symmetry (that is, any case other than the case (1) above), the center P is defined as follows: As illustrated in  FIG. 1B , when A denotes the total energy of the excitation light projected onto the reflecting surface  102   a  and B denotes the total energy of light included in any desired circle with a radius r within the projection range, the ratio of B with respect to A (B/A) is greater than or equal to 93% (B/A≥93%) and the center of the circle with a radius r, at which the energy density is maximum within the circle, is set as the center of the projection image. 
     Note that the projection range of the excitation light is a range having an energy of 1/e 2  or more of the maximum energy within the energy distribution of the excitation light projected onto the reflecting surface  102   a . The energy density is obtained by dividing the energy included in the circle by the dimension of the circle. In other words, the energy density is obtained by the following equation: 
       Energy Density=(Energy included in Circle)/(Dimension of Circle) 
     Note that the center (the point P) of the projection image of the excitation light as defined above is determined with all the light source  101  within the light-source device  100  turned on. 
     Further, the light flux (light flux Q) of the excitation light emitted from the phosphor unit  103  is a light flux of light rays passing through the range having the energy of 1/e 2  or more of the maximum energy within the energy distribution of the excitation light on a plane perpendicular to the propagation direction of the excitation light. 
     In the light-source device  100  according to an embodiment, the light flux Q of the excitation light emitted from the phosphor unit  103  is prevented from intersecting with the center (the point P, i.e., the center of the projection image of the excitation light) of the excitation light emitted from the light source  101  and projected on the reflecting surface  102   a . This configuration prevents both the excitation light projected on the reflecting surface  102   a  and the excitation light emitted from the phosphor unit  103 , from passing through the same location on the dichroic mirror  102 . Thus, the dichroic mirror  102  is prevented from being damaged due to an increase in the light condensing density. Further, in the present embodiment, particular optical elements such as a phase-contrast plate and a polarization splitter are not used to separate the optical path of the excitation light emitted from the phosphor unit  103 , from the other optical path. This configuration reduces the number of components and the cost for producing the device, thus achieving a reduction in the size of the device. 
     In the light-source device  100  illustrated in  FIGS. 1A and 1B , the phosphor unit  103  alternately emits the excitation light and the fluorescence in a sequential manner. In other words, the case in which the phosphor unit  103  emits the excitation light and the fluorescence in a time-division manner is described. However, the configuration of the phosphor unit  103  is not limited thereto, and the phosphor unit  103  may be configured to emit excitation light and fluorescence simultaneously. 
     For example, instead of the first and second area, the phosphor unit  103  has an area (a third area) that reflects a portion of the excitation light and converts the other portion of the excitation light into a fluorescence having a waveform different from a waveform of the excitation light. For example, the wavelength conversion member provided in the third area serves to perform the reflection of the excitation light and the conversion into the fluorescence. The phosphor unit  103  is sometimes referred to as a stationary phosphor unit. Once the excitation light is incident on the phosphor unit  103 , the phosphor unit  103  emits the excitation light and the fluorescence together to the incident-plane side (upward in  FIG. 1A ) on which the excitation light has been incident on the phosphor unit. In the configuration provided with such a phosphor unit  103  having the third area as well, the same advantageous effect can be exhibited as in the case in which the phosphor unit  103  operates in a time-division manner. 
     In some examples, the light-source device  100  in  FIG. 1  may include a light guide configured to guide at least one of the excitation light and the fluorescence emitted from the phosphor unit  103  to the rod integrator  104 . For example, the light guide includes a condenser lens and a constituted by a condenser lens or a refractive lens (refractor), and is arranged in an optical path between the phosphor unit  103  and the rod integrator  104 . With the provision of the light guide, at least one of the excitation light and the second colored light emitted from the phosphor unit  103  is effectively guided to the rod integrator  104 , and the utilization efficiency of light can be improved. 
     Further, in the light-source device  100  according to an embodiment, the position of the rod integrator  104  may be changed where appropriate from the viewpoint of improving the utilization efficiency of at least one of the excitation light and the fluorescence incident on the rod integrator  104 .  FIG. 2  is a schematic diagram of the light-source device  100  according another embodiment of the present disclosure. In  FIG. 2 , the same reference numerals are given to the same components as those in  FIG. 1 , and the description thereof will be omitted. In the light-source device illustrated in  FIG. 2 , the reflecting surface  102   a  is formed over the surface of the dichroic mirror  102 . The same applies to the figures to be described below. 
     In the embodiment illustrated in  FIG. 2 , the center of the projection image of excitation light emitted from the dichroic mirror  102  and projected onto the phosphor unit  103  is designated as a point R. In this case, it is preferably that the rod integrator  104  is disposed on the normal to the point R on the exit plane  103   a  of the phosphor unit  103 . With such an arrangement of the rod integrator  104 , the fluorescence, which is emitted from the exit plane  103   a  of the phosphor unit  103 , can be incident on the rod integrator  104  effectively. Thus, the utilization efficiency of the fluorescence can be improved. 
     In some examples, a focusing element may be provided between the dichroic mirror  102  and the phosphor unit  103  in the light-source device  100  according to an embodiment of the present disclosure. Such a focusing element serves to converge the excitation light reflected by the dichroic mirror  102  and substantially collimates the fluorescence emitted from the phosphor unit  103 . For example, the focusing element is a condenser lens.  FIG. 3  is a schematic diagram of the light-source device  100  according to an embodiment of the present disclosure. In  FIG. 3 , the same reference numerals are given to the same components as those in  FIG. 1 , and the description thereof will be omitted. 
     In the light-source device  100  illustrated in  FIG. 3 , a condenser lens  105  as the focusing element is disposed in the optical path between the dichroic mirror  102  and the phosphor unit  103 . The condenser lens  105  serves to converge the excitation light reflected by the dichroic mirror  102  and substantially collimate the fluorescence emitted from the phosphor unit  103 . 
       FIG. 3  indicates a straight line L 1  connecting the above-described point P on the reflecting surface  102   a  and the center of the projection image on an incident plane  105   a  of the condenser lens  105 , the projection image being formed by the excitation light that has been reflected by the reflecting surface  102   a  of the dichroic mirror  102  and incident on the condenser lens  105 . Further,  FIG. 3  also indicates a point S that is a point of intersection of the straight line L 1  and an incident plane  103   b  of the phosphor unit  103  on which the excitation light that has been condensed by the condenser lens  105  is incident. In the light-source device  100 , the above-described point S is located at a different position from a point R that is the center of the projection image of the excitation light projected onto the phosphor unit  103 . With such an arrangement of the condenser lens  105 , the excitation light and the fluorescence, which are to be emitted from the phosphor unit  103  while diverging, can be collimated. Accordingly, the collimated excitation light and fluorescence can be incident on the rod integrator  104  effectively, thus improving the utilization efficiency of light. 
     In the light-source device  100  illustrated in  FIG. 3 , it is desired that the above-described straight line L 1  intersect perpendicularly with the incident plane  103   b  of the phosphor unit  103 . With such a configuration that the straight line L 1  intersects perpendicularly with the incident plane  103   b  of the phosphor unit  103 , the distance between the dichroic mirror  102  and the phosphor unit  103  can be reduced, and the size of the entire light-source device  100  can be reduced. 
     In the case where light passes through an optical element having a certain thickness, the incident plane is a surface on which the light is incident, and the exit plane is a surface from which the light is emitted. For example, in the condenser lens  105  as illustrated in  FIG. 3 , the incident plane  105   a  is a surface that light reflected by the reflecting surface  102   a  of the dichroic mirror  102  is incident on, and the exit plane  105   b  is a surface from which the light that has been incident on the incident plane  105   a  and passed through the condenser lens  105  is emitted toward the phosphor unit  103  side. 
     In some other examples, a refractive optical element may be disposed in the optical path between the condenser lens  105  and the rod integrator  104 . Such a refractive optical element serves to converge the excitation light and/or fluorescence collimated by the focusing element (the condenser lens  105 ) and guide the converged excitation light and fluorescence to the rod integrator  104 . For example, the refractive optical element is a refractive lens.  FIG. 4  is a schematic diagram of the light-source device  100  according to an embodiment of the present disclosure. In  FIG. 4 , the same reference numerals are given to the same components as those in  FIG. 3 , and the description thereof will be omitted. 
     In the light-source device  100  illustrated in  FIG. 4 , a refractive lens  106  as the refractive optical element is disposed in the optical path between the condenser lens  105  and the rod integrator  104 . The refractive lens  106  serves to condense (refract) the excitation light and/or the fluorescence, which are collimated by the focusing element (condenser lens  105 ) and guide the converged excitation light and fluorescence light to an incident aperture  104   a  of the rod integrator  104 . With such an arrangement of the refractive lens  106 , the excitation light and/or fluorescence collimated by the condenser lens  105  can be efficiently incident on the rod integrator  104 , thus improving the utilization efficiency of light. 
     In the light-source device  100  illustrated in  FIG. 4 , it is desired that the rod integrator  104  be disposed so as to homogenize the excitation light and/or fluorescence to be incident on the rod integrator  104 . More specifically, when the inner surface cross section of the rod integrator  104  is rectangular, preferably, the rod integrator  104  is disposed so that the excitation light or the like to be incident on the rod integrator  104  is incident on the longer side of the inner surface of the rod integrator  104 . 
     Further, in the light-source device  100  in  FIG. 4 , it is desired that the light source  101  be disposed to substantially prevent vignetting of the excitation light on the reflecting surface  102   a  of the dichroic mirror  102 . More specifically, when the light-emitting surface of the light source  101  is rectangular, preferably, the light source  101  is disposed such that the width of the excitation light is narrower. 
       FIGS. 5A, 5B, and 5C  are schematic diagrams of the light-source device  100  according to an embodiment. In  FIG. 5 , the same reference numerals are given to the same components as those in  FIG. 4 , and the description thereof will be omitted.  FIG. 5A  is an illustration of the constituent elements of the light-source device  100  according to the present embodiment.  FIG. 5B  is an illustration of the incident aperture  104   a  of the rod integrator  104  of the light-source device  100 .  FIG. 5C  is an illustration of the light source  101  of the light-source device  100 .  FIG. 5B  indicates the incident aperture  104   a  of the rod integrator  104  as viewed from the phosphor unit  103  side.  FIG. 5C  indicates the light-emitting surface of the light source  101  as viewed from the dichroic mirror  102  side. 
     In the light-source device  100  illustrated in  FIG. 5A , a point T is the center of the projection image projected on the incident aperture  104   a  of the rod integrator  104 , the projection image being formed by the excitation light and/or the fluorescence condensed (refracted) by the refractive lens  106 . Further, a straight line L 2  is a straight line connecting the point T and a certain point R that is the center of the projection image of the excitation light projected on the phosphor unit  103 . As illustrated in  FIG. 5B , the incident aperture  104   a  of the rod integrator  104  has a rectangular shape having a longer side LE 1  and a shorter side SE 1 . Further, as illustrated in  FIG. 5C , the light-emitting surface  101   a  of the light source  101  has a rectangular shape having a longer side LE 2  and a shorter side SE 2 . 
