Abstract:
A light source unit is provided for securing light quantity and reducing in size, which comprises a light source made up of a reflector comprising a lamp accommodating opening and a light exiting opening a lamp comprising, in turn, a bulb for emitting light and electrode introducing portions which guide electrodes into the bulb, wherein the bulb is disposed such that the position of a focal point of radiated light which is radiated from the bulb and reflected by the reflector when the lamp is inserted into the reflector is situated at neither of the electrode introducing portions, an anomalous lens which is disposed to collect light emitted from the light source to be situated on an optical axis of the light emitted from the light source, a reflecting mirror for reflecting light which has exited from the anomalous lens, and a lens for collecting light from the reflecting mirror.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a light source unit and a projector system including the light source unit, and more particularly to a light source unit which is made small in size without reducing the utilizing efficiency of light from a light source and a projector system including the light source unit.  
         [0002]     A projector system is designed such that light emitted from a light source unit is passed through a color wheel and is then caused to enter a mirror tunnel to produce light of a uniform intensity distribution, and the light is projected while changing the quantity thereof for each pixel by a micromirror device or a liquid crystal display device, so as to display an image on a screen.  
         [0003]     As a conventional light source unit, for example, there exists a light source unit  60  which includes, as shown in  FIG. 13 , a light source  61  which emits light, a convex lens  62  disposed on an optical axis K to collect the light emitted from the light source  61  and a mirror tunnel  63  which the light which has exited from the light source  61  is caused to enter (refer to Patent Document No. 1).  
         [0004]     The light source  61  is made up of a reflector  64  and a lamp  65  which is inserted into the reflector  64 . The lamp  65  is made up of a bulb  66  and electrode introducing portions  69 ,  69 , and the bulb  66  is designed to be inserted into the reflector  64 . Note that the color wheel is omitted from the illustration in  FIG. 13 .  
         [0005]     Here, since part of light emitted from the bulb  66  and reflected by an inner wall of the reflector  64  resides within the electrode introducing portions  69 , the quantity of effective light is dampened. In addition, the convex lens  62  cannot shine sufficiently the light reflected by the reflector  64  on to an entrance surface  63   a  of the mirror tunnel  63 .  
         [0006]     Due to this, the light source unit  61  needs to have a certain size or larger in order to secure a certain quantity of light, and a projector system which incorporates therein the light source unit tends to be made large in size, the carriage and setting of the projector system made so large is not necessarily easy.  
         [0007]     In addition, although a small light source unit is preferable with a view to making small the whole projector system, a lamp in the light source unit is needs to have the certain size or larger with a view to securing the quantity of light. 
        Patent Document No. 1: Japanese Unexamined Patent Publication No. 6-51401        
 
       SUMMARY OF THE INVENTION  
       [0009]     According to a preferred aspect of the invention, there is provided a light source unit including a light source made up of a reflector in which a lamp accommodating opening and a light exiting opening are formed and whose inner surface is mirror finished and a lamp including, in turn, a bulb for emitting light and electrode introducing portions which guide electrodes into the bulb, wherein the bulb is disposed such that the position of a focal point of radiated light which is radiated from the bulb and reflected by an inner wall of the reflector when the lamp is inserted into the reflector from the accommodating opening is situated at neither of the electrode introducing portions, an anomalous lens which is disposed not only to collect light emitted from the light source but also to be situated on an optical axis of the light emitted from the light source, a reflecting mirror for reflecting light which has exited from the anomalous lens, and a lens for collecting light from the reflecting mirror.  
         [0010]     Furthermore, according to another preferred aspect of the invention, there is provided a projector system including a light source unit including, in turn, a light source made up of a reflector in which a lamp accommodating opening and a light exiting opening are formed and whose inner surface is mirror finished and a lamp including, in turn, a bulb for emitting light and electrode introducing portions which guide electrodes into the bulb, wherein the bulb is disposed such that the position of a focal point of radiated light which is radiated from the bulb and reflected by an inner wall of the reflector when the lamp is inserted into the reflector from the accommodating opening is situated at neither of the electrode introducing portions, an anomalous lens which is disposed not only to collect light emitted from the light source but also to be situated on an optical axis of the light emitted from the light source, a reflecting mirror for reflecting light which has exited from the anomalous lens, and a lens for collecting light from the reflecting mirror, a color wheel for converting light which has exited from the lens into light of a predetermined color, a mirror tunnel for guiding light which has exited from the lens, a condenser lens for collecting light which has exited from the mirror tunnel, a micromirror device for receiving light which has exited from the condenser lens to project an image, and a projection lens for enlarging the image projected from the micromirror device.  
