Abstract:
The entrance region of this light flux control member has second protruding strips disposed at the edges of a virtual quadrangle, and angle parts disposed at the four corners of the virtual quadrangle. The angle parts having a third entrance face, and a third reflective face establishing a connection between two neighboring second reflective faces. The height of a third crest line at the boundary between the third entrance face and the third reflective face decreases gradually as a diagonal line of the virtual quadrangle is approached. The distance between the outermost edge of the third reflective face and the third crest line decreases gradually as the diagonal line of the virtual quadrangle is approached. The distance between the extremities of a second crest line of the second protruding strip is shorter than the distance between the extremities of a first crest line located most outward.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a light flux controlling member that controls the distribution of light emitted from a light emitting element. The present invention also relates to a light-emitting device and an illumination apparatus having the light flux controlling member. 
       BACKGROUND ART 
       [0002]    In recent years, for the purpose of energy saving and downsizing, light-emitting devices (LED flash) using a light-emitting diode (hereinafter referred to as “LED”) as the light source have been increasingly used as a light-emitting device for an image pickup camera. A well-known example of such light emitting devices is a light emitting device using a combination of an LED and a fresnel lens. 
         [0003]    In general, the imaging region of an imaging camera is square. Therefore, a light-emitting device preferably illuminates the illumination region in a square shape to obtain clear captured image. In view of this, desirably, a fresnel lens used in a light-emitting device for an imaging camera uniformly and efficiently illuminates a square illumination region with light emitted from a light emitting element. Conventionally, various fresnel lenses for illuminating a square illumination region have been proposed (see, for example, PTL 1). 
         [0004]      FIG. 1A  is a perspective view of fresnel lens  10  disclosed in PTL 1. Fresnel lens  10  illustrated in  FIG. 1A  can provide a function same as that of cylindrical lens  20  illustrated in  FIG. 1B . As illustrated in  FIG. 1A , in fresnel lens  10  disclosed in PTL 1, a plurality of rectangular grooves  12  are concentrically disposed with a space therebetween in plan view. 
       CITATION LIST 
     Patent Literature 
     PTL 1 
     Japanese Patent Application Laid-Open No. 11-065490 
     SUMMARY OF INVENTION 
     Technical Problem 
       [0005]    However, when a square illumination region is illuminated with light with use of the fresnel lens disclosed in PTL 1, the square illumination region cannot be sufficiently or uniformly illuminated with the light emitted from the light emitting element in an efficient manner, and for this reason the fresnel lens disclosed in PTL 1 has a room for improvement. 
         [0006]    An object of the present invention is to provide a light flux controlling member which can uniformly and efficiently illuminate a square illumination region with light emitted from a light emitting element. In addition, an object of the present invention is to provide a light-emitting device and an illumination apparatus including the light flux controlling member. 
       Solution to Problem 
       [0007]    A light flux controlling member of the present invention is configured to control distribution of light emitted from a light emitting element, the light flux controlling member including: an incidence region on which the light emitted from the light emitting element is incident; and an emission region formed on a side opposite to the incidence region, and configured to emit light incident on the incidence region, in which the incidence region includes: a fresnel lens section including a plurality of first projected lines, each first projected line including a first incidence surface on which a part of the light emitted from the light emitting element is incident, a first reflecting surface paired with the first incidence surface and configured to reflect incident light toward the emission region, and a first ridgeline configured to join adjacent two diagonals of a first virtual square, and an outermost lens section including four second projected lines and corner portions, each second projected line including a second incidence surface on which another part of the light emitted from the light emitting element is incident, and a second reflecting surface paired with the second incidence surface and configured to reflect incident light toward the emission region, each second projected line being disposed on a side of a second virtual square disposed outside the first virtual square, each corner portion being disposed at one of four corners of the second virtual square and configured to connect adjacent two second projected lines of the four second projected lines to join the second projected lines; the first virtual square and the second virtual square are similar to each other, and are concentrically disposed such that sides thereof are parallel to each other; the incidence region is two-fold rotational symmetry or four-fold rotational symmetry around a center of the first virtual square and a center of the second virtual square as a rotational axis; the corner portion is a part of a substantially conical member whose vertex is located on a center side of the second virtual square, the corner portion including a third reflecting surface and a third incidence surface which correspond to side surfaces of the substantially conical member, the third reflecting surface being configured to connect the two adjacent second reflecting surfaces to join the second reflecting surfaces, the third incidence surface being paired with the third reflecting surface and being a surface on which still another part of the light emitted from the light emitting element section is incident; a third ridgeline formed at a connecting part between the third incidence surface and the third reflecting surface has a height which gradually decreases toward a diagonal of the second virtual square; an interval between an outermost edge of the third reflecting surface and the third ridgeline gradually decreases toward the diagonal of the second virtual square in plan view of the incidence region; and an end-to-end distance of a second ridgeline of the second projected line is smaller than an end-to-end distance of the first ridgeline of the first projected line located at an outermost position. 
         [0008]    A light-emitting device of the embodiments of the present invention comprising: a light emitting element; and the light flux controlling member, in which the light flux controlling member is disposed such that an optical axis of the light emitting element passes through a center of the second virtual square, and the second ridgeline has a length greater than a maximum size of the light emitting element in an extending direction of the second projected line. 
         [0009]    An illumination apparatus of the embodiments of the present invention includes: the light-emitting device; and a cover configured to allow the light emitted from the light-emitting device to pass therethrough while diffusing the light. 