     In the light-source device  100 , preferably, a plane (a plane including the drawing sheet in which  FIG. 5A  is drawn) including the straight line L 1  and the straight line L 2  is substantially parallel to the shorter side SE 1  of the incident aperture  104   a  of the rod integrator  104 . In other words, the rod integrator  104  is arranged such that the shorter side SE 1  of the rod integrator  104  in  FIG. 5B  is parallel to the drawing sheet of  FIG. 5A . With such an arrangement of the rod integrator  104 , the excitation light can strike on the inner surface corresponding to the longer side LE 1  of the incident aperture  104   a  of the rod integrator  104  so as to be incident on the rod integrator  104 . Accordingly, the number of reflection of the excitation light or the like within the rod integrator  104  is increased, and the excitation light or the like is homogenized, thus preventing unevenness in the color of the excitation light or the like. 
     In the light-source device  100 , preferably, the plane including the straight line L 1  and straight line L 2  (the plane including the drawing sheet in which  FIG. 5A  is drawn) is substantially parallel to the shorter side SE 2  of the light-emitting surface  101   a  of the light source  101 . In other words, the light source  101  is arranged such that the shorter side SE 2  of the light-emitting surface  101   a  in  FIG. 5C  is parallel to the drawing sheet of  FIG. 5A . With such an arrangement of the light source  101 , the width of the light flux extending in a direction in which the plane including the straight lines L 1  and L 2  extends can be reduced. This prevents vignetting on the reflecting surface  102   a  of the dichroic mirror  102 , and the reduction in the utilization efficiency of light can be prevented. Further, the light reflected by the phosphor unit  103  can be prevented from interfering with the dichroic mirror  102 , and the reduction in the utilization efficiency of light can be prevented as well. 
     Further, in the light-source device  100  according to an embodiment of the present disclosure, the rod integrator  104  is disposed so that an angle formed by the incident aperture  104   a  and the incident plane on which the excitation light is incident to enter the rod integrator  104  is set within a certain range. For example, in the light-source device  100 , the rod integrator  104  is preferably arranged so that the angle formed by the incident aperture  104   a  and the incident plane on which the excitation light is incident to enter the rod integrator  104  is smaller than a certain angle. 
       FIGS. 6A and 6B  are schematic diagrams of the light-source device  100  according to an embodiment of the present disclosure. In  FIGS. 6A and 6B , the same components as those in  FIG. 5A  are denoted by the same reference numerals, and description thereof will be omitted.  FIG. 6A  is an illustration of the constituent elements of the light-source device  100  according to the present embodiment.  FIG. 6B  is an illustration of the incident plane of the excitation light to be incident on the incident aperture  104   a  of the rod integrator  104  included in the light-source device  100 .  FIG. 6A  indicates the optical path of the excitation light in the light-source device  100 . 
     In the light-source device  100  illustrated in  FIG. 6A , the excitation light EL (incident light) is light that is condensed by the refractive lens  106  and incident on the incident aperture  104   a . In the light-source device  100 , the rod integrator  104  is arranged so that the angle formed by the incident aperture  104   a  and the incident plane of the excitation light EL to be incident on the incident aperture  104   a  is smaller than 40°. 
     In the present disclosure, the incident plane is defined as a plane including a normal line of a target surface (a certain surface), on which a certain light ray is incident, and the light ray incident on the target surface. When the plane constituting the incident aperture  104   a  is the target surface, the incident plane of the excitation light (incident light) EL incident on the incident aperture  104   a  is a plane EF including the excitation light EL and a normal line  104   a L of the incident aperture  104   a  as illustrated in  FIG. 6B . 
     In the light-source device  100  illustrated in  FIG. 6A , the rod integrator  104  is disposed so that an angle β between the incident aperture  104   a  and the incident plane EF of the excitation light (incident light) EL incident on the incident aperture  104   a  is smaller than 40°. With such an arrangement of the rod integrator  104 , the excitation light is prevented from being obliquely incident on the rod integrator  104 . Accordingly, the excitation light can be sufficiently mixed inside the rod integrator  104 , and the unevenness in color can be substantially prevented. As a result, the utilization efficiency of light is improved. 
     Further, in the light-source device  100  according to an embodiment of the present disclosure, it is desired that the rod integrator  104  be disposed according to the relative position of the refractive lens  106  and the rod integrator  104 . For example, in the light-source device  100  according to the present embodiment, the center of the projection image of the excitation light projected onto the incident aperture  104   a  of the rod integrator  104 , the center of the fluorescence projected onto the incident aperture  104   a  of the rod integrator  104 , and the optical axis of the refractive lens  106  intersect at one point. 
       FIGS. 7A and 7B  are schematic diagrams of the light-source device  100  according to an embodiment of the present disclosure. In  FIGS. 7A and 7B , the same components as those in  FIG. 5A  are denoted by the same reference numerals, and description thereof will be omitted.  FIG. 7A  indicates the optical path of the excitation light in the light-source device  100 , and  FIG. 7B  indicates the optical path of the fluorescence in the light-source device  100 .  FIGS. 7A and 7B  also indicate a pair of condenser lenses  1051  and  1052  arranged along the propagation direction of light. 
     In the light-source device  100  illustrated in  FIGS. 7A and 7B , both the center of the projection image on the incident aperture  104   a  of the rod integrator  104 , the projection image being formed by the excitation light converged by the refractive lens  106 , and the center of the projection image on the incident aperture  104   a  of the rod integrator  104 , the projection image being formed by the fluorescence converged by the refractive lens  106  are the above-described point T. Further, the refractive lens  106  is arranged so that the optical axis LA of the refractive lens  106  passes through the point T. For this reason, the center of the projection image of the excitation light projected onto the incident aperture  104   a  of the rod integrator  104 , the center of the projection image of the fluorescence projected onto the incident aperture  104   a  of the rod integrator  104 , and the optical axis LA of the refractive lens  106  intersect at one point. This arrangement enables the excitation light and the fluorescence to be incident on the center of the incident aperture  104   a  of the rod integrator  104 , and thus substantially prevents the occurrence of the vignetting on the incident aperture  104   a  of the rod integrator  104 . As a result, the utilization efficiency of light can be improved. In addition, a reduction in the utilization efficiency of light, caused by misalignment of the optical elements within the light-source device  100  due to component tolerances, can also be substantially prevented. 
     Further, in the light-source device  100  according to the present embodiment, the refractive lens  106  is arranged so that the angle at which each of the excitation light and the fluorescence (fluorescence light) is incident on the incident aperture  104   a  of the rod integrator  104  is set within a certain range. Note that the angle of the light ray with respect to the incident aperture  104   a  refers to an angle between the light ray and the normal line of a plane parallel to the incident aperture  104   a . For example, in the light-source device  100 , the maximum incident angle of a light ray of the excitation light with respect to the incident aperture  104   a  is smaller than the maximum incident angle of a light ray of the fluorescence with respect to the incident aperture  104   a.    
     As illustrated in  FIGS. 7A and 7B , an angle θ 1  is the maximum incident angle of the light ray of the excitation light with respect to the incident aperture  104   a , and an angle θ 2  is the maximum incident angle of the light ray of the fluorescence with respect to the incident aperture  104   a . In the light-source device  100 , it is desired that the angle θ 1  be set smaller than the angle θ 2 . By making the incident angle θ 1  of the excitation light smaller than the incident angle θ 2  of the fluorescence, the occurrence of vignetting in an optical system arranged downstream of the light-source device  100  is substantially prevented, and thus the utilization efficiency of light is improved. 
     In the light-source device  100  according to an embodiment of the present disclosure, the incident angle θ 1  of the excitation light and the incident angle θ 2  of the fluorescence may be set equal to each other. By making the incident angle θ 1  of the excitation light equal to the incident angle θ 2  of the fluorescence, the distribution of the excitation light projected on the DMD or the screen is made substantially the same as the distribution of the fluorescence projected on the DMD or the screen. Accordingly, the unevenness in the color of the excitation light or the like can be substantially prevented. 
     Further, in the light-source device  100  according to the present embodiment, the optical properties of the rod integrator  104  may be selected according to the relation of the incident angle θ 1  of the excitation light and the incident angle θ 2  of the fluorescence. For example, in the light-source device  100 , the rod integrator  104  is formed of a glass rod integrator, and the total reflection condition of the glass rod integrator is set to be larger than the incident angle θ 1  of the excitation light and the incident angle θ 2  of the second colored light. 
       FIG. 8  is a schematic diagram for describing the optical properties of the rod integrator  104  in the light-source device  100  according to an embodiment of the present disclosure. In the light-source device  100  illustrated in  FIG. 8 , the rod integrator  104  is formed of a glass rod integrator. The total reflection condition in the rod integrator  104  is assumed to be an angle θ glass . In this case, the angle θ glass  is set to be larger than the incident angle θ 1  of the excitation light and the incident angle θ 2  of the fluorescence. With such a configuration, loss of the excitation light and the like inside the rod integrator  104  is prevented, and thus the utilization efficiency of light is improved. 
       FIG. 9  is also a schematic view for describing the optical properties of the rod integrator  104  included in the light-source device  100  according to another embodiment of the present disclosure. In the light-source device  100  in  FIG. 9 , the rod integrator  104 , which constitutes a light mixing device, has a tapered shape in which the incident aperture  104   a  is smaller than an exit aperture  104   b . With such a tapered shape of the rod integrator  104 , the exit angle at which light exits the rod integrator  104  can be made small. Accordingly, the occurrence of vignetting in an optical system arranged downstream of the light-source device  100  can be substantially prevented, and thus the utilization efficiency of light can be improved. 
     The embodiments of the present disclosure are described below. The embodiments described below indicate some examples of the light source optical system, the light-source device, and the image projection apparatus, and the configurations thereof may be changed where appropriate. Further, the respective embodiments may be combined where appropriate. 
       FIG. 10  is a schematic diagram of a projector  1  (image projection apparatus) provided with a light-source device  20  according to a first embodiment. As illustrated in  FIG. 10 , the projector  1  includes a housing  10 , a light-source device  20 , an illumination optical system  30 , an image forming element (image display element)  40 , a projection optical system  50 , and a cooling device  60 . 
     The housing  10  houses the light-source device  20 , the illumination optical system  30 , the image forming element  40 , the projection optical system  50 , and the cooling device  60 . The light-source device  20  emits, for example, light beams having wavelengths corresponding to colors of RGB. An inner configuration of the light-source device  20  is described later in detail. 
     The illumination optical system  30  illuminates the image forming element  40  substantially uniformly with the light uniformized by a light tunnel  29 , which is described later, included in the light-source device  20 . The illumination optical system  30  includes, for example, one or more lenses and one or more reflecting surfaces. 