         [0011]     Furthermore, according to a further preferred aspect of the invention, there is provided a light source unit including a light source made up of a reflector in which a lamp accommodating opening and a light exiting opening are formed and whose inner surface is mirror finished and a lamp including, in turn, a bulb for emitting light and electrode introducing portions which guide electrodes into the bulb, wherein the bulb is disposed such that the position of a focal point of radiated light which is radiated from the bulb and reflected by an inner wall of the reflector when the lamp is inserted into the reflector from the accommodating opening is situated at neither of the electrode introducing portions, and an anomalous lens which is disposed not only to collect light emitted from the light source but also to be situated on an optical axis of the light emitted from the light source.  
         [0012]     Furthermore, according to a preferred aspect of the invention, there is provided a projector system including a light source unit including, in turn, a light source made up of a reflector in which a lamp accommodating opening and a light exiting opening are formed and whose inner surface is mirror finished and a lamp including, in turn, a bulb for emitting light and electrode introducing portions which guide electrodes into the bulb, wherein the bulb is disposed such that the position of a focal point of radiated light which is radiated from the bulb and reflected by an inner wall of the reflector when the lamp is inserted into the reflector from the accommodating opening is situated at neither of the electrode introducing portions, and an anomalous lens which is disposed not only to collect light emitted from the light source but also to be situated on an optical axis of the light emitted from the light source, a color wheel for converting light which has exited from the lens into light of a predetermined color, a mirror tunnel for guiding light which has exited from the lens, a condenser lens for collecting light which has exited from the mirror tunnel, a micromirror device for receiving light which has exited from the condenser lens to project an image, and a projection lens for enlarging the image projected from the micromirror device. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a plan view of an interior of a projector system according to a first embodiment of the invention.  
         [0014]      FIG. 2  is a schematic diagram showing the configuration of an optical system of the projector system according to the first embodiment.  
         [0015]      FIG. 3  is a schematic sectional view of a light source unit according to the first embodiment.  
         [0016]      FIGS. 4A, 4B ,  4 C are schematic diagrams showing a lamp used in the invention.  
         [0017]      FIG. 5  is a schematic perspective view of an anomalous lens used in the invention.  
         [0018]      FIG. 6  is a sectional view of the anomalous lens shown in  FIG. 5  taken along the line VI-VI.  
         [0019]      FIG. 7  is a schematic front view of a light source side lens surface of the anomalous lens shown in  FIG. 5 .  
         [0020]      FIG. 8A  is a front view of a side of a spherical lens on to which light is emitted, and  FIG. 8B  is a sectional view of the spherical lens taken along the line b-b in  FIG. 8A .  
         [0021]      FIG. 9  is a plan view of an interior of a projector system according to a second embodiment of the invention.  
         [0022]      FIG. 10  is a schematic diagram showing the configuration of an optical system of the projector system of the second embodiment.  
         [0023]      FIG. 11  is a schematic sectional view of a light source unit according to the second embodiment.  
         [0024]      FIG. 12  is a schematic sectional view representing a positional relationship between members making up the light source unit according to the second embodiment.  
         [0025]      FIG. 13  is a sectional view of a conventional light source unit. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
     First Embodiment  
       [0026]     Next, an embodiment of the invention will be described by reference to the accompanying drawings. However, the scope of the invention is not limited by an example illustrated in the drawings.  
         [0027]      FIG. 1  is a plan view showing an interior of a projector system according to an embodiment of the invention.  FIG. 2  is a schematic diagram showing the configuration of an optical system of the projector system according to the embodiment.  FIG. 3  is a schematic sectional view of a light source unit.  
         [0028]     As is shown in  FIG. 1 , a cooling fan  3  which sucks air from an upper surface thereof is disposed in the vicinity of a central portion of an interior of a case  2  of a projector system  1 . In addition, air suction ports  4 ,  4  are formed in a pair of sides of the case  2  which face each other. The air suction port in each side is formed by a plurality of holes. In addition, an air discharge port  5 , which is formed by a plurality of holes, is formed in one of sides of the case  2  where no air suction port  4  is formed. In addition, a power supply substrate  7  for controlling the whole of the projector system  1 , on which a power supply, not shown, is mounted, is disposed in the interior of the case  2 .  