       Advantageous Effects of Invention 
       [0010]    In comparison with a light-emitting device having a conventional light flux controlling member, the light-emitting device having the light flux controlling member of the embodiments of the present invention can uniformly and efficiently illuminate a square illumination region. Therefore, the illumination apparatus of the embodiments of the present invention causes less luminance unevenness in comparison with the conventional illumination apparatus. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]      FIGS. 1A and 1B  illustrate a configuration of a fresnel lens disclosed in PTL 1; 
           [0012]      FIG. 2  is a sectional view of a light-emitting device according to Embodiment 1; 
           [0013]      FIG. 3  is a perspective view of a light flux controlling member according to Embodiment 1; 
           [0014]      FIGS. 4A to 4C  illustrate a configuration of the light flux controlling member according to Embodiment 1; 
           [0015]      FIGS. 5A and 5B  are bottom views of the light flux controlling member according to Embodiment 1 in which a refraction section, a fresnel lens section and a reflection section are omitted; 
           [0016]      FIGS. 6A and 6B  are sectional views of the light flux controlling member according to Embodiment 1; 
           [0017]      FIG. 7  is a drawing for describing installation positions of a second projected line and a corner portion; 
           [0018]      FIGS. 8A to 8C  are drawings for describing the stereoscopic shape of the corner portion; 
           [0019]      FIGS. 9A and 9B  are drawings for describing the stereoscopic shape of the corner portion; 
           [0020]      FIG. 10  is a perspective view of a light flux controlling member for comparison; 
           [0021]      FIGS. 11A to 11C  show simulation of the illuminance distribution using a light-emitting device having the light flux controlling member for comparison; 
           [0022]      FIGS. 12A to 12C  show simulation of the illuminance distribution using a light-emitting device having the light flux controlling member according to Embodiment 1; 
           [0023]      FIG. 13  illustrates a configuration of an illumination apparatus according to Embodiment 1; 
           [0024]      FIGS. 14A and 14B  are bottom views of a light flux controlling member according to a modification of Embodiment 1; 
           [0025]      FIG. 15  is a perspective view of a light flux controlling member according to Embodiment 2; 
           [0026]      FIG. 16  is a perspective view of a light flux controlling member according to Embodiment 3; 
           [0027]      FIGS. 17A to 17C  illustrate a configuration of the light flux controlling member according to Embodiment 3; 
           [0028]      FIGS. 18A and 18B  are sectional views of the light flux controlling member according to Embodiment 3; 
           [0029]      FIG. 19  is a perspective view of a light flux controlling member according to a first modification of Embodiment 3; 
           [0030]      FIGS. 20A to 20C  illustrate a configuration of the light flux controlling member according to the first modification of Embodiment 3; 
           [0031]      FIGS. 21A and 21B  are sectional views of the light flux controlling member according to the first modification of Embodiment 3; 
           [0032]      FIG. 22  is a perspective view of a light flux controlling member according to a second modification of Embodiment 3; 
           [0033]      FIGS. 23A to 23C  illustrate a configuration of the light flux controlling member according to the second modification of Embodiment 3; 
           [0034]      FIGS. 24A and 24B  are sectional views of the light flux controlling member according to the second modification of Embodiment 3; 
           [0035]      FIG. 25  is a perspective view of a light flux controlling member according to Embodiment 4; 
           [0036]      FIGS. 26A to 26C  illustrate a configuration of the light flux controlling member according to Embodiment 4; and 
           [0037]      FIGS. 27A and 27B  are sectional views of the light flux controlling member according to Embodiment 4. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0038]    In the following, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
       Embodiment 1 
     Configurations of Light Flux Controlling Member and Light-Emitting Device 
       [0039]      FIG. 2  is a sectional view of light-emitting device  100  according to Embodiment 1 of the present invention. As illustrated in  FIG. 2 , light-emitting device  100  includes light emitting element  120  and light flux controlling member  140 . Light emitting element  120  is a light-emitting diode (LED) such as a white light-emitting diode, for example. Light flux controlling member  140  controls the distribution of the light emitted from light emitting element  120 . Light flux controlling member  140  is disposed in such a manner that its central axis CA coincides with optical axis LA of light emitting element  120 . 
         [0040]    The material of light flux controlling member  140  is not specifically limited as long as the light having desired wavelengths can pass through light flux controlling member  140 . Examples of the material of light flux controlling member  140  include: light transmissive resins such as polymethylmethacrylate (PMMA), polycarbonate (PC), and epoxy resin (EP); and glass. Light flux controlling member  140  can be manufactured by injection molding, for example. 
         [0041]      FIG. 3  to  FIG. 7  illustrate a configuration of light flux controlling member  140  according to Embodiment 1.  FIG. 3  is a perspective view of light flux controlling member  140  according to Embodiment 1.  FIGS. 4A to 4C  are a plan view, a bottom view, and a side view of light flux controlling member  140 , respectively.  FIG. 5A  is a bottom view of light flux controlling member  140  illustrating only first virtual square S 1 , and  FIG. 5B  is a bottom view of light flux controlling member  140  illustrating only first virtual square S 1  and second virtual square S 2 .  FIG. 6A  is a sectional view taken along line A-A of  FIG. 4B , and  FIG. 6B  is a partially enlarged sectional view of a region denoted with the broken line in  FIG. 6A .  FIG. 7  is a drawing for describing installation positions of second projected line  171  and corner portion  172 . 
         [0042]    As illustrated in  FIG. 3  to  FIG. 7 , light flux controlling member  140  includes incidence region  141  on which light emitted from light emitting element  120  is incident, and emission region  142  provided on the side opposite to incidence region  141  and configured to output the light incident on incidence region  141 . Flange  143  may be provided between incidence region  141  and emission region  142 . 
         [0043]    The shape of light flux controlling member  140  in plan view is not limited. As illustrated in  FIG. 4A , light flux controlling member  140  according to the present embodiment has a square shape in plan view. In addition, the length of one side of light flux controlling member  140  of the present embodiment is about 4.7 mm, for example. 
         [0044]    Light emitted from light-emitting elements  120  is incident on incidence region  141 . Incidence region  141  includes refraction section  150  provided at a center portion of incidence region  141 , fresnel lens section  160  provided outside refraction section  150 , and outermost lens section  170  provided outside fresnel lens section  160 . Incidence region  141  is two-fold rotational symmetry or four-fold rotational symmetry around the center of first virtual square S 1  and the center of second virtual square S 2  described later as a rotational axis. The rotational axis coincides with central axis CA of light flux controlling member  140  and optical axis LA of light emitting element  120 . Accordingly, incidence region  141  is two-fold rotational symmetry or four-fold rotational symmetry around central axis CA of light flux controlling member  140  and optical axis LA of light emitting element  120 . The external shape of incidence region  141  is rectangular or square, for example. 
         [0045]    Refraction section  150  allows part of light emitted from light emitting element  120  (light emitted at a small angle with respect to optical axis LA) to enter light flux controlling member  140 , and refracts the incident light toward emission region  142 . Refraction section  150  is disposed at a position facing light emitting element  120  in such a manner as to intersect with central axis CA of light flux controlling member  140  (optical axis LA of light emitting element  120 ) (see  FIG. 2 ). As long as refraction part  150  can have the above-mentioned function, the shape of refraction part  150  is not limited. For example, refraction section  150  may have a shape of a refractive fresnel lens. In addition, the surface of refraction section  150  may be a spherical surface or an aspherical surface. In the present embodiment, the surface of refraction section  150  is an aspherical surface, and the shape of refraction section  150  is a substantially square pyramid shape (see  FIGS. 2 and 3 ). 
         [0046]    Fresnel lens section  160  allows part of light emitted from light emitting element  120  (light emitted at a relatively large angle with respect to optical axis LA) to enter light flux controlling member  140 , and reflects the incident light toward emission region  142 . Fresnel lens section  160  includes a plurality of first projected lines  161  configured to control the travelling direction of light emitted from light emitting element  120 . 
         [0047]    As illustrated in  FIG. 5A , it is assumed that first virtual square S 1  is disposed in fresnel lens section  160 . Center O 1  (the intersection of diagonals L 1 ) of first virtual square S 1  coincides with central axis CA of light flux controlling member  140 . First virtual square S 1  and four diagonals L 1  serve as references for disposing first projected lines  161 . First projected lines  161  are disposed to join adjacent two diagonals L 1 . First projected lines  161  may have a straight shape or a curved shape. In addition, first projected lines  161  are disposed to form a valley part between adjacent two first projected lines  161  in a region between adjacent two diagonals L 1  (see  FIG. 6B ). 
         [0048]    The shape and the size of first projected line  161  are not limited, and may be identical to one another, or different from one another. In the present embodiment, the sizes of first projected lines  161  are different from one another (see  FIG. 6B ). In addition, in the optical axis LA direction, distance d (distance d from the reference surface to first ridgeline  165 ) between the lower end of light flux controlling member  140  and first ridgeline  165  of each first projected line  161  gradually decreases toward the outer side from the inner side (see  FIG. 6B ). Here, the “lower end of light flux controlling member  140 ” means the apex of second projected line  171  (second ridgeline  176 ) described later, and the “reference surface” means a plane including the apex of second projected line  171  (second ridgeline  176 ). 
         [0049]    First projected line  161  includes first incidence surface  162 , first reflecting surface  163 , first connection surface  164  and first ridgeline  165 . In first projected line  161 , first incidence surface  162  is disposed on the inner side (central axis CA side), and first reflecting surface  163  is disposed on the outer side (see  FIG. 6B ). 