     The image forming element  40  modulates light provided for illumination by the illumination optical system  30  (light from a light-source optical system of the light-source device  20 ) to form an image. The image forming element  40  includes, for example, a digital micromirror device (DMD) or a liquid crystal display element. The image forming element  40  drives the minute mirror surface in synchronization with light beams (blue light, green light, red light, and yellow light) emitted from the illumination optical system  30 , and generates a color image. 
     The projection optical system  50  magnifies and projects the image (the color image) formed by the image forming element  40  onto a screen (projection surface). The projection optical system  50  includes, for example, at least one lens. The cooling device  60  cools each of the elements and devices that take heat in the projector  1 . 
       FIGS. 11A and 11B  are illustrations of the configuration of the light-source device  20  according to the first embodiment.  FIG. 11A  indicates the optical path of the blue laser beam in the light-source device  20 , and  FIG. 11B  indicates the optical path of the fluorescence in the light-source device  20 . 
     As illustrated in  FIG. 11A , the light-source device  20  includes a laser source (excitation light source)  21 , a coupling lens  22 , a first optical system  23 , and a dichroic mirror  24  that is an example of an optical element, a second optical system  25 , a phosphor unit  26  as an example of the wavelength conversion unit, a refractive optical system  27 , a color wheel  28 , and a light tunnel  29  as an example of the light mixing element, which are sequentially arranged in the light propagation direction. 
     The color wheel  28  is described with reference to  FIG. 10 . In the present embodiment, the color wheel  28  is described as a component of the light-source device  20 . However, the configuration of the light-source device  20  is not limited thereto, and the color wheel  28  may not be included in the light-source device  20 . 
     In the laser source  21 , for example, a plurality of light sources are arranged in array to emit a plurality of laser beams. The laser source  21  emits, for example, light (blue laser beam) in a blue band where the center wavelength of emission intensity is 455 nm. Hereinafter, the blue laser beam is referred to simply as blue light. The blue light emitted from the laser source  21  is linearly polarized light whose polarization direction is a specific direction, and is also used as excitation light that is excited by fluorescent material or phosphor of the phosphor unit  26 , which is to be described later. 
     The light emitted by the laser source  21  is not limited to light in the blue wavelength band and may be light with wavelengths that can excite the fluorescent material. Further, the laser source  21  has a plurality of light sources in the first embodiment, but is not limited thereto. In some examples, the laser source  21  may be configured by one light source. In addition, the laser source  21  may be configured as a plurality of light sources arranged in array on a substrate, but is not limited thereto, and may have another arrangement configuration. 
     The coupling lens  22  is a lens that receives blue light emitted from the laser source  21  and converts the blue light into parallel light (collimated light). In the following description, the term “parallel light” is not limited to light that is completely collimated (parallelized), but includes substantially collimated light. The number of coupling lenses  22  may be increased or decreased in accordance with an increase or a decrease in the number of light sources of the laser source  21  so as to correspond to the number of light sources of the laser source  21 . 
     In the light-source device  20  according to the present embodiment, the laser source  21  and the coupling lens  22  constitute a light source unit. For example, the laser source  21  is configured by a plurality of laser diodes arranged in rows and columns. In other words, the light source unit includes the laser diodes and the coupling lenses  22  arranged on the light-emission surface side of the laser diodes. 
       FIG. 12  is an illustration of a main part of the light source unit included in the light-source device  20  according to the first embodiment. In the light source unit illustrated in  FIG. 12 , each coupling lens  22  is arranged to face a laser diode  21 A. In the light source unit, when θ denotes a divergence angle of the blue light (excitation light) emitted from each laser diode  21 A, the divergence angle being larger one between the row direction and the column direction, P denotes a pitch between adjacent laser diodes  21 A, and L denotes a distance from a light-emitting point of a laser diode  21 A to a corresponding coupling lens  22 , the interval (P/L tan θ) between the laser diodes  21 A is configured to satisfy Formula (1) below: 
       1≤ P/L  tan θ≤4  (1)
 
     Most preferably, the interval between the laser diodes  21 A is configured to satisfy Formula (2) below: 
         P/L  tan θ=2  (2)
 
     Satisfying Formula (2) enables the downsizing of the light-diode  21 A to be incident on only the corresponding one of the coupling lenses  22 . Accordingly, the light emitted from each laser diode  21 A is prevented from being erroneously incident on another coupling lens adjacent to the corresponding coupling lens. Thus, a decrease in the utilization efficiency of light can be substantially prevented. 
     Note that the plurality of laser diodes  21 A included in the light source unit are preferably arranged on the same substrate. With such an arrangement of the plurality of laser diodes  21 A on the same substrate, the area of light emitted from the light source unit can be reduced, so that vignetting of light in various optical elements on the optical path can be substantially prevented. Thus, the utilization efficiency of light can be improved. 
     The first optical system  23  has positive power as a whole, and includes a large-diameter lens  23   a  and a negative lens  23   b  in order from the laser source  21  side to the phosphor unit  26  side. The large-diameter lens  23   a  is an example of a large-diameter element, and has positive power. The large-diameter lens  23   a  is a lens that converges and combines the collimated light beams emitted from the coupling lenses  22 . The negative lens  23   b  is an example of a collimating element, and is configured by a lens that converts the blue light converged by the large-diameter lens  23   a  into parallel light (collimated light). The first optical system  23  guides the blue light (excitation light) that has been substantially collimated by the coupling lens  22  and has been incident on the first optical system  23  to the dichroic mirror  24  while converging the blue light. 
     The dichroic mirror  24  is arranged obliquely with respect to the propagation direction of the blue light emitted from the first optical system  23 . More specifically, the dichroic mirror  24  is disposed with the front end portion tilted downward with respect to the propagation direction of the blue light emitted from the first optical system  23 . The dichroic mirror  24  has an optical property that is capable of reflecting the blue light substantially collimated by the first optical system and also capable of transmitting the fluorescence (the second colored light) converted by the phosphor unit  26 . For example, the dichroic mirror  24  is provided with a coat having the above-described optical property. 
       FIG. 13  is an illustration of an example of the dichroic mirror  24  of the light-source device  20  according to the first embodiment.  FIG. 13  indicates the dichroic minor  24  as viewed from the incident direction of the blue light emitted from the first optical system  23  side. As illustrated in  FIG. 13 , the dichroic mirror  24  is divided into two regions  24 A and  24 B. Hereinafter, the regions  24 A and  24 B are referred to as a first region  24 A and a second region  24 B, respectively. 
     The first region  24 A has the optical property that reflects the blue light emitted from the first optical system  23  (the negative lens  23   b ) while transmitting the fluorescence converted from the blue light by the phosphor of the phosphor unit  26  to be described later. The first region  24 A forms the reflecting surface  102   a  as illustrated in  FIG. 1A . The second region  24 B has an optical property capable of transmitting the blue light and the fluorescence. 
     The first region  24 A is disposed on the optical axis of the first optical system  23 , but is not disposed on the optical axis of the second optical system  25 . The first region  24 A is disposed closer to the first optical system  23  (the negative lens  23   b ) side relative to the optical axis of the second optical system  25 . The second region  24 B is not disposed on the optical axis of the second optical system  25 , and disposed closer to the opposite side of the first optical system  23  relative to the optical axis of the second optical system  25 . 
     The second optical system  25  has positive power as a whole, and includes a positive lens  25 A and a positive lens  25 B in order from the laser source  21  side to the phosphor unit  26  side. The second optical system  25  serves to converge the blue light reflected by the dichroic mirror  24  while guiding the blue light to the phosphor unit  26 . Further, the second optical system  25  collimates the fluorescence light (the fluorescence) emitted from the phosphor unit  26 . Note that the second optical system  25  is an example of the focusing element. 
     The blue light guided by the second optical system is incident on the phosphor unit  26 . The phosphor unit  26  switches between the function of reflecting the blue light emitted from the second optical system  25  and the function of causing the blue light to work as the excitation light while converting the blue light into fluorescence having a different wavelength band from a wavelength band of the blue light by using the phosphor. The fluorescence converted by the phosphor unit  26  is, for example, light in a yellow wavelength band where the center wavelength of the emission intensity is 550 nm. 
       FIGS. 14A and 14B  are illustrations of the configuration of the phosphor unit  26  of the light-source device  20  according to the first embodiment. In  FIG. 14A , the phosphor unit  26  is viewed from the incident direction of the blue light. In  FIG. 14B , the phosphor unit  26  is viewed from the direction orthogonal to the incident direction of the blue light. The configuration of the phosphor unit  26  illustrated in  FIGS. 14A and 14B  is only one example, is not limited thereto, and may be changed where appropriate. 
     As illustrated in  FIG. 14A , the phosphor unit  26  includes a disk member (substrate or a disk body)  26 A and a drive motor  26 C (a drive unit) driven to rotate around a rotation axis  26 B that is the straight line perpendicular to a plane of the disk member  26 A. The disk member  26 A may be, but is not limited to, for example, a transparent substrate or a metal substrate (for example, an aluminum substrate). 
     A large portion in the circumferential direction (in the first embodiment, an angular range of larger than 270°) of the phosphor unit  26  (disk member  26 A) is assigned to a fluorescent region  26 D, and a small portion in the circumferential direction (in the first embodiment, an angular range of smaller than 90°) is assigned to an excitation-light reflective region  26 E. The excitation-light reflective region  26 E constitutes an example of a first area that reflects (or diffusely reflects) the excitation light reflected by the dichroic mirror  24 . The fluorescent region  26 D constitutes an example of an area that converts the excitation light reflected by the dichroic mirror  24  into fluorescence (fluorescence light) and emits the fluorescence light. The fluorescent region  26 D includes a reflection coat  26 D 1 , a phosphor layer  26 D 2 , and an anti-reflection coat (AR coat)  26 D 3  layered in this order from a lower-layer side toward an upper-layer side. 
     The reflection coat  26 D 1  has a characteristic of reflecting light in a wavelength region of the fluorescence (emission) by the phosphor layer  26 D 2 . When the disk member  26 A is made of a metal substrate with high reflectivity, the reflection coat  26 D 1  may be omitted. In other words, the disk member  26 A may have the function of the reflection coat  26 D 1 . 
     The phosphor layer  26 D 2  may use, for example, a substance in which a fluorescent material is dispersed into an organic or inorganic binder, a substance in which a crystal of a fluorescent material is directly formed, or a rare-earth phosphor such as a Ce:YAG-based substance. The phosphor layer  26 D 2  forms an example of a wavelength conversion member that converts at least a portion of the excitation light into fluorescence light having a wavelength different from that of the excitation light and emits the fluorescence light. The wavelength band of the fluorescence (emission or emitted light) by the phosphor layer  26 D 2  may be, for example, the wavelength band of yellow, blue, green, or red. In the first embodiment, an example is described in which fluorescence (emission) has the wavelength band of yellow. While the fluorescence material is used as the wavelength conversion element in this embodiment, a phosphorescent body or a non-linear optical crystal may be used. 