         [0029]     In addition, a light source unit  6 , which is controlled by the power supply circuit board  7 , is disposed in the interior of the case  2  at a location lying in the vicinity of the side of the case  2  where the air discharge port  5  is provided. The light source unit  6  is made up of a light source  9 , an anomalous lens  10  (a rotary aspherical lens), a primary reflecting mirror  11  and a spherical lens  12 . As is shown in  FIG. 3 , the light source  9  is made up of a reflector  13  and a lamp  14  which is accommodated within the reflector  13 .  
         [0030]     The reflector  13  is formed into the shape of a multinominal surface. The multinominal surface shape of the reflector  13  is a shape which is expressed by an equation in which values shown in Table 1 are substituted for parameters in an equation (1) below.  
             (     Equation   ⁢             ⁢             ⁢   1     )                           z   =         cr   2       1   +       1   -       (     1   +   k     )     ⁢     c   2     ⁢     r   2               +     c   ⁢           ⁢   1   ⁢   r     +     c   ⁢           ⁢   2   ⁢     r   2       +     c   ⁢           ⁢   3   ⁢     r   3       +     c   ⁢           ⁢   4   ⁢     r   4                 (   1   )             
 
                   TABLE 1                           Diameter of Light exiting opening (mm)   33.955       Diameter of Lamp Accommodating Opening   11       (mm)       Conic Constant: k   −3.67011841E−01       Radius of curvature: c    7.62777804E−02       Coefficient: c1    5.03015585E−02       Coefficient: c2   −7.14558835E−03       Coefficient: c3    1.09782503E−03       Coefficient: c4   −2.91355712E−05                  
 
         [0031]     where, z denotes an axis in the direction of the optical axis (a direction in which light travels is regarded as positive), c denotes a radius of curvature, k denotes a Conic constant, and r(mm) is the length of a perpendicular when the perpendicular is drawn from an edge portion of a light exiting opening  15 , which will be described later on, to the optical axis K.  
         [0032]     In addition, the light exiting opening  15  from which light exits is provided in the reflector  13  as shown in  FIG. 3 . Furthermore, a lamp accommodating opening  16  is also provided in a proximal portion of the reflector  13 , so that the lamp  4  is designed to be accommodated from the lamp accommodating opening  16 .  
         [0033]     As is shown in  FIG. 4A , the lamp  14  is made up of a bulb  19  which emits light and electrode introducing portions  20 ,  20  which are provided at both ends of the bulb  19  in a direction of a major axis thereof so that electrodes are introduced into the bulb  19  therefrom. In addition, as is shown in  FIG. 3 , an arc  21  which produces a discharge of electricity is provided within the bulb  19 . The bulb  19  is disposed in the vicinity of the lamp accommodating opening  16  within the reflector  13  in such a manner that the position of a focal point (ST) of radiated light which is radiated from the bulb  19  and is reflected by an inner wall of the reflector  13  is formed further forward in a traveling direction of the radiated light than the electrode introducing portion  20 .  
         [0034]     As a specific shape of the bulb  19  used in this invention, a shape is raised which will be described below.  
         [0035]     Firstly, as is shown in  FIG. 4B , an ellipse A, which has a Conic constant of −0.91598, a radius of curvature of 4.175964, a major radius of 49.17239 mm and a minor radius of 14.32976 mm, is made to be situated in such a manner that a major axis L thereof intersects the optical axis K. As this occurs, the ellipse A is disposed such that the major axis L of the ellipse A intersects the optical axis K in a position which lies 5.25 mm from a point Q at one end toward a point R at the other end of the major axis L of the ellipse A (hereinafter, the point where the major axis L of the ellipse A interests the optical axis K is referred to as a point S).  
         [0036]     Next, an ellipse B is disposed such that a central point U thereof is situated in a position which lies 24.77409 mm from a central point T of the ellipse A toward the point Q and a minor axis N of the ellipse B becomes parallel to a minor axis M of the ellipse A. The ellipse B has a Conic constant of −0.85721, a radius of curvature of 3.110047 mm, a major radius of 21.7811 mm and a minor radius of 8.2304455 mm.  
         [0037]     Next, the ellipse A and the ellipse B are rotated about the optical axis K. Then, a solid spindle C shown in  FIG. 4C  is formed by an arc O of the ellipse A which rotates about the optical axis K and lies closer to the point Q than the optical axis K.  
         [0038]     An external edge portion of the solid spindle C corresponds to an outer circumferential portion of the bulb used in the embodiment. In addition, an internal space of a spindle D which is formed by virtue of the rotation of an arc P of the ellipse B which lies closer to the point Q than the optical axis K about the optical axis K corresponds to a space in the bulb where the arc  21  is accommodated.  