         [0050]    Part of light emitted from light emitting element  120  is incident on first incidence surface  162 , and first incidence surface  162  refracts the light to first reflecting surface  163  side. First incidence surface  162  may be a planar surface or a curved surface. In the present embodiment, first incidence surface  162  is a planar surface. In addition, first incidence surface  162  may be parallel to central axis CA (optical axis LA of light emitting element  120 ), or may be tilted with respect to central axis CA. In the present embodiment, for the purpose of facilitating the releasing, first incidence surface  162  is tilted such that the distance from central axis CA increases toward the lower end (reference surface) of light flux controlling member  140 . Preferably, the inclination angle of first incidence surface  162  is greater than 0 degree, and equal to or smaller than 10 degrees with respect to central axis CA in any cross-section including central axis CA. The inclination angle of first incidence surface  162  is preferably 5 degrees or smaller, more preferably 3 degrees or smaller. 
         [0051]    First reflecting surface  163  is paired with first incidence surface  162 , and configured to reflect the light incident on first incidence surface  162  toward emission region  142 . First reflecting surface  163  may be a planar surface or a curved surface. In the present embodiment, first reflecting surface  163  is a planar surface. In addition, for the purpose of totally reflecting the light that has reached first reflecting surface  163 , first reflecting surface  163  is tilted with respect to central axis CA. First reflecting surface  163  is tilted such that the distance to central axis CA decreases toward the lower end (reference surface) of light flux controlling member  140 . 
         [0052]    First connection surface  164  joins first incidence surface  162  and first reflecting surface  163 . First connection surface  164  may be a planar surface, or a curved surface. In the present embodiment, first connection surface  164  is a planar surface. In addition, it is also possible to directly join first incidence surface  162  and first reflecting surface  163  without forming first connection surface  164 . 
         [0053]    First ridgeline  165  is a boundary line between first incidence surface  162  and first connection surface  164 . First ridgeline  165  is disposed to join adjacent two diagonals L 1  of first virtual square S 1 . It is to be noted that, when first connection surface  164  not formed, first ridgeline  165  is a boundary line between first incidence surface  162  and first reflecting surface  163 . When first connection surface  164  is provided between first incidence surface  162  and first reflecting surface  163 , the manufacturing performance can be enhanced by eliminating an acute angle portion. In plan view of incidence region  141 , first ridgeline  165  may be a straight line, or a curved line. In the present embodiment, in plan view of incidence region  141 , first ridgeline  165  is a straight line. 
         [0054]    Outermost lens section  170  allows part of light emitted from light emitting element  120  (light emitted at a large angle with respect to optical axis LA) to enter light flux controlling member  140 , and reflects the incident light toward emission region  142 . Outermost lens section  170  includes four second projected lines  171 , and four corner portions  172 . 
         [0055]    As illustrated in  FIG. 5B , it is assumed that second virtual square S 2  is disposed in outermost lens section  170 . Center O 2  (the intersection of second diagonals L 2 ) of second virtual square S 2  coincides with central axis CA of light flux controlling member  140 . Second virtual square S 2  serves as a reference for disposing four second projected lines  171  and four corner portions  172 . Second virtual square S 2  is disposed outside first virtual square S 1 . Second virtual square S 2  and first virtual square S 1  are similar to each other, and are concentrically disposed such that each side of second virtual square S 2  and first virtual square S 1  are parallel to each other. It is only necessary that first ridgeline  165  is disposed to join adjacent two diagonals L 1  of first virtual square S 1  as described above. Accordingly, first ridgeline  165  and second ridgeline  176  described later may be formed in curved lines, and therefore may not be parallel to each other. 
         [0056]    Four second projected lines  171  are disposed on respective sides of second virtual square S 2 . In the plane orthogonal to the side on which second projected line  171  is disposed, the cross-sectional area of second projected line  171  is greater than that of first projected line  161 . Both ends of second projected line  171  are connected with respective corner portions  172 . In the direction parallel to the side of second virtual square S 2 , the length of second projected line  171  is smaller than that of outermost first projected line  161 . When light flux controlling member  140  is used in the above-mentioned light-emitting device  100 , it is preferable that the length of second projected line  171  be greater than the width of light emitting element  120  used for light-emitting device  100  in the direction parallel to the side of second virtual square S 2 . 
         [0057]    Second projected line  171  is formed in a substantially triangular prism shape. In the plane orthogonal to the side on which second projected line  171  is disposed, the cross-sectional shape of second projected line  171  is a substantially triangular shape. Each second projected line  171  includes second incidence surface  173 , second reflecting surface  174 , second connection surface  175  and second ridgeline  176 . In second projected line  171 , second incidence surface  173  is disposed on the inner side (central axis CA side), and second reflecting surface  174  is disposed on the outer side (see  FIG. 6B ). 
         [0058]    Light emitted from light emitting element  120  is incident on second incidence surface  173 , and second incidence surface  173  refracts the incident light to second reflecting surface  174  side. Second incidence surface  173  may be a planar surface, or a curved surface. In the present embodiment, second incidence surface  173  is a planar surface. In addition, second incidence surface  173  may be parallel to central axis CA, or may be tilted with respect to central axis CA. In the present embodiment, for the purpose of facilitating the releasing, second incidence surface  173  is tilted such that the distance from central axis CA increases toward the lower end (reference surface) of light flux controlling member  140 . 
         [0059]    Second reflecting surface  174  is paired with second incidence surface  173 , and is configured to reflect the light incident on second incidence surface  173  toward emission region  142 . Second reflecting surface  174  may be a planar surface or a curved surface. In the present embodiment, second reflecting surface  174  is a curved surface. Second reflecting surface  174  is a straight line in cross-section (horizontal cross-section) orthogonal to central axis CA. In addition, second reflecting surface  174  is a curved line protruding outward in a cross-section (perpendicular cross-section) including central axis CA. 
         [0060]    Second connection surface  175  joins second incidence surface  173  and second reflecting surface  174 . Second connection surface  175  may be a planar surface or a curved surface. In the present embodiment, second connection surface  175  is a planar surface. In addition, it is also possible to directly join second incidence surface  173  and second reflecting surface  174  without forming second connection surface  175 . 
         [0061]    Second ridgeline  176  is a boundary line between second incidence surface  173  and second connection surface  175 . It is to be noted that, when second connection surface  175  is not formed, second ridgeline  176  is a boundary line between second incidence surface  173  and second reflecting surface  174 . When second connection surface  175  is provided between second incidence surface  173  and second reflecting surface  174 , manufacturing performance can be enhanced by eliminating an acute angle portion. In addition, as illustrated in  FIG. 7 , end-to-end distance d 1  of second ridgeline  176  is smaller than end-to-end distance d 2  of first ridgeline  165  of outermost first projected line  161 . In addition, when light flux controlling member  140  is used in the above-mentioned light-emitting device  100 , end-to-end distance d 1  of second ridgeline  176  is preferably greater than the width of light emitting element  120  used in light-emitting device  100 . 