     The anti-reflection coat  26 D 3  has a characteristic of preventing reflection of light at a surface of the phosphor layer  26 D 2 . 
     A reflection coat (reflecting surface)  26 E 1  having a characteristic of reflecting light in the wavelength region of the blue light guided from the second optical system  25  is layered on the excitation-light reflective region  26 E. When the disk member  26 A is made of a metal substrate with high reflectivity, the reflection coat  26 E 1  may be omitted. In other words, the disk member  26 A may have the function of the reflection coat  26 E 1 . 
     By driving the disk member  26 A to rotate by the drive motor  26 C, the irradiation position of the blue light on the phosphor unit  26  moves with time. Consequently, a portion of the blue light (first colored light) incident on the phosphor unit  26  is converted by the fluorescent region (wavelength conversion region)  26 D into fluorescence (second colored light) with a wavelength different from the wavelength of the blue light (first colored light) and the fluorescence is emitted. The other portion of the blue light incident on the phosphor unit  26  is reflected by the excitation-light reflective region  26 E without a change from the blue light. 
     The numbers and ranges of the fluorescent region  26 D and the excitation-light reflective region  26 E can be freely determined, and various changes can be made in design. For example, two fluorescent regions and two excitation-light reflective regions may be alternately arranged in the circumferential direction at intervals of 90°. 
     Returning to  FIGS. 11A and 11B , the description of the configuration of the light-source device  20  will be continued. The refractive optical system  27  is a lens that condenses (converges) light (blue light and fluorescence) emitted from the second optical system  25 . The light (blue light and fluorescence) emitted from the phosphor unit  26  passes through the dichroic mirror  24 , and is then condensed (refracted) by the refractive optical system  27 . Thus, the condensed light is incident on the color wheel  28  (see  FIG. 10 ). The color wheel  28  is a member that separates the blue light and fluorescence light (fluorescence) generated by the phosphor unit  26  into desired colors. 
       FIGS. 15A and 15B  are illustrations of the configuration of the color wheel  28  of the light-source device  20  according to the first embodiment. In  FIG. 15A , the color wheel  28  is viewed from the incident direction of the blue light and the fluorescence. In  FIG. 15B , the color wheel  28  is viewed from the direction orthogonal to the incident direction of the blue light and the fluorescence. As illustrated in  FIGS. 15A and 15B , the color wheel  28  includes a toroidal-shape member  28 A and a drive motor (drive unit)  28 C that drives the toroidal-shape member  28 A to rotate around a rotation axis  28 B. 
     The toroidal-shape member  28 A is divided into a plurality of regions along the circumferential direction. In the toroidal-shape member  28 A, the regions divided along the circumferential direction are a diffusion region  28 D and filter regions  28 R,  28 G, and  28 Y. The diffusion region  28 D is a region that transmits and diffuses the blue light emitted from the phosphor unit  26 . The filter region  28 R is a region that transmits light having the wavelength range of the red component of the fluorescence emitted from the phosphor unit  26 . Similarly, the filter regions  28 G and  28 Y are regions that transmit light having the wavelength range of the green component and light having the wavelength range of the yellow component of the fluorescence emitted from the phosphor unit  26 , respectively. 
     In the above description, it is assumed that the color wheel  28  has regions through which the red, green, and yellow components of the fluorescence (the fluorescence light) are transmitted. However, the configuration of the color wheel  28  is not limited thereto. For example, the color wheel  28  may have regions through which a red component and a green component of the fluorescence light are transmitted. 
     The area ratio between the regions is determined based on design specification of the projector  1 . However, for example, since the diffusion region  28 D in the color wheel  28  transmits the blue light emitted from the phosphor unit  26 , the area ratio of the excitation-light reflective region  26 E with respect to the entire area of the disk member  26 A of the phosphor unit  26  may be equal to the area ratio of the diffusion region  28 D with respect to the entire area of the color wheel  28 . 
     The drive of the drive motor  28 C rotates the toroidal-shape member  28 A in the circumferential direction. With the rotation of the toroidal-shape member  28 A in the circumferential direction, the blue light emitted from the phosphor unit  26  is incident on the diffusion region  28 D and the fluorescence emitted from the phosphor unit  26  is sequentially incident on the filter regions  28 R,  28 G, and  28 Y. The light (the blue light and the fluorescence) emitted from the phosphor unit  26  is transmitted through the color wheel  28 , so that the blue light, green light, red light, and yellow light are sequentially emitted from the color wheel  28 . The light transmitted through each region of the color wheel  28  is then incident on the light tunnel  29 . 
     The light tunnel  29  is an optical element in which four mirrors form inner surfaces of a quadrangular prism. The light tunnel  29  serves as a light uniformizing element to cause the light incident on the one end of the quadrangular prism to be reflected plural times by the inner mirrors so as to make the distribution of the light uniform. The light tunnel  29  is disposed to enable the light (blue light and fluorescence) condensed by the refractive optical system  27  to be incident on the light tunnel  29 . In the first embodiment, the light tunnel  29  is described as an example of the light mixing element. However, no limitation is intended thereby. Alternatively, the light tunnel  29  may be, for example, a rod integrator or a fly-eye lens. 
       FIGS. 16A and 16B  are illustrations of an incident aperture  29 A of the light tunnel  29  in the light-source device  20  according to the first embodiment, as viewed from the incident direction of light.  FIGS. 16A and 16B  each indicates a projection range of the blue light projected onto the incident aperture  29 A of the light tunnel  29 . The light tunnel  29  is arranged slightly tilted as illustrated in  FIGS. 16A and 16B . The tilt angle of the light tunnel  29  is determined depending on a desired performance of the light-source device  20 . 
     In the light source unit of the light-source device  20  according to the first embodiment, as described above, the laser sources  21  (laser diodes  21 A) are arranged in array. As illustrated in  FIGS. 16A and 16B , each projection range on the incident aperture  29 A of the light tunnel  29  has an elliptical shape, each projection range being a range in which the blue light or the like emitted from a laser diode  21 A is projected onto the incident aperture  29 A (see  FIGS. 16A and 16B ). For example, as illustrated in  FIG. 16B , the projection ranges of the blue light or the like on the incident aperture  29 A are arranged such that the major axis of the elliptical shape of each projection range is substantially parallel to the short side of the incident aperture  29 A. With such an arrangement of the projection ranges of the blue light or the like on the incident aperture  29 A, the occurrence of the vignetting of the blue light or the like in the light tunnel  29  can be prevented. For another example as illustrated in  FIG. 16B , the projection ranges of the blue light or the like on the incident aperture  29 A may be arranged such that the major axis of the elliptical shape of each projection range is substantially parallel to the long side of the incident aperture  29 A. In the present embodiment, the elliptical shape refers to a shape having a difference between the full width at half maximum (FWHM) of the intensity distribution in the vertical direction of the projection range and the full width at half maximum (FWHM) of the intensity distribution in the horizontal direction. In other words, the elliptical shape is a shape without an isotropic intensity distribution. 
     A description is given below of the optical path of the blue light (hereinafter, referred to also as a blue light path) in the light-source device  20  with the above-described configuration, with reference to  FIG. 11A . The blue light path is an optical path of some light rays of the excitation light emitted from the laser source  21 , the some light rays to be reflected by the excitation-light reflective region  26 E of the phosphor unit  26 . 
     The blue light emitted from the laser source  21  is collimated by the coupling lens  22  to become a collimated light (parallel light). The blue light emitted from the coupling lens  22  is converged and combined by the large-diameter lens  23   a  of the first optical system  23 , and then converted into parallel light (collimated light) by the negative lens  23   b . The blue light emitted from the negative lens  23   b  is reflected by the first region  24 A of the dichroic mirror  24  and travels to the second optical system  25 . The first region  24 A constitutes a reflecting surface  102   a  that reflects the blue light emitted from the laser source  21  (see  FIG. 1 ). The point P at the center of the projection image of the excitation light described above is formed in the first region  24 A. 
     As described above, the first region  24 A of the dichroic mirror  24  is disposed closer to the first optical system  23  relative to the optical axis of the second optical system  25 . With this arrangement, the blue light path is caused to be incident on a portion of the second optical system  25  (more specifically, the positive lens  25 A), the portion being on the first optical system  23  side. Then, the blue light advances so as to approach the optical axis of the second optical system  25  while forming an angle with respect to the optical axis of the second optical system  25 , and is emitted from the second optical system  25  (more specifically, from the positive lens  25 B). The blue light emitted from the second optical system  25  is incident on the phosphor unit  26 . 
     In the present disclosure, it is assumed that the blue light incident on the phosphor unit  26  has been incident on the excitation-light reflective region  26 E. The blue light incident on the excitation-light reflective region  26 E is subjected to specular reflection. The blue light specularly reflected by the excitation-light reflective region  26 E is then incident on a portion of the second optical system  25  (more specifically, the positive lens  25 B), the portion being on the opposite side of the first optical system  23  side with respect to the optical axis of the second optical system  25 . Then, the blue light travels away from the optical axis of the second optical system  25  while forming an angle with respect to the optical axis of the second optical system  25 , and is emitted from the second optical system  25  (more specifically, the positive lens  25 A). 
     Blue light emitted from the second optical system  25  (more specifically, the positive lens  25 A) passes through the second region  24 B of the dichroic mirror  24 . The light flux of the blue light specularly reflected by the phosphor unit  26  or the light flux of the blue light emitted from the second optical system  25  and transmitted through the second region  24 B of the dichroic mirror  24  constitutes the above-described light flux Q of the excitation light emitted from the phosphor unit  103 . As described above, the second region  24 B of the dichroic mirror  24  has an optical property that transmits the excitation light (and the fluorescence). With this configuration, a decrease in the utilization efficiency of light is substantially prevented even when the light flux (light flux Q) of the blue light intersects with the dichroic mirror  24 . 
     The blue light transmitted through the second region  24 B of the dichroic mirror  24  is incident on the refractive optical system  27 . Then, the blue light advances so as to approach the optical axis of the refractive optical system  27  while forming an angle with respect to the optical axis of the refractive optical system  27 , and is incident on the light tunnel  29  through the color wheel  28 . The blue light incident on the light tunnel  29  is reflected plural times thereinside and homogenized (made uniform), and is then incident upon the illumination optical system  30  outside the light-source device  20 . 
     Next, the optical path of the fluorescence (hereinafter, appropriately referred to as a fluorescence light path) in the light-source device  20  is described according to the present embodiment with reference to  FIG. 11B . In  FIG. 11B , a part of the optical path of the fluorescence is omitted for convenience of explanation. The fluorescence light path is an optical path of some other light rays of the excitation light emitted from the laser source  21 , the wavelength of the some other light rays to be converted by the fluorescent region  26 D of the phosphor unit  26 . 