         [0039]     In addition, the shape of a space defined between the spindle C and the spindle D corresponds to the shape of a glass member which accommodates therein the arc  21 , and the point S corresponds to the position of the arc  21 . As is shown in  FIG. 4A , the electrode introducing portions  20 ,  20  for supplying power to the arc  21  are attached to the longitudinal ends of the bulb  19  which is formed as described above, whereby the lamp  14  used in the invention is formed.  
         [0040]     An anomalous lens  10  is disposed in a traveling direction of light that has exited from the light exiting opening  15  of the reflector  13 . There is imposed no limitation on the shape of the anomalous lens  10 , provided that the lens can collect sufficiently light that has exited from the light exiting opening  15  so as to cause the light so collected to exit in the light traveling direction. An example of a lens which can used as the anomalous lens  10  will be described below.  
         [0041]      FIG. 5  is a schematic perspective view of an example of an anomalous lens  10 , and  FIG. 6  is a sectional view taken along the line VI-VI of the anomalous lens  10  shown in  FIG. 5 .  
         [0042]     As is shown in  FIGS. 5 and 6 , a lens surface  22  of the anomalous lens  10  which lies on a side thereof where light that has exited from the light exiting opening  15  of the reflector  13  is shone is defined by a flat surface portion formed around a circumferential edge portion of the lens surface  22 , a swelling portion which is formed in such a manner as to be closer to a central portion of the one lens surface  22  while continuing to the flat surface portion, and a concave surface portion which is formed in such a manner as not only to be closer to the central portion of the lens surface  22  while continuing to the swelling portion but also to be recessed at the central portion.  
         [0043]     In addition, a lens surface of the anomalous lens  10  which lies on a side thereof where the light that has entered the anomalous lens  10  exits therefrom is defined by a flat surface portion formed around a circumferential edge portion of the lens surface  23  and a swelling portion which is formed in such a manner as not only to swell towards a central portion of the lens surface  23  while continuing to the flat surface portion but also to be recessed at the central portion of the lens surface  23 .  
         [0044]     The anomalous lens  10  is disposed such that the lens surface  22  faces the light exiting opening  15  of the reflector  13  of the light source  9 . In addition, the anomalous lens  10  is disposed such that the center of the lens surface  22  and the center of the lens surface  23  are situated on the optical axis K.  
         [0045]     The shape of the lens surface  22  of the anomalous lens  10  which lies on the side thereof which faces the light source  9  and the shape of the lens surface  23  of the anomalous lens  10  which lies on the side thereof which faces a primary reflecting mirror  11  are represented by an equation in which values shown in Table 2 are substituted for parameters in an equation (2) below.  
             (     Equation   ⁢             ⁢             ⁢   2     )                           z   =         cr   2       1   +       1   -       (     1   +   k     )     ⁢     c   2     ⁢     r   2               +       c   1     ⁢   r     +       c   2     ⁢     r   2       +       c   3     ⁢     r   3       +       c   4     ⁢     r   4       +       c   5     ⁢     r   5       +       c   6     ⁢     r   6                 (   2   )             
 
                                             TABLE 2                                   Lens Surface 22   Lens surface 23                                        Conic Constant: k   −1   −1           Radius of   Infinity   Infinity           curvature: c           Coefficient: c1   −1.903990E+00    1.030861E+00           Coefficient: c2    5.644817E−01   −1.438065E−01           Coefficient: c3   −7.786002E−02    1.668033E−03           Coefficient: c4    3.171810E−03   −3.641771E−05           Coefficient: c5    1.292878E−04    2.168144E−05           Coefficient: c6   −8.421956E−06   −5.061780E−07                      
 
         [0046]     where, z denotes an axis in the direction of the optical axis (a direction in which light travels is regarded as positive), c denotes a radius of curvature, and k denotes a Conic constant. In addition, r(mm) is the length of a perpendicular from a point V, which is a point on an edge portion of the anomalous lens  10 , to a point W where the perpendicular intersects the optical axis K when the perpendicular is drawn from the point V to the optical axis K as shown in  FIG. 6 .  
         [0047]     The lens surface  22  of the anomalous lens  10  which lies on the side thereof which faces the light source  9  can be separated into a range which collects light shone on to the lens surface  22  and guides the light so collected to the lens surface  23  which lies on the side of the anomalous lens  10  which faces the primary reflecting mirror  11  (hereinafter, referred to as an effective range  24 ) and the other range. In the case of an anomalous lens having a radius of 12.5 mm, the effective range  24  ranges from the outside of a range of a radius of 0.5 mm from the optical axis K to the inside of a range of a radius of 11 mm from the optical axis, as is shown in  FIG. 7 . In addition, a distance from a central point X to a point Y where the optical axis K intersects the lens surface  23  is 4 mm.  