         [0062]    Four corner portions  172  are respectively disposed at the four corners of second virtual square S 2 . Corner portion  172  is a part of a substantially conical member whose vertex is located on center O 2  side of second virtual square S 2 . Corner portion  172  includes third incidence surface  177 , third reflecting surface  178  and third ridgeline  179 . Here, the “substantially conical member (cone)” is a stereoscopic shape which is obtained by connecting the vertex and the outer peripheral edges of the bottom surface with a straight line or curved line. Examples of the substantially conical member (cone) include a pyramidal member, a substantially pyramidal member whose lines connecting the vertex and circumferential points of the bottom surface protrude outward, a substantially pyramidal member whose lines connecting the vertex and circumferential points of the bottom surface protrude inward, a conical member, a substantially conical member whose generatrix protrudes outward, and a substantially conical member whose generatrix protrudes inward. In the present embodiment, the substantially conical member (cone) is a substantially conical member whose generatrix protrudes outward. 
         [0063]    Still another part of the light emitted from light emitting element  120  is incident on third incidence surface  177 , and third incidence surface  177  refracts the light to third reflecting surface  178  side. Third incidence surface  177  may be a planar surface or a curved surface. In the present embodiment, third incidence surface  177  is composed of two planar surfaces. In addition, third incidence surface  177  may be parallel to central axis CA, or may be tilted with respect to central axis CA. In the present embodiment, for the purpose of facilitating the releasing, the two planar surfaces are tilted with respect to central axis CA. The two planar surfaces are tilted such that the distance from central axis CA increases toward the lower end (reference surface) of light flux controlling member  140 . The two planar surfaces of third incidence surface  177  may be flush with adjacent second incidence surface  173 . 
         [0064]    Third reflecting surface  178  is paired with third incidence surface  177 , and is configured to reflect the light incident on third incidence surface  177  toward emission region  142 . In the present embodiment, third reflecting surface  178  is a curved surface. In a cross-section (horizontal cross-section) orthogonal to central axis CA, the outer edge of third reflecting surface  178  is a curved line protruding outward. In addition, in a cross-section (perpendicular cross-section) including central axis CA, the outer edge of third reflecting surface  178  is a curved line protruding outward. Third reflecting surface  178  corresponds to a part of a side surface of a substantially conical member, and connects adjacent two second reflecting surfaces  174  to join two second reflecting surfaces  174 . 
         [0065]    Third ridgeline  179  is a boundary line between third incidence surface  177  and third reflecting surface  178 . As described later, third ridgeline  179  is a curved line which is formed such that the distance to emission region  142  gradually decreases toward second diagonal L 2  of second virtual square S 2  from second projected line  171  side. In addition, as illustrated in  FIG. 7 , distance d 3  between the outermost edge of third reflecting surface  178  and third ridgeline  179  gradually decreases toward diagonal L 2  of second virtual square S 2  in plan view of incidence region  141 . With this configuration, at a position where corner portion  172  and second diagonal L 2  of second virtual square S 2  intersect with each other, a recessed portion is formed. It is to be noted that the boundary between third incidence surface  177  and third reflecting surface  178  may be chamfered to form a connection surface (third connection surface). In this case, third ridgeline  179  is a boundary line between third incidence surface  177  and the third connection surface. 
         [0066]      FIGS. 8 and 9  are drawings for describing the stereoscopic shape of corner portion  172 . It is to be noted that  FIG. 8C  is a perspective view in the arrow direction of  FIG. 8B . As described above, corner portion  172  is a part of a substantially conical member (cone). Here, a substantially conical member having a circular bottom surface is assumed (see  FIG. 8A ). The substantially conical member is vertically cut by a cross having a predetermined width (see  FIGS. 8B and 8C ). At this time, the width of the cross is equal to the length of second projected line  171  in the direction of the side of second virtual square S 2 . Next, a center part of the substantially conical member is removed such that third incidence surface  177  is tilted in the above-mentioned fashion (see  FIGS. 9A and 9B ). At this time, the side surface of the substantially conical member is a curved surface, and therefore third ridgeline  179  is formed such that the distance to emission region  142  gradually decreases toward second diagonal L 2  of second virtual square S 2  from second projected line  171  side. It is to be noted that, in the present embodiment, each of third reflecting surfaces  178  of four corner portions  172  is a part of the side surface of one substantially conical member whose vertex is located on central axis CA of light flux controlling member  140  (central axis CA of light flux controlling member  140  and the central axis of the substantially conical member coincide with each other). However, four third reflecting surfaces  178  may be parts of side surfaces of substantially conical members having different central axes. 
         [0067]    Emission region  142  is a planar surface or a curved surface formed on a side nearer to the region to be illuminated, which is opposite to light emitting element  120  side. In the present embodiment, emission region  142  is a planar surface. Emission region  142  is formed to intersect with central axis CA of light flux controlling member  140  (see FIG.  2 ). The light which is incident on refraction section  150 , the light which is incident on first incidence surface  162  and reflected at first reflecting surface  163 , the light which is incident on second incidence surface  173  and reflected at second reflecting surface  174 , and the light which is incident on third incidence surface  177  and reflected at third reflecting surface  178  are emitted toward a region to be illuminated from emission region  142 . 
         [0068]    (Simulation) 
         [0069]    Simulation of the illuminance distribution was carried out in light-emitting device  100  having light flux controlling member  140  according to Embodiment 1. In addition, the illuminance distribution of a light-emitting device including light flux controlling member  140 ′ having no corner portion  172  illustrated in  FIG. 10  was also simulated for comparison. 
         [0070]      FIGS. 11A to 11C  show simulation of the illuminance distribution of the light-emitting device having light flux controlling member  140 ′ for comparison.  FIG. 11A  shows simulation of the illuminance distribution of light emitted via the entire light flux controlling member  140 ′ for comparison, and  FIGS. 11B and 11C  show simulation of the illuminance distribution of light emitted via only outermost lens section  170 ′. In  FIG. 11C , the sensitivity is increased in comparison with  FIG. 11B .  FIGS. 11A to 11C  show simulation of the illuminance distribution in an exemplary case where a region to be illuminated is separated from the light emitting surface of light emitting element  120  by 1000 mm (the same applies to  FIGS. 12A to 12C ). In  FIGS. 11A to 11C , the ordinate and the abscissa of the left diagrams indicate the distance (mm) from optical axis LA of light emitting element  120  (central axis CA of light flux controlling member  140 ′). In addition, the ordinate in the right diagrams indicates illuminance (lux). 
         [0071]    As illustrated in  FIG. 11A , it is recognized that light flux controlling member  140 ′ for comparison having no corner portion  172  also can illuminate the illumination region with light in a square to a certain degree. In addition, as illustrated in  FIG. 11B , it is recognized that the light via only outermost lens section  170 ′ reaches peripheral portions of the illumination region. However, when the light via only outermost lens section  170 ′ is analyzed in detail, it is recognized that light outward of the illumination region is generated at the four corners of light flux controlling member  140 ′ as illustrated in  FIG. 11C . 
         [0072]      FIGS. 12A to 12C  show simulation of the illuminance distribution in the case where light-emitting device  100  having light flux controlling member  140  according to Embodiment 1 is used.  FIG. 12A  shows simulation of the illuminance distribution of light emitted via the entire light flux controlling member  140  according to Embodiment 1, and  FIGS. 12B and 12C  show simulation of the illuminance distribution of light emitted via only outermost lens section  170 . In  FIG. 12C , the sensitivity is increased in comparison with  FIG. 12B . 