     Until the blue light emitted from the laser source  21  is guided to the phosphor unit  26 , the fluorescence light path is identical with the blue light path described above. In this case, it is assumed that the blue light incident on the phosphor unit  26  is incident on the fluorescent region  26 D. The blue light incident on the fluorescent region  26 D serves as excitation light and acts on the phosphor. The phosphor causes the conversion of the wavelength so that the fluorescence including, for example, a yellow wavelength band is generated and the fluorescence is reflected by the reflection coat  26 D 1  and the phosphor layer  26 D 2  to exhibit Lambertian reflectance. 
     The fluorescence Lambertian-reflected by the fluorescent region  26 D is converted by the second optical system  25  into parallel light. The fluorescence emitted from the second optical system  25  passes through the dichroic mirror  24  and is incident on the refractive optical system  27 . Then, the fluorescence advances so as to approach the optical axis of the refractive optical system  27  while forming an angle with respect to the optical axis of the refractive optical system  27 , and is incident on the light tunnel  29  through the color wheel  28 . The fluorescence incident on the light tunnel  29  is reflected plural times thereinside and homogenized (made uniform), and is then incident upon the illumination optical system  30  outside the light-source device  20 . 
     As described above, in the light-source device  20  according to the first embodiment, the optical path of the blue light emitted from the laser source  21  differs between before and after the reflection by the phosphor unit  26 . More specifically, the blue light path is formed so as to prevent the center (point P in  FIG. 1A ) of the projection image of the blue light projected from the laser source  21  onto the first region  24 A of the dichroic mirror  24 , from intersecting with the light flux (light flux Q in  FIG. 1A ) of the blue light reflected from the phosphor unit  26 . With this configuration, the light flux of the blue light emitted from the phosphor unit  26  does not intersect with the center of the projection image of the blue light emitted from the laser source  21 . This prevents these blue light beams from passing through the same location on the dichroic mirror  24 , which further prevents damage on the dichroic mirror  24  due to an increase in the light condensing density. Thus, the reliability can be increased. 
     Further, in the present embodiment, particular optical elements such as a phase-contrast plate and a polarization splitter (polarization beam splitter) are not used to separate the optical path of the blue light emitted from the phosphor unit  26 , from the other optical path. This configuration reduces the number of components and the cost for producing the light-source device  20 , thus achieving a reduction in the size of the light-source device  20 . Further, since optical components such as a phase-contrast plate and a polarization splitter are not used to operate the polarization of light, a decrease in the utilization efficiency of light due to the reflectivity, transparency, and absorptance of the optical components can be substantially prevented. 
     Further, in the light-source device  20  according to the first embodiment, the blue light emitted from the laser source  21  is a linearly polarized laser beam whose polarization direction is a specific direction. In light source unit, a plurality of laser sources  21  is arranged so that all the linearly polarized laser beams are oriented in the same direction. With such an arrangement, the directions of the linearly polarized laser beams emitted from the light source unit are made uniform. The direction of each linearly polarized laser beam is determined by the direction in which the light source unit is arranged. As illustrated in  FIGS. 16A and 16B , if the light source unit is tilted according to the tilt of the light tunnel  29 , the direction of each linearly polarized laser beam varies. In such a situation where the direction of the linearly polarized laser beams varies, if the polarization of light is controlled by using, for example, a polarization splitter, the utilization efficiency of light might decrease when the light passes through the polarization splitter. Since the polarization of light is not controlled in the light-source device  20  according to the first embodiment, the decrease in the utilization efficiency of light due to the tilt of the laser source  21  can be prevented. 
     A light-source device  201  according to a second embodiment differs in the configuration of the dichroic mirror from the light-source device  20  according to the first embodiment. Hereinafter, the configuration of the light-source device  201  according to the second embodiment is described below, focusing on differences from the light-source device  20  according to the first embodiment.  FIGS. 17A and 17B  are schematic views of a light-source device  201  according to the second embodiment.  FIG. 17A  indicates the optical path of the blue light in the light-source device  201 , and  FIG. 17B  indicates the optical path of the fluorescence in the light-source device  201 . In  FIGS. 17A and 17B , the same reference numerals are given to the same components as those in  FIGS. 11A and 11B , and the description thereof will be omitted. In  FIG. 17B , a part of the optical path of the fluorescence is omitted for convenience of explanation. 
     As illustrated in  FIGS. 17A and 17B , the light-source device  201  differs from the light-source device  20  according to the first embodiment in that the light-source device  201  includes a dichroic mirror  241 . The dichroic mirror  241  is arranged to be tilted in the same manner as in the dichroic mirror  24 . However, the dichroic mirror  241  has a shorter length than the dichroic mirror  24 . Since the dichroic mirror  241  is configured to have a shorter length, the size of the light-source device  201  can be reduced. The dichroic mirror  241  has the same optical property for a part of the dichroic mirror  24  (the first region  24 A). 
       FIG. 18  is an illustration of an example of the dichroic mirror  241  in the light-source device  201  according to the second embodiment.  FIG. 18  indicates the dichroic mirror  241  as viewed from the incident direction of the blue light (excitation light) emitted from the first optical system  23  side. As illustrated in  FIG. 18 , the dichroic mirror  241  has only a region  241 A. 
     Same as the first region  24 A, the region  241 A has the optical property that reflects the blue light emitted from the first optical system  23  (the negative lens  23   b ) while transmitting the fluorescence converted from the blue light by the phosphor of the phosphor unit  26 . The region  241 A is located at the same position as the first region  24 A. In other words, the region  241 A is disposed on the optical axis of the first optical system  23 , but is not disposed on the optical axis of the second optical system  25 . The region  241 A is disposed closer to the first optical system  23  side relative to the optical axis of the second optical system  25 . 
     A description is given below of the blue light path and the fluorescence light path in the light-source device  201  with the above-described configuration, with reference to  FIG. 17A  and  FIG. 17B . As illustrated in  FIG. 17A , the blue light emitted from the laser source  21  is reflected by the excitation-light reflective region  26 E of the phosphor unit  26  and emitted to the second optical system  25 , which is the same as in the blue light path according to the first embodiment. In the light-source device  201  according to the second embodiment, unlike the first embodiment, the blue light emitted from the second optical system  25  does not pass through the dichroic mirror  241 . The light flux (light flux Q) of the blue light emitted from the phosphor unit  26  does not intersect with the dichroic mirror  241 . The fluorescence light path is the same as in the first embodiment, as illustrated in  FIG. 17B . 
     In the light-source device  201  according to the second embodiment, the optical path of the blue light emitted from the laser source  21  differs between before and after the reflection by the phosphor unit  26 . Accordingly, same as the light-source device  20  according to the first embodiment, the configuration according to the second embodiment exhibits good reliability and achieves a reduction in size and cost. 
     Particularly, in the light-source device  201 , the width of the dichroic mirror  241  can be smaller than the width of the second optical system  25 . Accordingly, the size of the light-source device  201  can be reduced. Further, in the light-source device  201 , the optical path of the blue light reflected by the phosphor unit  26  does not pass through the dichroic mirror  241 . Accordingly, a decrease in the utilization efficiency of light due to the transparency of the dichroic mirror  241  can be substantially prevented. 
     A light-source device  202  according to a third embodiment differs from the light-source device  201  according to the second embodiment in the following points: 1) the light-source device  202  further includes another light source unit (hereinafter, referred to as a second light source unit) including a laser source  211  and coupling lenses  221 , in addition to the light source unit (hereinafter, referred to as a first light source unit where appropriate) including the laser source  21  and the coupling lenses  22 ; and 2) the light-source device  202  further includes a polarization optical component that combines excitation light emitted from the second light source unit with the excitation light emitted from the first light source unit. 
     Hereinafter, the configuration of the light-source device  202  according to the third embodiment is described below, focusing on differences from the light-source device  201  according to the second embodiment.  FIGS. 19A and 19B  are schematic diagrams of the light-source device  202  according to the third embodiment.  FIG. 19A  indicates the optical path of the blue laser beam in the light-source device  202  according to the third embodiment, and  FIG. 19B  indicates the optical path of the fluorescence in the light-source device  202  according to the third embodiment. In  FIGS. 19A and 19B , the same reference numerals are given to the same components as those in  FIGS. 17A and 17B , and the description thereof will be omitted. In  FIG. 19B , a part of the optical path of the fluorescence is omitted for convenience of explanation. 
     As illustrated in  FIGS. 19A and 19B , the light-source device  202  includes a laser source  211  and coupling lenses  221 , which constitute the second light source unit. The second light source unit is arranged so that the laser beams emitted from the laser source  211  are orthogonal to the laser beams emitted from the laser source  21  of the first light source unit. 
     The laser source  211  has the same configuration as the laser source  21 . In other words, in the laser source  211 , light sources (laser diodes) that emit a plurality of laser beams are arranged in array. The laser source  211  emits, for example, blue light in a blue band where the center wavelength of emission intensity is 455 nm. In this case, each of the laser sources  21  and  211  is configured to emit P-polarized light. In a similar manner to the coupling lens  22 , the coupling lens  221  is a lens that receives blue light emitted from the laser source  211  and converts the blue light into parallel light (collimated light). 
     The light-source device  202  includes a half-wave retarder  222  and a polarization splitter  223  that constitute a polarization optical component. The half-wave retarder  222  is arranged to face the plurality of coupling lenses  221 . The half-wave retarder  222  converts a P-polarized component of blue light emitted from the laser source  211  into an S-polarized component. The polarization splitter  223  is disposed in the optical path of the blue light emitted from the laser source  21  and the blue light emitted from the laser source  211 . The polarization splitter  223  has an optical property that reflects the S-polarized component of the blue light while transmitting the P-polarized component of the blue light. 
     The P-polarized component of the blue light emitted from the laser source  21  passes through the polarization splitter  223  and is incident on the large-diameter lens  23   a  of the first optical system  23 . After the P-polarized component of the blue light emitted from the laser source  211  is converted into the S-polarized light by the half-wave retarder  222 , the S-polarized light is reflected by the polarization splitter  223  and is incident on the large-diameter lens  23   a  of the first optical system  23 . Thus, the excitation light (blue light) from the second light source unit is combined with the excitation light (blue light) from the first light source unit. 
     The blue light path and the fluorescence light path in the light-source device  202  having such a configuration is described with reference to  FIGS. 19A and 19B . As illustrated in  FIGS. 19A and 19B , the blue light path and the fluorescence light path after being combined by the polarization splitter  223  and incident on the large-diameter lens  23   a  of the first optical system  23  are the same as those in the second embodiment. 