         [0048]     As is shown in FIGS.  1  to  3 , the primary reflecting mirror  11  is disposed in a direction in which light exiting from the anomalous lens  10  travels for reflecting light that has so exited from the anomalous lens  10 . The primary reflecting mirror  11  is designed to reflect light that has exited from the anomalous lens  10  toward a spherical lens  12 .  
         [0049]      FIG. 8A  is a front view of a side of the spherical lens on to which light is shone, and  FIG. 8B  is a sectional view taken along the line b-b in  FIG. 8A . The spherical lens  12  has a lens surface  26  which is formed into a spherical shape on a side thereof where light is shone and a lens surface  29  which is formed into a flat shape on a side thereof where light is caused to exit. As is shown in  FIG. 8B , the spherical lens  12  is disposed such that a central point α of the lens surface  26  and a central point β of the lens surface  29  are situated on the optical axis K.  
         [0050]     The spherical lens  12  has a radius of 7.5 mm, for example, and as is shown in  FIG. 8A , in the lens surface  26 , a range lying inside a radius of 7 mm from the optical axis K constitutes a range for guiding light shone on to the lens surface  26  to the lens surface  29 .  
         [0051]     In addition, as is shown in  FIG. 8B , in the lens surface  26 , the central point α of the lens surface  26  is situated on the circumference of a circle σ having a radius of 14 mm which is centered at an imaginary point γ lying an extension of a line which connects the central point α of the lens surface  26  with the central point β of the lens surface  29  or on the optical axis K which lies on the side of the lens surface  29 , and the lens surface  26  is formed into a spherical surface which follows the circumference of the circle σ. In addition, the lens surface  29  is formed into the shape of a flat plate. A dimension from the central point α of the lens surface  26  with the central point β of the lens surface  29  is 4 mm.  
         [0052]     As is shown in FIGS.  1  to  3 , a color wheel  30  is disposed in a direction in which light exits from the spherical lens  12  for converting light that has exited from the spherical lens  12  into colors such as red (R), green (G) and blue (B). A mirror tunnel  31  is disposed in a traveling direction of light that has been transmitted through the color wheel  30 . Note that the color wheel  30  may be disposed on a side of the mirror tunnel  31  where light exits therefrom.  
         [0053]     The color wheel  30  is a circular rotary plate and includes red (R), green (G) and blue (B) color filters. The color wheel  30  is disposed such that a rotational axis thereof is offset to a side of the optical axis K.  
         [0054]     The mirror tunnel  31  is a transparent prism and is provide in such a manner as to extend along the optical axis K. A light entering surface or incident surface  31   a  on which light is incident is a rectangular surface, whose inside shorter side is 4.96 mm and inside longer side is 6.18 mm. The mirror tunnel  31  is designed to guide incident light from the incident surface  31   a  in the direction of the optical axis while totally reflecting the light on an interface between a side surface of the mirror tunnel  31  and a layer of outside air and to cause the light to exit from a light exiting surface  31   b  as a luminous flux of a uniform intensity distribution. Note that an angular tube may be used as the mirror tunnel  31  which has a reflecting coating provided on the whole of an inner circumferential surface thereof and whose outside shorter side is 4.96 mm and outside longer side is 6.18 mm.  
         [0055]     As is shown in  FIGS. 1 and 2 , an image projecting unit  32  is disposed in a direction in which light is caused to exit from the mirror tunnel  31 . As is shown in  FIG. 2 , the image projecting unit  32  is made up of, for example, a primary condenser lens  33  on to which light that has exited from the mirror tunnel  31  is shone, a secondary reflecting mirror  34  for reflecting light projected from the primary condenser lens  33 , a secondary condenser lens  35  for collecting light reflected by the secondary reflecting mirror  34 , a tertiary reflecting mirror  36  for reflecting light projected from the secondary condenser lens  35 , a meniscus lens  39  on to which light reflected by the tertiary reflecting mirror  36  is projected, a micromirror device  40  on to which light that has exited from the meniscus lens  39  is shone, and a projection lens  41  on to which light reflected by the mircromirror device  40  is projected.  
         [0056]     The primary condenser lens  33  is such as to project light that has exited from the mirror tunnel  31  on to the secondary reflecting mirror  34 . In  FIG. 2 , while illustrated as a singlet lens, the primary condenser lens  33  may be made up of a plurality of lenses.  