         [0073]    As illustrated in  FIG. 12A , it is recognized that light flux controlling member  140  according to the present embodiment having corner portions  172  can illuminate the illumination region in a square form. In addition, as illustrated in  FIG. 12B , it is recognized that the light via only outermost lens section  170  can illuminate the outline of the illumination region. Further, as illustrated in  FIG. 12C , the light outward of the illumination region is not generated at the four corners of light flux controlling member  140 . In view of the above, it can be said that light-emitting device  100  according to the present embodiment can uniformly illuminate the illumination region in comparison with the light-emitting device for comparison. Of the light emitted from light emitting element  120  toward corner portion  172 , the light that passes through the recessed portion of corner portion  172  is not influenced by the control of corner portion  172 , and travels to the illumination region without change. The amount of such uncontrolled light is small, and therefore a desired square-shaped illuminance distribution illustrated in  FIG. 12  can be obtained without forming bright spots or dark points on the illuminated surface. Consequently, even when a burr-like wall part which is parallel to central axis CA (optical axis LA of light emitting element  120 ) is formed from third ridgeline  179  at the recessed portion, an effect similar to that of light flux controlling member  140  of Embodiment 1 is obtained when the burr-like wall part has no light flux controlling function (a second modification of Embodiment 3, see  FIGS. 22 to 24 ). 
         [0074]    (Configuration of Illumination Apparatus) 
         [0075]    Next, illumination apparatus  400  having light-emitting device  100  according to the present embodiment will be described. 
         [0076]      FIG. 13  illustrates a configuration of illumination apparatus  400  according to the present embodiment. As illustrated in  FIG. 13 , illumination apparatus  400  includes light-emitting device  100  and cover  420 . As described above, light-emitting device  100  includes light flux controlling member  140  and light emitting element  120 . Light emitting element  120  is fixed to substrate  440 . 
         [0077]    Cover  420  allows the light emitted from light-emitting device  100  to pass therethrough while diffusing the light, and protects light-emitting device  100 . Cover  420  is disposed on the light path of the light emitted from light-emitting device  100 . As long as cover  420  can have the above-mentioned function, the material of cover  420  is not limited. Examples of the material of cover  420  include light transmissive resins such as polymethylmethacrylate (PMMA), polycarbonate (PC), and epoxy resin (EP); and glass. 
         [0078]    (Modification) 
         [0079]    A light-emitting device and an illumination apparatus according to a modification of Embodiment 1 are respectively different from light-emitting device  100  and illumination apparatus  400  according to Embodiment 1 in the shape of light flux controlling member  140 . Therefore, the same components as those of light-emitting device  100  and illumination apparatus  400  according to Embodiment 1 are denoted with the same reference numerals and the description thereof are omitted, and, the components different from light flux controlling member  140  will be mainly described. Light flux controlling member  540  according to the modification of Embodiment 1 is different from light flux controlling member  140  according to Embodiment 1 in the shape of first projected line  161 . 
         [0080]    (Configuration of Light Flux Controlling Member) 
         [0081]      FIGS. 14A and 14B  are bottom views of light flux controlling member  540  according to modifications of Embodiment 1 of the present invention.  FIG. 14A  is a bottom view of light flux controlling member  540  according to the modification 1 of Embodiment 1, and  FIG. 14B  is a bottom view of light flux controlling member  640  according to modification 2 of Embodiment 1. 
         [0082]    As illustrated in  FIG. 14A , incidence region  541  of light flux controlling member  540  according to the modification 1 of Embodiment 1 includes refraction section  150 , fresnel lens section  560  and outermost lens section  170 . Fresnel lens section  560  has a plurality of first projected lines  561  each including first incidence surface  562 , first reflecting surface  563 , first connection surface  564  and first ridgeline  565 . 
         [0083]    First incidence surface  562  is a curved surface. In a cross-section orthogonal to central axis CA (horizontal cross-section), the inner edge of first incidence surface  562  is a curve protruding toward central axis CA side. In addition, in a cross-section including central axis CA (vertical cross-section), first incidence surface  562  is tilted such that the distance from central axis CA increases toward the lower end of light flux controlling member  540  (reference surface). Although not illustrated in the drawings, in a cross-section including central axis CA (vertical cross-section), the inner edge of first reflecting surface  663  may be a curve. It is to be noted that, when the inner edge of first incidence surface  562  is a curve in a cross-section including central axis CA, the “angle of first incidence surface  562 ” is the angle of the tangent to first incidence surface  562  at a light incident point. 
         [0084]    First reflecting surface  563  is a curved surface. In a cross-section orthogonal to central axis CA (horizontal cross-section), the outer edge of first reflecting surface  563  is a curve protruding toward central axis CA side. In addition, in a cross-section including central axis CA (vertical cross-section), the outer edge of first reflecting surface  563  is a curve. When the outer edge of first reflecting surface  563  is a curve in a cross-section including central axis CA, the “angle of first reflecting surface  563 ” is the angle of the tangent to first reflecting surface  563  at a light incident point. 
         [0085]    First ridgeline  565  has an arc-like shape in plan view. The curvature radius of the arc (first ridgeline  565 ) is greater than the distance between the intersection of the diagonals of first virtual square S 1  and the middle point of first ridgeline  565 . It is possible to adjust the difference between the light distribution characteristics along the side of first virtual square S 1  and the light distribution characteristics along diagonal L 1  of first virtual square S 1  by adjusting the curvature radius of the arc. For example, when the curvature radius of the arc is large (when first ridgeline  565  is a substantially straight line), the region irradiated with light emitted from light flux controlling member  540  is square. On the other hand, when the curvature radius of the arc is small (when the center of diagonals L 1  of first virtual square S and the curvature center are close to each other), the region irradiated with the light emitted from light flux controlling member  540  has a rounded shape. 
         [0086]    In addition, first ridgeline  565  is disposed to protrude toward central axis CA side in plan view (see  FIG. 14A ). That is, the curvature center of the arc is located at a position on the straight line passing through center O 1  of first virtual square S 1  (the intersection of diagonals L 1 ) and the middle point of one side of first virtual square S 1 , and on the outer side of outermost first projected line  561 . Further, as described above, the curvature radius of the arc is set to a value greater than the distance between the intersection of diagonals L 1  of first virtual square S 1  and a middle point of one side of first virtual square S 1 . In the present embodiment, the curvature centers of first ridgelines  565  coincide with each other. In this manner, the degree of light condensing can be adjusted by determining whether to protrude the shape of the arc to central axis. 
         [0087]    In addition, as illustrated in  FIG. 14B , incidence region  641  of light flux controlling member  640  according to modification 2 of Embodiment 1 includes refraction section  150 , fresnel lens section  660  and outermost lens section  170 . Fresnel lens section  660  has a plurality of first projected lines  661  each including first incidence surface  662 , first reflecting surface  663 , first connection surface  664  and first ridgeline  665 . 
         [0088]    First incidence surface  662  is a curved surface. In a cross-section orthogonal to central axis CA (horizontal cross-section), the inner edge of first incidence surface  662  is a curve protruding outward. In addition, in a cross-section including central axis CA (vertical cross-section), first incidence surface  662  is tilted such that the distance from central axis CA increases toward the lower end of light flux controlling member  640  (reference surface). 
         [0089]    First reflecting surface  663  is also a curved surface. In a cross-section orthogonal to central axis CA (horizontal cross-section), the outer edge of first reflecting surface  663  is a curve protruding outward. 
         [0090]    In addition, first ridgeline  665  is disposed to protrude outward in plan view. That is, the curvature center of the arc is located at a position on a straight line passing through center O 1  of first virtual square S 1  (the intersection of diagonals L 1 ) and a middle point of one side of first virtual square S 1 , and the distance between the arc and the curvature center is greater than the distance between the center of first virtual square S 1  and the curvature center. 