     In the light-source device  202  according to the third embodiment, the optical path of the blue light emitted from the laser source  21  differs between before and after the reflection of the phosphor unit  26 . Accordingly, in the same manner as in the light-source device  201  according to the second embodiment, the configuration according to the third embodiment exhibits good reliability and achieves a reduction in size and cost. Particularly, in the light-source device  202 , since the excitation light from the second light source unit is combined with the excitation light from the first light source unit, the luminance of the excitation light can be increased, and the utilization efficiency of light can be improved. Further, since the polarization is controlled by the half-wave retarder  222  and the polarization splitter  223  constituting the polarization optical component, the optical paths can be separated from and combined with each other regardless of the presence or absence of the polarization component of the light emitted from the light source. 
     A light-source device  203  according to a fourth embodiment differs from the light-source device  201  according to the second embodiment in that the light-source device  203  includes a phosphor unit  261  instead of the phosphor unit  26 . Hereinafter, the configuration of the light-source device  203  according to the fourth embodiment is described below, focusing on differences from the light-source device  201  according to the second embodiment. 
       FIGS. 20A and 20B  are schematic diagrams of a light-source device  203  according to the fourth embodiment.  FIG. 20A  indicates the optical path of the blue laser beam in the light-source device  203 , and  FIG. 20B  indicates the optical path of the fluorescence in the light-source device  203 . In  FIGS. 20A and 20B , the same reference numerals are given to the same components as those in  FIGS. 17A and 17B , and description thereof will be omitted. In  FIG. 20B , a part of the optical path of the fluorescence is omitted for convenience of explanation. 
     The light-source device  203  according to the fourth embodiment includes a phosphor unit  261  (hereinafter, referred to as a stationary phosphor unit where appropriate) that is not driven to rotate, instead of the phosphor unit  26  that is driven to rotate. The stationary phosphor unit  261  reflects a portion of the blue light (excitation light) emitted from the laser source  21  with a change from the blue light. The stationary phosphor unit  261  converts the other portions of the blue light into fluorescence and emit the fluorescence. 
       FIG. 21  is a schematic diagram of the stationary phosphor unit  261  in the light-source device  203  according to the fourth embodiment. In  FIG. 21 , the stationary phosphor unit  261  is viewed from a direction orthogonal to the incident direction of the blue light. As illustrated in  FIG. 21 , the stationary phosphor unit  261  is configured by stacking a phosphor  261   b  as the wavelength conversion member on a reflection member  261   a  that reflects excitation light. For example, the reflection member  261   a  and the phosphor  261   b  have a rectangular shape in plan view. The phosphor  261   b  is applied on the reflection member  261   a.    
     The phosphor  261   b  converts, for example, 80% of the incident blue light (excitation light) into fluorescence. Once the blue light is incident on the stationary phosphor unit  261 , 80% of the blue light acts as excitation light for the phosphor  261   b , and the phosphor  261   b  causes the conversion of the wavelength. As a result, the fluorescence including, for example, a yellow wavelength band where the center wavelength of emission intensity is 550 nm is generated, and the fluorescence is Lambertian-reflected by the phosphor  261   b  and the reflection member  261   a.    
     Of the incident blue light (excitation light), for example, 20% of the blue light does not act as the excitation light and is reflected by the reflection member  261   a . As a result, once the blue light is incident on the stationary phosphor unit  261 , the blue light and the fluorescence are emitted from the stationary phosphor unit  261  simultaneously. 
     The blue light path and the fluorescence light path in the light-source device  203  having such a configuration is described with reference to  FIGS. 20A and 20B . As illustrated in  FIGS. 20A and 20B , the blue light path and the fluorescence light path in the light-source device  203  are the same as those in the second embodiment except for the wavelength conversion and reflection in the stationary phosphor unit  261 . 
     In the light-source device  203  according to the fourth embodiment, the optical path of the blue light emitted from the laser source  21  differs between before and after the reflection of the phosphor unit  261 . Accordingly, in the same manner as in the light-source device  201  according to the second embodiment, the configuration according to the fourth embodiment exhibits good reliability and achieves a reduction in size and cost. Particularly, in the light-source device  203 , since the blue light and the fluorescence are emitted simultaneously by the stationary phosphor unit  261 , there is no need to drive the phosphor unit to rotate, and the manufacturing cost of the device can be reduced. In addition, since the motor for rotational driving is not used, noise can be reduced and a decrease in reliability due to the life of the motor is prevented. 
     A light-source device  204  according to a fifth embodiment differs from the light-source device  201  according to the second embodiment in including a mirror instead of the dichroic mirror  241  and also in the arrangement of the elements disposed downstream of the first optical system  23 . Hereinafter, the configuration of the light-source device  204  according to the fifth embodiment is described below, focusing on differences from the light-source device  201  according to the second embodiment. 
       FIGS. 22A and 22B  are schematic diagrams of the light-source device  204  according to the fifth embodiment.  FIG. 22A  indicates the optical path of the blue laser beam in the light-source device  204 , and  FIG. 22B  indicates the optical path of the fluorescence in the light-source device  204 . In  FIGS. 22A and 22B , the same reference numerals are given to the same components as those in  FIGS. 17A and 17B , and description thereof will be omitted. In  FIG. 22B , a part of the optical path of the fluorescence is omitted for convenience of explanation. 
     As illustrated in  FIG. 22A , the light-source device  204  includes a laser source (excitation light source)  21 , a coupling lens  22 , a first optical system  23 , a second optical system  25 , a phosphor unit  26 , a mirror  242 , a refractive optical system  27 , a color wheel  28 , and a light tunnel  29 , which are sequentially arranged in the light propagation direction. In  FIGS. 22A and 22B , the color wheel  28  is omitted for convenience of description. The color wheel  28  is described with reference to  FIG. 10 . 
     The mirror  242  is arranged to be tilted with respect to the propagation direction of the blue light emitted from the second optical system  25 . More specifically, the mirror  242  is disposed with the front end portion tilted upward with respect to the propagation direction of the blue light emitted from the second optical system  25 . The mirror  242  has an optical property that is capable of reflecting the blue light substantially collimated by the second optical system  25  while transmitting the fluorescence converted by the phosphor unit  26 . For example, the mirror  242  is provided with a coat having the above-described optical property. The mirror  242  is misaligned from the optical axis of the positive lens  25 A constituting the second optical system  25 . The mirror  242  has a reflecting surface  242 A on the surface facing the positive lens  25 A. 
     The blue light path in the light-source device  204  having such a configuration is described with reference to  FIG. 22A . The blue light path is an optical path of some light rays of the excitation light emitted from the laser source  21 , the some light rays to be reflected by the excitation-light reflective region  26 E of the phosphor unit  26 . 
     The blue light emitted from the laser source  21  is converted by the coupling lens  22  into parallel light. The blue light emitted from the coupling lens  22  is converged and combined by the large-diameter lens  23   a  of the first optical system  23 , and then converted into parallel light (collimated light) by the negative lens  23   b . The blue light emitted from the negative lens  23   b  is caused to be incident on a portion of the second optical system  25  (more specifically, the positive lens  25 A), the portion being on the refractive optical system  27  side (the upper side in  FIGS. 22A and 22B ). Then, the blue light advances so as to approach the optical axis of the second optical system  25  while forming an angle with respect to the optical axis of the second optical system  25 , and is emitted from the second optical system  25  (more specifically, from the positive lens  25 B). The blue light emitted from the second optical system  25  is incident on the phosphor unit  26 . 
     In the present disclosure, it is assumed that the blue light incident on the phosphor unit  26  has been incident on the excitation-light reflective region  26 E. The blue light incident on the excitation-light reflective region  26 E is subjected to specular reflection. The blue light specularly reflected by the excitation-light reflective region  26 E is then incident on a portion of the second optical system  25  (more specifically, the positive lens  25 B), the portion being on the opposite side (the lower side in  FIGS. 22A and 22B ) of the refractive optical system  27  side. Then, the blue light travels away from the optical axis of the second optical system  25  while forming an angle with respect to the optical axis of the second optical system  25 , and is emitted from the second optical system  25  (more specifically, the positive lens  25 A). 
     The blue light emitted from the second optical system  25  (more specifically, the positive lens  25 A) is reflected by the reflecting surface  242 A of the mirror  242  and is incident on the refractive optical system  27 . Then, the blue light advances so as to approach the optical axis of the refractive optical system  27  while forming an angle with respect to the optical axis of the refractive optical system  27 , and is incident on the light tunnel  29  through the color wheel  28 . The fluorescence incident on the light tunnel  29  is reflected plural times thereinside and homogenized (made uniform), and is then incident upon the illumination optical system  30  outside the light-source device  20 . 
     Next, the optical path of the fluorescence in the light-source device  204  is described according to the present embodiment with reference to  FIG. 22B . The fluorescence light path is an optical path of some other light rays of the excitation light emitted from the laser source  21 , the wavelength of the some other light rays to be converted by the fluorescent region  26 D of the phosphor unit  26 . 
     Until the blue light emitted from the laser source  21  is guided to the phosphor unit  26 , the fluorescence light path is identical with the blue light path described above. In this case, it is assumed that the blue light incident on the phosphor unit  26  is incident on the fluorescent region  26 D. The blue light incident on the fluorescent region  26 D serves as excitation light and acts on the phosphor. The phosphor causes the conversion of the wavelength so that the fluorescence including, for example, a yellow wavelength band is generated and the fluorescence is reflected by the reflection coat  26 D 1  and the phosphor layer  26 D 2  to thus exhibit Lambertian reflectance. 
     The fluorescence Lambertian-reflected by the fluorescent region  26 D is converted by the second optical system  25  into parallel light. The fluorescence emitted from the second optical system  25  is reflected by the reflecting surface  242 A of the mirror  242  and is incident on the refractive optical system  27 . Then, the fluorescence advances so as to approach the optical axis of the refractive optical system  27  while forming an angle with respect to the optical axis of the refractive optical system  27 , and is incident on the light tunnel  29  through the color wheel  28 . The fluorescence incident on the light tunnel  29  is reflected plural times thereinside and homogenized (made uniform), and is then incident upon the illumination optical system  30  outside the light-source device  20 . 
     In the light-source device  204  according to the fifth embodiment, the optical path of the blue light emitted from the laser source  21  differs between before and after the reflection of the phosphor unit  26 . Accordingly, in the same manner as in the light-source device  20  according to the first embodiment, the configuration according to the fifth embodiment exhibits good reliability and achieves a reduction in size and cost. 
     A light-source device  205  according to a sixth embodiment differs from the light-source device  204  according to the fifth embodiment in including a dichroic mirror in addition to the mirror  242 . Hereinafter, the configuration of the light-source device  205  according to the sixth embodiment is described below, focusing on differences from the light-source device  204  according to the fifth embodiment. 
       FIGS. 23A and 23B  are schematic diagrams of a light-source device  205  according to a sixth embodiment.  FIG. 23A  indicates the optical path of the blue laser beam in the light-source device  205 , and  FIG. 23B  indicates the optical path of the fluorescence in the light-source device  205 . In  FIGS. 23A and 23B , the same reference numerals are given to the same components as those in  FIGS. 22A and 22BA , and description thereof will be omitted. In  FIG. 23B , a part of the optical path of the fluorescence is omitted for convenience of explanation. 