         [0057]     The secondary reflecting mirror  34  is such as to reflect light projected from the primary condenser lens  33  so as to project the light on to the secondary condenser lens  35 .  
         [0058]     The secondary condenser lens  35  is such as to collect light reflected by the secondary reflecting mirror  34  so as to project the light on to the tertiary reflecting mirror  36 . In  FIG. 2 , while illustrated as a singlet lens, the secondary condenser lens  35  may be made up of a plurality of lenses.  
         [0059]     The tertiary reflecting mirror  36  is disposed to reflect light projected from the secondary condenser lens  35  so as to project the light on to the meniscus lens  39 .  
         [0060]     The meniscus lens  39  is disposed such that light projected from the tertiary reflecting mirror is projected on to a concave surface side thereof. The meniscus lens  39  is disposed in such a position that light reflected by the mircromirror device  40  is collected so as to be projected on to the projection lens  41 . The meniscus lens  39  is disposed such that a convex surface thereof is made to face the micromirror device  40  while the concave surface is made to face the projection lens  41 .  
         [0061]     The mircromirror device  40  is such as to form each of pixels of an image to be displayed by a plurality of micromirrors and changing the brightness of each pixel by changing the inclination of those micromirrors. The micromirror is formed of an extremely thin metallic piece such as an aluminum piece, and the length and width thereof range from 10 μm to 20 μm. These micromirrors are provided on a plurality of mirror driving devices (not shown) such as CMOS which are arranged and formed in rows and columns into a matrix.  
         [0062]     In addition, light reflected from the micromirror device  40  is designed to be projected on to the projection lens  41  after having been transmitted through the meniscus lens  39 .  
         [0063]     The projection lens  41  is such as to enlarge light reflected from the micromirror device  40  so as to project the light on to a screen (not shown). Note that while illustrated as a singlet lens in  FIG. 2 , the projection lens  41  may be made up of a plurality of lenses.  
         [0064]     The function of the embodiment of the invention will be described below.  
         [0065]     When the projector system  1  is activated, light is radiated from the bulb  19  of the light source  9 , and most of the light so radiated is shone on to the mirror-finished inner wall of the reflector  13 .  
         [0066]     As this occurs, as is shown in  FIG. 3 , the bulb  19  of the light source  9  is designed to form a circle in the vicinity of the lamp accommodating opening  16  in which the position of a focal point (ST) of the radiated light which is radiated from the bulb  19  and reflected by the inner wall of the reflector  13  is positioned between the electrode introducing portion  20  and the light collecting surface of the anomalous lens  10  and which is centered at the optical axis K. Due to this, most of the reflected light is shone on to the other portion than the central portion of the lens surface  22  of the anomalous lens  10 . Of the light shone on to the lens surface  22  of the anomalous lens  10 , light shone on to the effective range  24  thereof is shone from the lens surface  23  on to the primary reflecting mirror  11  after having been collected.  
         [0067]     The light shone on to the primary reflecting mirror  11  is reflected thereon to thereby be shone on to the spherical lens  12 . The light shone on to the spherical lens  12  is collected to be shone on to the color wheel  30  thereafter. The light shone on to the color wheel  30  is converted into three colors such as red (R), green (G) and blue (B) by the red (R), green (G) and blue (B) filters provided on the color wheel  30 , and thereafter, the light so converted is then shone on to the incident surface  31   a  of the mirror tunnel  31 . The light that has entered the inside of the mirror tunnel  31  is guided in the direction of the optical axis while being totally reflected on the interface between the inner side surface of the mirror tunnel  31  and the layer of outside air as shown in  FIG. 3 , and the light is shone on to the primary condenser lens  33  after having exited from the exiting surface  31 b of the mirror tunnel  31  as shown in  FIG. 2 .  
         [0068]     The light shone on to the primary condenser lens  33  is reduced in expansion of the luminance flux thereof by the primary condenser lens  33  and is thereafter shone on to the secondary reflecting mirror  34 . The light shone on to the secondary reflecting mirror is shone on to the secondary condenser lens  35  to thereby be collected and thereafter is shone further on to the tertiary reflecting mirror  36 .  
         [0069]     The light shone on to the tertiary reflecting mirror  36  is shone on to the meniscus lens  39  and thereafter is shone on to the micromirror device  40 . Then, the light reflected by the micromirror device  40  is expanded by the projection lens  41  so as to be projected on to the screen (not shown).  