         [0091]    (Effect) 
         [0092]    As described above, the light-emitting device including the light flux controlling member according to the present embodiment is provided with corner portions  172  at four corners of outermost lens section  170 , and thus can illuminate an illumination region with the light emitted via outermost lens section  170  in a square shape. That is, the use efficiency of light emitted from light emitting element  120  can be enhanced. In addition, since light-emitting device  100  can uniformly illuminate a square illumination region with light, quality can be enhanced. 
       Embodiment 2 
       [0093]    Light flux controlling member  740 , a light-emitting device and an illumination apparatus according to Embodiment 2 are respectively different from light flux controlling member  140 , light-emitting device  100  and illumination apparatus  400  according to Embodiment 1 in the shape of outermost lens section  770  of light flux controlling member  740 . Therefore, the same components as those of light flux controlling member  140 , light-emitting device  100  and illumination apparatus  400  according to Embodiment 1 are denoted with the same reference numerals, and the descriptions thereof are omitted. 
         [0094]    (Configuration of Light Flux Controlling Member) 
         [0095]      FIG. 15  is a perspective view of light flux controlling member  740  according to Embodiment 2 of the present invention. As illustrated in  FIG. 15 , incidence region  141  of light flux controlling member  740  according to Embodiment 2 includes refraction section  150 , fresnel lens section  160  and outermost lens section  770 . 
         [0096]    Outermost lens section  770  includes four second projected lines  771  and four corner portions  772 . Each of four second projected lines  771  is formed in a triangular prism shape. The cross-sectional shape of second projected line  771  taken along the plane orthogonal to the side on which the second projected line  771  is disposed is a triangular shape. Each second projected line  771  includes second incidence surface  773 , second reflecting surface  774  and second ridgeline  776 . In second projected line  771 , second incidence surface  773  is disposed on the inner side (central axis CA side), and second reflecting surface  774  is disposed on the outer side. 
         [0097]    Second incidence surface  773  and second reflecting surface  774  are each a planar surface. Second incidence surface  773  is tilted such that the distance from central axis CA increases toward the lower end (reference surface) of light flux controlling member  740 . The inner edge of second incidence surface  773  is a straight line in a cross-section orthogonal to central axis CA (horizontal cross-section), and also in a cross-section including central axis CA (perpendicular cross-section). Second reflecting surface  774  is tilted such that the distance to central axis CA decreases toward the lower end (reference surface) of light flux controlling member  740 . The outer edge of second reflecting surface  774  is a straight line in a cross-section orthogonal to central axis CA, and also in a cross-section including central axis CA. 
         [0098]    Each of four corner portions  772  is a part of a pyramid. Corner portion  772  includes third incidence surface  777 , third reflecting surface  778  and third ridgeline  779 . 
         [0099]    Third incidence surface  777  and third reflecting surface  778  are each composed of two planar surfaces. The two surfaces of third incidence surface  777  are each tilted such that the distance from central axis CA increases toward the lower end of light flux controlling member  740  (reference surface). In a cross-section orthogonal to central axis CA (horizontal cross-section), and also in a cross-section including central axis CA (perpendicular cross-section), the inner edges of two surfaces of third incidence surface  777  are each a straight line. The two surfaces of third reflecting surface  778  are each tilted such that the distance to central axis CA decreases toward the lower end of light flux controlling member  740  (reference surface). In a cross-section orthogonal to central axis CA, and also in a cross-section including central axis CA, the outer edges of the two surfaces of third reflecting surface  778  are each a straight line. 
         [0100]    Third ridgeline  779  is a boundary line between third incidence surface  777  and third reflecting surface  778 . This boundary may be chamfered to form a connection surface (third connection surface). In that case, third ridgeline  779  is a boundary line between third incidence surface  777  and the third connection surface. Third ridgeline  779  is a straight line whose distance to emission region  142  decreases toward second diagonal L 2  of second virtual square S 2  from the second projected line  771  side. Thus, a recessed portion is formed at a position where corner portion  772  and second diagonal L 2  of second virtual square S 2  intersect with each other. Of the light emitted from light emitting element  120  toward corner portion  772 , the light that passes through the recessed portion travels toward the region to be illuminated without being controlled by corner portion  772 . The amount of such uncontrolled light is small, and therefore a desired square-shaped illuminance distribution of illustrated in  FIG. 12  can be obtained as in Embodiment 1. Consequently, even when a burr-like wall part which is parallel to central axis CA is formed at the recessed portion from third ridgeline  779 , an effect similar to that of Embodiment 1 is obtained when the burr-like wall part has no light flux controlling function (a second modification of Embodiment 3, see  FIGS. 22 to 24 ). 
         [0101]    It is to be noted that, also in the present embodiment, first ridgeline  165  of first projected line  161  may be a curve protruding toward central axis CA side, or a curve protruding outward. 
         [0102]    (Effect) 
         [0103]    Light flux controlling member  740 , the light-emitting device and the illumination apparatus according to Embodiment 2 provide an effect similar to that of the light flux controlling member, the light-emitting device and the illumination apparatus according to Embodiment 1. 
       Embodiment 3 
       [0104]    Light flux controlling member  840 , a light-emitting device and an illumination apparatus according to Embodiment 3 are respectively different from light flux controlling member  140 , light-emitting device  100  and illumination apparatus  400  according to Embodiment 1 in the shape of outermost lens section  870  of light flux controlling member  840 . Therefore, the same components as those of light flux controlling member  140 , light-emitting device  100  and illumination apparatus  400  according to Embodiment 1 are denoted with the same reference numerals, and the descriptions thereof are omitted. 
         [0105]    (Configuration of Light Flux Controlling Member) 
         [0106]      FIG. 16  to  FIG. 18  illustrate a configuration of light flux controlling member  840  according to Embodiment 3.  FIG. 16  is a perspective view of light flux controlling member  840  according to Embodiment 3.  FIGS. 17A to 17C  are a plan view, a bottom view, and a side view of light flux controlling member  840 , respectively.  FIG. 18A  is a sectional view taken along line A-A of  FIG. 17B , and  FIG. 18B  is a sectional view taken along line B-B of  FIG. 17B . As illustrated in  FIG. 16  to  FIG. 18 , incidence region  841  of light flux controlling member  840  according to Embodiment 3 includes refraction section  150 , fresnel lens section  160  and outermost lens section  870 . 
         [0107]    Outermost lens section  870  includes four second projected lines  871  and four corner portions  872 . Each of four second projected lines  871  are formed in a substantially triangular prism shape. Second projected line  871  has a substantially triangular shape in a cross-section taken along the plane orthogonal to the side on which the second projected line  871  is disposed. Each second projected line  871  includes second incidence surface  873 , second reflecting surface  174  and second ridgeline  176 . In second projected line  871 , second incidence surface  873  is disposed on the inner side (central axis CA side), and second reflecting surface  174  is disposed on the outer side. 
         [0108]    Second incidence surface  873  includes tilted surface  873   a  disposed on the emission region  142  side, and parallel surface  873   b  disposed on the lower end side of light flux controlling member  840  (reference surface). Tilted surface  873   a  is tilted such that the distance from central axis CA increases toward the lower end (reference surface) of light flux controlling member  840 . On the other hand, parallel surface  873   b  is a surface parallel to central axis CA (optical axis LA of light emitting element  120 ). As described in Embodiment 1, incidence region  841  of light flux controlling member  840  according to Embodiment 3 is two-fold rotational symmetry or four-fold rotational symmetry around the center of first virtual square S 1  and second virtual square S 2  as the rotational axis. The rotational axis coincides with central axis CA of light flux controlling member  840  and optical axis LA of light emitting element  120 . Accordingly, parallel surface  873   b  is also parallel to the rotational axis. 