     As illustrated in  FIG. 23A , the light-source device  205  has a dichroic mirror  243  near the mirror  242 . The dichroic mirror  243  has an optical property that is capable of reflecting the blue light substantially collimated by the first optical system while transmitting the fluorescence converted by the phosphor unit  26 . For example, the dichroic mirror  243  is provided with a coat having the above-described optical property. The dichroic mirror  243  is disposed on the reflecting surface  242 A side, in parallel with the mirror  242 . In other words, in the same manner as the mirror  242 , the dichroic mirror  243  is arranged obliquely with respect to the propagation direction of the blue light emitted from the second optical system  25 . Preferably, the dichroic mirror  243  is disposed on the optical axis of second optical system  25 . More preferably, the dichroic mirror  243  is disposed on the optical axis of the second optical system  25  and also on the optical axis of the refractive optical system  27 . 
     The blue light path in the light-source device  205  having such a configuration is described with reference to  FIG. 23A . The light-source device  205  according to the sixth embodiment differs from the light-source device  204  according to the fifth embodiment only in that the blue light beam emitted from the second optical system  25  is transmitted through the dichroic mirror  243  before being reflected by the reflecting surface  242 A of the mirror  242  in the blue light path in the light-source device  205 . For this reasons, description of the above-described functional units are omitted. 
     Next, the optical path of the fluorescence in the light-source device  205  is described according to the present embodiment with reference to  FIG. 23B . After the blue light emitted from the laser source  21  is converted into the fluorescent light and then converted into the parallel light by the second optical system  25 , the fluorescent light path is the same as the light-source device  204  according to the fifth embodiment. is there. In the light-source device  205 , the fluorescence emitted from the second optical system  25  is reflected not by the mirror  242  but by the dichroic mirror  243 , and is incident on the refractive optical system  27 . Then, the fluorescence advances so as to approach the optical axis of the refractive optical system  27  while forming an angle with respect to the optical axis of the refractive optical system  27 , and is incident on the light tunnel  29  through the color wheel  28 . The fluorescence incident on the light tunnel  29  is reflected plural times thereinside and homogenized (made uniform), and is then incident upon the illumination optical system  30  outside the light-source device  20 . 
     In the light-source device  205  according to the sixth embodiment, the optical path of the blue light emitted from the laser source  21  differs between before and after the reflection of the phosphor unit  26 . Accordingly, in the same manner as in the light-source device  20  according to the first embodiment, the configuration according to the fifth embodiment exhibits good reliability and achieves a reduction in size and cost. Particular, in the light-source device  205 , the dichroic mirror  243  is disposed on the optical axis of the second optical system  25  and also on the optical axis of the refractive optical system  27 . This can improve the utilization efficiency of the fluorescence light. 
     A light-source device  206  according to a seventh embodiment differs from the light-source device  205  according to the sixth embodiment in the following points: 1) the light-source device  206  further includes another light source unit (the second light source unit) including a laser source  211  and coupling lenses  221 , in addition to the light source unit (the first light source unit) including the laser source  21  and the coupling lenses  22 ; and 2) the light-source device  206  further includes a polarization optical component that combines excitation light emitted from the second light source unit with the excitation light emitted from the first light source unit. Hereinafter, the configuration of the light-source device  206  according to the seventh embodiment is described below, focusing on differences from the light-source device  205  according to the sixth embodiment. 
       FIGS. 24A and 24B  are schematic diagrams of the light-source device  206  according to the seventh embodiment.  FIG. 24A  indicates the optical path of the blue laser beam in the light-source device  206 , and  FIG. 24B  indicates the optical path of the fluorescence in the light-source device  206 . In  FIGS. 24A and 24B , the same reference numerals are given to the same components as those in  FIGS. 19A and 19B  and  FIGS. 23A and 23B , and description thereof will be omitted. In  FIG. 24B , a part of the optical path of the fluorescence is omitted for convenience of explanation. 
     As illustrated in  FIG. 24A , the light-source device  206  differs from the light-source device  205  according to the sixth embodiment in that the light-source device  206  includes a laser source  211  and a coupling lenses  221  constituting a second light source unit, and in that the light-source device  206  includes a half-wave retarder  222  and a polarization splitter  223  constituting the polarization optical component. For the configurations of the second light source unit, the half-wave retarder  222 , and the polarization splitter  223 , refer to the description of the light-source device  202  according to the third embodiment in in  FIGS. 19A and 19B . 
     The blue light path in the light-source device  206  having such a configuration is described with reference to  FIG. 24A . As illustrated in  FIG. 24A , the blue light path from the laser source  21  and the laser source  211  to the first optical system  23  is the same as that of the light-source device  202  according to the third embodiment (see  FIG. 19A ). The blue light path from the first optical system  23  to the light tunnel  29  is the same as that of the light-source device  205  according to the sixth embodiment (see  FIG. 23A ). For this reasons, the description of the above-described functional units are omitted. 
     Next, the optical path of the fluorescence in the light-source device  206  is described according to the present embodiment with reference to  FIG. 24B . In the light-source device  206 , the fluorescence light path from the laser source  21  and the laser source  211  to the first optical system  23  is the same as in the light-source device  202  according to the third embodiment. The fluorescence light path from the first optical system  23  to the light tunnel  29  is the same as in the light-source device  205  according to the sixth embodiment (see  FIG. 23A ). Therefore, a detailed description thereof will be omitted. 
     In the light-source device  206  according to the seventh embodiment, the optical path of the blue light emitted from the laser source  21  differs between before and after the reflection of the phosphor unit  26 . Accordingly, in the same manner as in the light-source device  20  according to the first embodiment, the configuration according to the first embodiment exhibits good reliability and achieves a reduction in size and cost. Particularly, in the light-source device  206 , since the excitation light from the second light source unit is combined with the excitation light from the first light source unit, the luminance of the excitation light can be increased, and the utilization efficiency of light can be improved. Further, since the polarization is controlled by the half-wave retarder  222  and the polarization splitter  223  constituting the polarization optical component, the optical paths can be separated from and combined with each other regardless of the presence or absence of the polarization component of the light emitted from the light source. 
     A light-source device  207  according to an eight embodiment differs from the light-source device  204  according to the fifth embodiment in that the light-source device  207  includes a phosphor unit (stationary phosphor unit) that is not driven to rotate, instead of the phosphor unit  26  that is driven to rotates. Hereinafter, the configuration of the light-source device  207  according to the eighth embodiment is described below, focusing on differences from the light-source device  204  according to the fifth embodiment. 
       FIGS. 25A and 25B  are schematic diagrams of a light-source device  207  according to the eighth embodiment.  FIG. 25A  illustrates the optical path of the blue laser beam in the light-source device  207 , and  FIG. 25B  illustrates the optical path of the fluorescence light in the light-source device  207 . In  FIGS. 25A and 25 , the same reference numerals are given to the same components as those in  FIGS. 20A and 20B  and  FIGS. 23A and 23B , and description thereof will be omitted. In  FIG. 24B , a part of the optical path of the fluorescence is omitted for convenience of explanation. 
     As illustrated in  FIG. 25A , the light-source device  207  according to the eighth embodiment differs from the light-source device  204  according to the fifth embodiment in that the light-source device  207  includes a phosphor unit (stationary phosphor unit)  261  that is not driven to rotate, instead of the phosphor unit  26  that is driven to rotate. For the configurations of the stationary phosphor unit  261 , refer to the description of the light-source device  203  according to the fourth embodiment in in  FIGS. 20A and 20B . 
     The blue light path in the light-source device  207  having such a configuration is described with reference to  FIG. 25A . As illustrated in  FIG. 25A , the blue light path from the laser source  21  to the stationary phosphor unit  261  is the same as that of the light-source device  205  according to the sixth embodiment. The blue light path from the stationary phosphor unit  261  to the light tunnel  29  is the same as that of the light-source device  205  according to the sixth embodiment. Therefore, a detailed description thereof will be omitted. 
     Next, the optical path of the fluorescence in the light-source device  207  is described according to the present embodiment with reference to  FIG. 24B . The blue light path from the laser source  21  to the stationary phosphor unit  261  in the light-source device  207  is the same as that of the light-source device  205  according to the sixth embodiment. The fluorescence light path from the stationary phosphor unit  261  to the light tunnel  29  is the same as that of the light-source device  205  according to the sixth embodiment. Therefore, a detailed description thereof will be omitted. 
     In the light-source device  207  according to the eighth embodiment, the optical path of the blue light emitted from the laser source  21  differs between before and after the reflection of the phosphor unit  261 . Accordingly, in the same manner as in the light-source device  20  according to the first embodiment, the configuration according to the eighth embodiment exhibits good reliability and achieves a reduction in size and cost. Particularly, in the light-source device  207 , since the blue light and the fluorescence are emitted simultaneously by the stationary phosphor unit  261 , there is no need to drive the phosphor unit to rotate, and the manufacturing cost of the device can be reduced. In addition, since the motor for rotational driving is not used, noise can be reduced and a decrease in reliability due to the life of the motor is prevented. 
     While specific examples desirable for the present disclosure are described in the above-described embodiments; however, the disclosure is not limited to the contents. In particular, the specific shapes and numerical values of the respective components exemplified in the embodiments are merely examples for implementing the disclosure. The technical scope of the disclosure should not be limitedly interpreted thereby. The present disclosure is not limited to the contents described in the embodiments, and may be properly modified within the scope of the disclosure. 
     The advantageous effects of the present invention are achieved by the following aspects: 
     In a first aspect, a light-source device ( 100 ) includes an excitation light source ( 101 ) configured to emit first colored light; an optical element ( 102 ) having a reflecting surface to reflect the first colored light emitted from the excitation light source ( 101 ); and a wavelength conversion unit ( 103 ) configured to emit the first colored light reflected by the optical element ( 102 ). The wavelength conversion unit ( 103 ) includes a wavelength conversion member ( 26 D 2 ) configured to convert at least a portion of the first colored light reflected by the optical element ( 102 ) and incident on the wavelength conversion unit ( 103 ), into second colored light having a wavelength different from a wavelength of the first colored light and emit the second colored light. A point P does not intersect with a light flux Q where the point P is a center of the first colored light on the reflecting surface of the optical element ( 102 ) and the light flux Q is a light flux of the first colored light emitted from the wavelength conversion unit ( 103 ). 
     As a second aspect, in the light-source device ( 100 ) according to the first aspect, the wavelength conversion unit ( 103 ) includes: a first area ( 26 E) to reflect or diffuse the first colored light reflected by the optical element ( 102 ) to emit the first colored light; and a second area ( 26 D) including the waveform conversion member ( 26 D 2 ), to convert the first colored light reflected by the optical element ( 102 ) and incident on the second area ( 26 D) into the second colored light and emit the second colored light. Upon the first colored light being incident on the wavelength conversion unit ( 103 ), the wavelength conversion unit ( 103 ) is configured to alternately emit the first colored light and the second colored light to an incident-plane side of the wavelength conversion unit ( 103 ) that the first colored light has been incident on. 