         [0070]     Thus, according to the invention, since the position of the focal point (ST) of the radiated light radiated from the bulb  19  and reflected by the reflector  13  is not situated at the electrode introducing portion  20 , most of the radiated light impinges on the electrode introducing portion  20  of the lamp in no case. Due to this, light reflected by the reflector  13  is shone on to the anomalous lens  10  without being dampened, thereby making it possible to reduce the loss of radiated light. Consequently, the utilization efficiency of radiated light radiated from the light source  9  can be increased, and this enables the reflector  13  to be made smaller in size, thereby making it possible to make the whole light source unit  6  smaller in size, compared to the conventional light source unit.  
         [0071]     In addition, since the light source unit  6  is made smaller in size, the projector system  1  itself which installs thereon the light source unit  6  can be made smaller in size. Additionally, by disposing the spherical lens  12  between the anomalous lens  10  and the mirror tunnel  31  the position of the focal point of light that has exited from the anomalous lens  10  can be adjusted, thereby making it possible to increase the degree of freedom in designing the light source unit  6  and the projector system  1 .  
       Second Embodiment  
       [0072]     Next, another embodiment of the invention will be describe by reference to the accompanying drawings. Note that the description of parts of the second embodiment which are common on the first embodiment will be omitted, and hence, parts which are different from the first embodiment will mainly be described.  
         [0073]      FIG. 9  is a plan view showing an interior of a projector system according to the second embodiment of the invention.  FIG. 10  is a schematic diagram showing the configuration of an optical system of the projector system according to this embodiment.  FIG. 11  is a schematic sectional view of a light source unit.  
         [0074]     As is shown in  FIG. 9 , a power supply substrate  52  for controlling the whole of a projector system  50  on which a power supply, not shown, is mounted is disposed in an interior of a case  51  of the projector system  50 . A light source unit  53 , which is controlled by the power supply substrate  52 , is disposed in the vicinity of a central portion in the case  51 .  
         [0075]     As is shown in  FIGS. 9 and 10 , the light source unit  53  is made up of a light source  9 , an anomalous lens  10  and a spherical lens  12 . As is shown in  FIG. 10 , the light source  9  is made up of a reflector  13  and a lamp  14  which is accommodated in the reflector  13 .  
         [0076]     In addition, as is shown in  FIG. 11 , a light exiting opening  15  from which light is caused to exit is provided in the reflector  13 . Furthermore, a lamp accommodating opening  16  is also provided in a proximal portion of the reflector  13 , so that the lamp  14  is accommodated from the lamp accommodating opening  16 .  
         [0077]     The anomalous lens  10  is disposed in a traveling direction of light that has exited from the light exiting opening  15 . There is imposed no limitation on the shape of the anomalous lens  10 , provided that the anomalous lens  10  can collect sufficiently light that has exited from the light exiting opening  15  so as to cause the light to exit in the light traveling direction.  
         [0078]     As is shown in  FIGS. 9 and 10 , the spherical lens  12  is disposed in a traveling direction of light that has exited from the anomalous lens  10 . A color wheel  30  is disposed in a traveling direction of light that has exited from the spherical lens  12  for converting light that has exited from the spherical lens  12  into colors such as red (R), green (G) and blue (B). A mirror tunnel  31  is disposed in a traveling direction of light that has exited from the color wheel  30 , and an image projecting unit  54  is disposed in a traveling direction of light that has exited from the mirror tunnel  31  for projecting an image on to a screen. Note that the color wheel  30  may be disposed to a light exiting side of the mirror tunnel  31 .  
         [0079]     As is shown in  FIGS. 9 and 10 , the image projecting unit  54  is disposed in a direction in which light is caused to exit from the mirror tunnel  31 . As is shown in  FIG. 10 , the image projecting unit  54  is made up of, for example, a primary condenser lens  33  on to which light that has exited from the mirror tunnel is shone, a tertiary reflecting mirror  36  on to which light that has exited from the primary condenser lens  33  is shone, a meniscus lens  39  on to which light that has been reflected from the tertiary reflecting mirror  36  is projected, a micromirror device  40  on to which light that has exited from the meniscus lens  39  is shone, and a projection lens  41  on to which light that has been reflected by the micromirror device  41  is projected.  
         [0080]     As is shown in  FIG. 9 , a sirocco fan  55  is disposed between the case  51  and the mirror tunnel  31  for supplying cooling air into the light source  9  so as to cool the light source  9 . In addition, an axial fan  56  is disposed to a side of the reflector  13  where the lamp accommodating opening  16  is provided for discharging air supplied into the light source  9  from the inside of the case  51 .  