         [0109]    Each of four corner portions  872  is a part of a substantially conical member. Corner portion  872  includes third incidence surface  877 , third reflecting surface  178  and third ridgeline  179 . In corner portion  872 , third incidence surface  877  is disposed on the inner side (central axis CA side), and third reflecting surface  178  is disposed in the outer side. 
         [0110]    Each third incidence surface  877  is composed of two planar surfaces. The two surfaces of third incidence surface  877  are planar surfaces parallel to central axis CA (optical axis LA of light emitting element  120 ) and the above-described rotational axis. Third incidence surface  877  is continuous from parallel surface  873   b  of adjacent second incidence surface  873  and forms one planar surface. Consequently, the surface parallel to the above-described rotational axis (parallel surface  873   b ) included in the second incidence surface  873  and the surface parallel to the above-described rotational axis included in third incidence surface  877  are continuously disposed so as to enclose fresnel lens section  160 . 
         [0111]    (Effect) 
         [0112]    Light flux controlling member  840 , the light-emitting device and the illumination apparatus according to Embodiment 3 provide an effect similar to that of the light flux controlling member, the light-emitting device and the illumination apparatus according to Embodiment 1. In addition, in light flux controlling member  840  according to Embodiment 3, the planar surfaces parallel to central axis CA (optical axis LA of light emitting element  120  and the above-described rotational axis) are disposed to enclose fresnel lens section  160 . With this configuration, light flux controlling member  840  according to Embodiment 3 is suitable for manufacturing which uses a piece for shaping refraction section  150  and fresnel lens section  160 , and another piece for shaping outermost lens section  870 . 
         [0113]    (First Modification) 
         [0114]      FIG. 19  to  FIG. 21  illustrate a configuration of light flux controlling member  940  according to the first modification of Embodiment 3.  FIG. 19  is a perspective view of light flux controlling member  940  according to the first modification of Embodiment 3.  FIGS. 20A to 20C  are a plan view, a bottom view, and a side view of light flux controlling member  940 , respectively.  FIG. 21A  is a sectional view taken along line A-A of  FIG. 20B , and  FIG. 21B  is a sectional view taken along line B-B of  FIG. 20B . As illustrated in  FIG. 19  to  FIG. 21 , incidence region  941  of light flux controlling member  940  includes refraction section  150 , fresnel lens section  160  and outermost lens section  970 . 
         [0115]    Outermost lens section  970  includes four second projected lines  971 , and four corner portions  872 . Each of four second projected lines  971  is formed in a substantially triangular prism shape. Second projected line  971  has a substantially triangular shape in cross-section taken along the plane orthogonal to the side on which the second projected line  971  is disposed. Each second projected line  971  includes second incidence surface  973 , second reflecting surface  174  and second ridgeline  176 . In second projected line  971 , second incidence surface  973  is disposed on the inner side (central axis CA side), and second reflecting surface  174  is disposed on the outer side. Second incidence surface  973  is a planar surface parallel to central axis CA (optical axis LA of light emitting element  120 ) and the above-described rotational axis. 
         [0116]    Each of four corner portions  872  is a part of a substantially conical member. Corner portion  872  includes third incidence surface  877 , third reflecting surface  178  and third ridgeline  179 . In corner portion  872 , third incidence surface  877  is disposed on the inner side (central axis CA side), and third reflecting surface  178  is disposed on the outer side. 
         [0117]    Third incidence surface  877  is composed of two planar surfaces. The two surfaces of third incidence surface  877  are planar surfaces parallel to central axis CA (optical axis LA of light emitting element  120 ) and the above-described rotational axis. Third incidence surface  877  is continuous from adjacent second incidence surface  973  and forms one planar surface. As a result, the above-described surfaces (second incidence surface  973  and third incidence surface  877 ) parallel to the rotational axis are continuously disposed to enclose fresnel lens section  160 . 
         [0118]    (Effect) 
         [0119]    Light flux controlling member  940  according to the first modification of Embodiment 3 has an effect similar to that of light flux controlling member  840  according to Embodiment 3. 
         [0120]    (Second Modification) 
         [0121]      FIG. 22  to  FIG. 24  illustrate a configuration of light flux controlling member  1040  according to the second modification of Embodiment 3.  FIG. 22  is a perspective view of light flux controlling member  1040  according to the second modification of Embodiment 3.  FIGS. 23A to 23C  are a plan view, a bottom view, and a side view of light flux controlling member  1040 , respectively.  FIG. 24A  is a sectional view taken along line A-A of  FIG. 23B , and  FIG. 24B  is a sectional view taken along line B-B of  FIG. 23B . As illustrated in  FIG. 22  to  FIG. 24 , incidence region  1041  of light flux controlling member  1040  includes refraction section  150 , fresnel lens section  160  and outermost lens section  1070 . 
         [0122]    Outermost lens section  1070  includes four second projected lines  971 , and four corner portions  1072 . Each of four second projected lines  971  is formed in a substantially triangular prism shape. Second projected line  971  has a substantially triangular shape in cross-section taken along the plane orthogonal to the side on which the second projected line  971  is disposed. Each second projected line  971  includes second incidence surface  973 , second reflecting surface  174  and second ridgeline  176 . In second projected line  971 , second incidence surface  973  is disposed on the inner side (central axis CA side), and second reflecting surface  174  is disposed on the outer side. Second incidence surface  973  is a planar surface parallel to central axis CA (optical axis LA of light emitting element  120 ) and the above-described rotational axis. 
         [0123]    In four corner portions  1072 , burr-like wall part  1072   b  is provided to corner portion main bodies  1072   a  having the same configuration as corner portions  872  of light flux controlling member  940  according to the first modification. At the recessed portion of corner portion main body  1072   a , wall part  1072   b  is extended parallel to central axis CA and the above-described rotational axis from third ridgeline  779 . The internal surface (third incidence surface  877 ) of wall part main body  1072   a  and the internal surface of wall part  1072   b  are each composed of two planar surfaces. These planar surfaces are continuous from adjacent second incidence surface  973  and form one planar surface. As a result, the surfaces (second incidence surface  973 , third incidence surface  877  and the internal surface of wall part  1072   b ) parallel to the above-described rotational axis are continuously disposed to enclose fresnel lens section  160 . 
         [0124]    While wall part  1072   b  is provided between third incidence surface  877  and third reflecting surface  178 , wall part  1072   b  has no practical light flux controlling function in light flux controlling member  1040  according to the second modification. Therefore, in the second modification, the boundary line between wall part  1072   b  and third reflecting surface  178 , which has substantially the same track as that of third ridgeline  179  of light flux controlling member  940  according to the first modification, is considered to be third ridgeline  179 . 
         [0125]    (Effect) 
         [0126]    Light flux controlling member  1040  according to the second modification of Embodiment 3 has an effect similar to that of light flux controlling member  840  according to Embodiment 3. 
       Embodiment 4 
       [0127]    Light flux controlling member  1140 , a light-emitting device and an illumination apparatus according to Embodiment 4 are respectively different from light flux controlling member  540 , the light-emitting device and the illumination apparatus according to Embodiment 1 in the shape of outermost lens section  1170  of light flux controlling member  1140 . Therefore, the same components as those of light flux controlling member  540 , the light-emitting device and the illumination apparatus according to Embodiment 1 are denoted with the same reference numerals, and the descriptions thereof are omitted. 