     As a third aspect, in the light-source device ( 100 ) according to the first aspect, the wavelength conversion unit ( 103 ) includes an area to receive the first colored light reflected by the optical element ( 102 ) and the area includes the wavelength conversion member ( 261   b ). The wavelength conversion member ( 261   b ) is configured to convert a portion of the first colored light incident on the area into the second colored light and reflect the other portion of the first colored light. Upon the first colored light being incident on the wavelength conversion unit ( 103 ), the wavelength conversion unit ( 103 ) is configured to emit the first colored light and the second colored light together to an incident-plane side of the wavelength conversion unit ( 103 ) that the first colored light has been incident on. 
     As a fourth aspect, in the light-source device ( 100 ) according to any one of the first aspect to the third aspect, further includes a light mixing device ( 104 ) configured to mix at least one of the first colored light and the second colored light emitted from the wavelength conversion unit ( 103 ); and a light guide configured to guide the at least one of the first colored light and the second colored light emitted from the wavelength conversion unit ( 103 ) to the light mixing device ( 104 ). 
     As a fifth aspect, in the light-source device ( 100 ) according to the fourth aspect, when a point R is a center of a projection image of the first colored light projected on the wavelength conversion unit ( 103 ), the light mixing device ( 104 ) is disposed on the normal to the point R on an exit plane ( 103   a ) of the wavelength conversion unit ( 103 ). 
     As a sixth aspect, the light-source device ( 100 ) according to any one of the first aspect to the fifth aspect, further includes a focusing element ( 105 ) disposed in an optical path between the optical element ( 102 ) and the wavelength conversion unit ( 103 ), the focusing element ( 105 ) configured to converge the first colored light reflected by the optical element ( 102 ) and substantially collimate the second colored light emitted from the wavelength conversion unit ( 103 ). A position of the point R is different from a position of a point S when the point S is a point of intersection of an incident plane of the wavelength conversion unit ( 103 ) that the first colored light converged by the focusing element ( 105 ) has been incident on and a straight line (L 1 ) connecting the point P and a center of a projection image on an incident plane of the focusing element ( 105 ) that the first colored light reflected by the reflecting surface has been incident on, the projection image being formed by the first colored light. 
     As a seventh aspect, in the light-source device ( 100 ) according to the sixth aspect, wherein the straight line (L 1 ) intersects perpendicularly with the incident plane of the wavelength conversion unit ( 103 ) that the first colored light has been incident on. 
     As an eighth aspect, the light-source device ( 100 ) according to the fourth aspect, further includes a refractive optical element ( 106 ) configured to guide at least one of the first colored light and the second colored light emitted from the wavelength conversion unit ( 103 ) to an incident aperture ( 104   a ) of the light mixing element ( 104 ), wherein the light mixing device ( 104 ) is a rod integrator. 
     As a ninth aspect, in the light-source device ( 100 ) according to the eighth aspect, a center of a projection image of the first colored light projected on the incident aperture ( 104   a ) of the rod integrator, a center of a projection image of the second colored light projected on the incident aperture ( 104   a ), and the optical axis of the refractive optical element ( 106 ) intersect at one point. 
     As a tenth aspect, in the light-source device ( 100 ) according to the eighth aspect to the ninth aspect, a plane including the straight line (L 1 ) and another straight line (L 2 ) is substantially parallel to a short side of the incident aperture ( 104   a ) of the rod integrator, said another straight line (L 2 ) being a straight line connecting a center of a projection image of the first colored light on the incident aperture ( 104   a ) of the rod integrator and a point R that is a center of a projection image of the first colored light on the wavelength conversion unit ( 103 ). As an eleventh aspect, in the light-source device ( 100 ) according to any one of the eighth aspect to the tenth aspect, the plane including the straight line (L 1 ) and another straight line (L 2 ) is substantially parallel to a short side of a light-emitting surface of the excitation light source ( 101 ), said another straight line (L 2 ) being a straight line connecting a center of a projection image of the first colored light on the incident aperture ( 104   a ) of the rod integrator and a point R that is a center of a projection image of the first colored light on the wavelength conversion unit ( 103 ). 
     As a twelfth aspect, in the light-source device ( 100 ) according to any one of the eighth aspect to the eleventh aspect, an angle β is smaller than 40° when the angle β is an angle between the incident aperture ( 104   a ) of the rod integrator and the incident plane of the first colored light with respect to the incident aperture ( 104   a ). 
     As a thirteenth aspect, in the light-source device ( 100 ) according to any one of the eighth aspect to the twelfth aspect, an angle θ 1  is smaller than an angle θ 2  when the angle θ 1  is a maximum incident angle of a light ray of the first colored light with respect to the incident aperture ( 104   a ) and the angle θ 2  is a maximum incident angle of a light ray of the second colored light with respect to the incident aperture ( 104   a ) of the rod integrator. 
     As a fourteenth aspect, in the light-source device ( 100 ) according to any one of the eighth aspect to the twelfth aspect, an angle θ 1  is equal to an angle θ 2  when the angle θ 1  is a maximum incident angle of a light ray of the first colored light with respect to the incident aperture ( 104   a ) and the angle θ 2  is a maximum incident angle of a light ray of the second colored light with respect to the incident aperture ( 104   a ) of the rod integrator. 
     As a fifteenth aspect, in the light-source device ( 100 ) according to any one of the eighth aspect to the fourteenth aspect, the rod integrator has an exit aperture ( 104   b ) larger than the incident aperture ( 104   a ). 
     As a sixteenth aspect, in the light-source device ( 100 ) according to any one of the eighth aspect to the fifteenth aspect, the rod integrator is a glass rod integrator, and wherein an angle θglass is larger than each of the angle θ 1  and the angle θ 2  when the angle θglass is a total reflection condition of the glass rod integrator. 
     As a seventeenth aspect, in the light-source device ( 100 ) according to any one of the eighteenth aspect to the sixteenth aspect, the excitation light source ( 101 ) includes a plurality of laser diodes arranged in array. A projection range of the first colored light emitted from each of the laser diodes on the incident aperture ( 104   a ) of the rod integrator has an elliptical shape whose major axis is substantially parallel to a long side or the short side of the incident aperture ( 104   a ) of the rod integrator. 
     As an eighteenth aspect, the light-source device ( 100 ) according to the seventeenth aspect, further includes a light source unit ( 21 ,  22 ) including the plurality of laser diodes. The plurality of laser diodes is disposed on the same substrate in the light source unit ( 21 ,  22 ). 
     As a nineteenth aspect, the light-source device ( 100 ) according to any one of the first aspect to the eighteenth aspect, further includes coupling lenses ( 22 ). The light source unit ( 21 ,  22 ) includes the excitation light source ( 101 ) and the coupling lenses ( 22 ). The excitation light source ( 101 ) includes the plurality of laser diodes arranged in rows and columns and each of the coupling lenses ( 22 ) is disposed on an exit-plane side of a corresponding one of the plurality of laser diodes. An interval between the laser diodes satisfies Formula below: 
       1≤ P/L  tan θ≤4
 
     where
 
θ denotes a divergence angle of the first colored light emitted from each of the plurality of laser diodes, the divergence angle being a larger angle between an angle in a row direction and an angle in a column direction,
 
P denotes a pitch between adjacent laser diodes, and
 
L denotes a distance from a light-emitting point of each of the plurality of laser diodes to a corresponding one of the coupling lenses.
 
     As a twentieth aspect, in the light-source device ( 100 ) according to any one of the first aspect to the nineteenth aspect, The optical element ( 102 ) has an optical property to transmit the first colored light and the second colored light, and the optical element ( 102 ) is disposed to intersect with the light flux Q. 
     As a twenty-first aspect, in the light-source device ( 100 ) according to any one of the first aspect to the nineteenth aspect, the optical element ( 102 ) has an optical property to transmit the first colored light and the second colored light, and the optical element ( 102 ) is disposed to not intersect with the light flux Q. 
     As a twenty-second aspect, in the light-source device ( 100 ) according to the twentieth aspect or twenty-first aspect, the reflecting surface of the optical element ( 102 ) has an optical property to reflect the first colored light and transmit the second colored light. As a twenty-third aspect, in the light-source device ( 100 ) according to any one of the second aspect, the fourth aspect to the twenty-second aspect, the wavelength conversion unit ( 103 ) includes: a disk body ( 26 A) whose circular substrate is divided into the first area ( 26 E) and the second area ( 26 D) in a circumferential direction; and a drive unit ( 26 C) configured to be driven to rotate around a rotation axis ( 26 B) that is a straight line passing through a center of the disk body ( 26 A) and perpendicular to a plane of the disk body ( 26 A). 
     As a twenty-fourth aspect, the light-source device ( 100 ) according to any one of the first aspect to the twenty-third aspect, further includes a large-diameter element ( 23   a ) having positive power and a collimating element ( 23   b ) having negative power, arranged in that order in a direction of travel of the first colored light between the excitation light source ( 101 ) and the optical element ( 102 ). The first colored light emitted from the excitation light source ( 101 ) is converged by the large-diameter element ( 23   a ), is substantially collimated by the collimating element ( 23   b ), and is incident on the optical element ( 102 ). 
     As a twenty-fifth aspect, an image projection apparatus ( 1 ) includes the light-source device ( 100 ) according to any one of the first aspect to the twenty-fourth aspect; an image display element ( 40 ) to generate an image of light emitted from the light-source device ( 100 ); an illumination optical system ( 30 ) configured to guide the light emitted from the light-source device ( 100 ) to the image display element; and a projection optical system ( 50 ) configured to project the image generated by the image display element ( 40 ). 
     As a twenty-sixth aspect, a light source optical system ( 102 ,  103 ) includes an optical element ( 102 ) having a reflecting surface to reflect first colored light emitted from an excitation light source; and a wavelength conversion unit ( 103 ) configured to emit the first colored light reflected by the optical element ( 102 ), the wavelength conversion unit ( 103 ) including a waveform conversion member ( 26 D 2 ) configured to convert at least a portion of the first colored light reflected by the optical element ( 102 ) and incident on the wavelength conversion unit ( 103 ), into second colored light having a wavelength different from a wavelength of the first colored light and emit the second colored light. A point P does not intersect with a light flux Q where the point P is a center of the first colored light on the reflecting surface of the optical element ( 102 ) and the light flux Q is a light flux of the first colored light emitted from the wavelength conversion unit ( 103 ). 
     Numerous additional modifications and variations are possible in light of the above teachings. It is therefore to be understood that, within the scope of the above teachings, the present disclosure may be practiced otherwise than as specifically described herein. With some embodiments having thus been described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the scope of the present disclosure and appended claims, and all such modifications are intended to be included within the scope of the present disclosure and appended claims.