         [0081]     Here, an example of a positional relationship of the light source unit  53  utilized in this embodiment by reference to  FIG. 12 . Note that dimensions of the reflector, the lamp and the anomalous lens are those which have been illustrated above therefor.  
         [0082]     An arc  21  resides on an optical axis K, and a distance from the arc  21  to an intersection point E between a reflecting surface origin of the reflector  13  which is situated on a proximal portion side of the reflector on the optical axis K and the optical axis K is 5.5 mm. The anomalous lens  10  is disposed such that a central point X of a lens surface  22  of the anomalous lens  10  which lies to face the light source  9  which is situated on the optical axis K is situated a distance of 39.5 mm apart from the intersection point E.  
         [0083]     In addition, the spherical lens  12  is disposed such that a central point α of a lens surface  26  of the spherical lens  12  which lies to face the anomalous lens  10  which is situated on the optical axis K is situated a distance of 25.5 mm apart from the central point X of the lens surface  22  of the anomalous lens  10 . Additionally, the mirror tunnel  31  is disposed such that a distance from the central point α of the lens surface  26  of the spherical lens  12  which lies to face the anomalous lens  10  to a point H where an incident surface  31   a  intersects the optical axis K at right angles becomes 10.74 mm.  
         [0084]     Next, the function of the embodiment will be described.  
         [0085]     When the projector system  50  is activated, light is radiated from a bulb  19  of the light source  9 , and most of the light so radiated is shone on to a mirror-finished inner wall of the reflector  13 .  
         [0086]     As this occurs, as is shown in  FIG. 11 , since the bulb  19  of the light source  9  is designed to form a circle in the vicinity of the lamp accommodating opening  16  in which the position of a focal point (ST) of the radiated light which is radiated from the bulb  19  and reflected by the inner wall of the reflector  13  is positioned between an electrode introducing portion  20  and the light collecting surface of the anomalous lens  10  and which is centered at the optical axis K, most of the reflected light is shone on to the other portion than the central portion of the lens surface  22  of the anomalous lens  10 . Of the light shone onto the lens surface  22  of the anomalous lens  10 , light shone on to an effective range  24  thereof is shone from a lens surface  23  on to the spherical lens  12  after having been collected.  
         [0087]     The light shone on to the spherical lens  12  is collected to thereby be shone on to he color wheel  30 .  
         [0088]     The light shone on to the color wheel  30  is converted into three colors such as red (R), green (G) and blue (B) by a red (R), green (G) and blue (B) filters provided on the color wheel  30 , and thereafter, the light so converted is then shone on to the incident surface  31   a  of the mirror tunnel  31 . The light that has entered the inside of the mirror tunnel  31  is guided in the direction of the optical axis while being totally reflected on an interface between an inner side surface of the mirror tunnel  31  and a layer of outside air as shown in  FIG. 11 , and the light is shone on to the primary condenser lens  33  after having exited from an exiting surface  31   b  of the mirror tunnel  31  as shown in  FIG. 10 .  
         [0089]     The light shone on to the primary condenser lens  33  is reduced in expansion of the luminance flux thereof by the primary condenser lens  33  and is thereafter shone on to the tertiary reflecting mirror  36 . The light shone on to the tertiary reflecting mirror  36  is shone on to the meniscus lens  39  and thereafter is shone on to the micromirror device  40 . Then, the light reflected by the micromirror device  40  is expanded by the projection lens  41  so as to be projected on to a screen, not shown.  
         [0090]     Thus, according to the invention, since the position of the focal point (ST) of the radiated light radiated from the bulb  19  and reflected by the reflector  13  is not situated at the electrode introducing portion  20 , most of the radiated light impinges on the electrode introducing portion  20  of the lamp in no case. Due to this, light reflected by the reflector  13  is shone on to the lens without being dampened, thereby making it possible to reduce the loss of radiated light. Consequently, since the utilization efficiency of radiated light radiated from the light source  9  can be increased, the reflector  13  is enabled to be made smaller in size, thereby making it possible to make the whole light source unit  53  smaller in size, compared to the conventional light source unit.  
         [0091]     In addition, since the light source unit  53  is made smaller in size, the projector system  50  itself which installs thereon the light source unit  53  can be made smaller in size. Additionally, by disposing the spherical lens  12  between the anomalous lens  10  and the mirror tunnel  31  the position of the focal point of light that has exited from the anomalous lens  10  can be adjusted, thereby making it possible to increase the degree of freedom in designing the light source unit  6  and the projector system  1 .