         [0128]    (Configuration of Light Flux Controlling Member) 
         [0129]      FIG. 25  to  FIG. 27  illustrate a configuration of light flux controlling member  1140  according to Embodiment 4.  FIG. 25  is a perspective view of light flux controlling member  1140  according to Embodiment 4.  FIGS. 26A to 26C  are a plan view, a bottom view, and a side view of light flux controlling member  1140 , respectively.  FIG. 27A  is a sectional view taken along line A-A of  FIG. 26B , and  FIG. 27B  is a partially enlarged sectional view of the region indicated with the broken line in  FIG. 27A . 
         [0130]    As illustrated in  FIG. 25  to  FIG. 27 , light flux controlling member  1140  includes incidence region  1141  and emission region  142 . Incidence region  1141  includes refraction section  150 , fresnel lens section  560  and outermost lens section  1170 . Outermost lens section  1170  includes four second projected lines  1171 , and four corner portions  1172 . 
         [0131]    Each of four second projected lines  1171  is a part of a substantially conical member having a circular bottom surface whose vertex is located on the center O 2  side of second virtual square S 2 . Here the “substantially conical member having a circular bottom surface” means a stereoscopic shape which is formed by connecting the vertex and the outer peripheral edge of the circular bottom surface with a straight line or a curved line. Examples of the substantially conical member having a circular bottom surface include a cone whose line connecting the vertex and the circumferential points of the bottom surface is a straight line, a substantially conical member whose generatrix protrudes outward, a substantially conical member whose generatrix protrudes inward and the like. In the present embodiment, the substantially conical member (cone) is a substantially conical member whose generatrix protrudes outward. 
         [0132]    Each second projected line  1171  includes second incidence surface  1173 , second reflecting surface  1174 , second connection surface  1175  and second ridgeline  1176 . In second projected line  1171 , second incidence surface  1173  is disposed on the inner side (central axis CA side), and second reflecting surface  1174  is disposed on the outer side. 
         [0133]    Second incidence surface  1173  is a planar surface parallel to central axis CA (optical axis LA of light emitting element  120 ) and the center (rotational axis) of second virtual square S 2 . Second reflecting surface  1174  is a curved surface. In a cross-section orthogonal to central axis CA (horizontal cross-section), the outer edge of second reflecting surface  1174  is a curved line protruding outward. In addition, in a cross-section including central axis CA (perpendicular cross-section), the outer edge of second reflecting surface  1174  is a curved line protruding outward. Second reflecting surface  1174  corresponds to a part of a side surface of a substantially conical member, and connects two adjacent third reflecting surfaces  1178  so as to join adjacent two third reflecting surfaces  1178 . 
         [0134]    Second connection surface  1175  joins second incidence surface  1173  and second reflecting surface  1174 . Second connection surface  1175  may be a planar surface or a curved surface. In the present embodiment, second connection surface  1175  is a planar surface. In addition, it is also possible to directly join second incidence surface  1173  and second reflecting surface  1174  without forming second connection surface  1175 . 
         [0135]    Second ridgeline  1176  is a boundary line between second incidence surface  1173  and second connection surface  1175 . It is to be noted that, when second connection surface  1175  is not formed, second ridgeline  1176  is a boundary line between second incidence surface  1173  and second reflecting surface  1174 . When second connection surface  1175  is provided between second incidence surface  1173  and second reflecting surface  1174 , manufacturing performance can be enhanced by eliminating an acute angle portion. 
         [0136]    Each of four corner portions  1172  is a part of a substantially conical member having a circular bottom surface whose vertex is located on center O 2  side of second virtual square S 2 . Corner portion  1172  includes third incidence surface  1177 , third reflecting surface  1178  and third ridgeline  1179 . In the present embodiment, the substantially conical member (cone) is a substantially conical member whose generatrix protrudes outward. The shape of the substantially conical member in second projected line  1171 , and the shape of the substantially conical member in corner portion  1172  are identical to each other. 
         [0137]    Third incidence surface  1177  is composed of two planar surfaces parallel to central axis CA. Third reflecting surface  1178  is a curved surface. In a cross-section orthogonal to central axis CA (horizontal cross-section), the outer edge of third reflecting surface  1178  is a curved line protruding outward. In addition, in a cross-section including central axis CA (perpendicular cross-section), the outer edge of third reflecting surface  1178  is a curved line protruding outward. Third reflecting surface  1178  corresponds to a part of a side surface of a substantially conical member, and connects adjacent two second reflecting surface  1174  so as to join adjacent two second reflecting surface  1174 . As described above, the shape of the substantially conical member in second projected line  1171  and the shape of the substantially conical shape in corner portion  1172  are identical to each other, and therefore, in a cross-section orthogonal to central axis CA (horizontal cross-section), second reflecting surface  1174  and third reflecting surface  1178  have a circular shape. 
         [0138]    Third ridgeline  1179  is a boundary line between third incidence surface  1177  and third reflecting surface  1178 . Third ridgeline  1179  is a curve which is formed such that the distance to emission region  142  gradually decreases toward second diagonal L 2  of second virtual square S 2  from second projected line  1171  side. In addition, in plan view of incidence region  1141 , distance d 3  between the outermost edge of third reflecting surface  1178  and third ridgeline  1179  gradually decreases toward second diagonal L 2  of second virtual square S 2 . Thus, at a position where corner portion  1172  and second diagonal L 2  of second virtual square S 2  intersect with each other, a recessed portion is formed. It is to be noted that the boundary between third incidence surface  1177  and third reflecting surface  1178  may be chamfered to form a connection surface (third connection surface). In this case, third ridgeline  1179  is a boundary line between third incidence surface  1177  and the third connection surface. 
         [0139]    A metal mold for producing light flux controlling member  1140  according to Embodiment 4 is separated into a metal mold piece (piece) for manufacturing refraction section  150  and fresnel lens section  560 , and a metal mold piece for producing outermost lens section  1170 . In this case, the boundary between the outer edge of fresnel lens section  560  and the internal edge of outermost lens section  1170  is the boundary between the metal mold pieces. In view of this, light flux controlling member  1140  according to the present embodiment includes a predetermined fourth connection surface  1180  between fresnel lens section  560  and outermost lens section  1170  at incidence region  1141 . 
         [0140]    As illustrated in  FIG. 26B  and  FIG. 27B , fourth connection surface  1180  is disposed between fresnel lens section  560 , and second incidence surface  1173  and third incidence surface  1177 . Fourth connection surface  1180  is a planar surface. The width (the interval between the outer edge of fresnel lens section  560  and the internal edge of second projected line  1171 ) of fourth connection surface  1180  is not limited. The width of fourth connection surface  1180  is appropriately set in accordance with the size of light flux controlling member  1140 . Preferably, the width of fourth connection surface  1180  is 10 to 100 μm. 
         [0141]    (Effect) 
         [0142]    Light flux controlling member  1140 , the light-emitting device and the illumination apparatus according to Embodiment 4 provide an effect similar to that of the light flux controlling member, the light-emitting device and the illumination apparatus according to Embodiment 1. In addition, in light flux controlling member  1140  according to Embodiment 4, fourth connection surface  1180  is provided between fresnel lens section  560  and outermost lens section  1170 . With this configuration, light flux controlling member  1140  according to Embodiment 4 is suitable for manufacturing which uses a piece for shaping refraction section  150  and fresnel lens section  560 , and another piece for shaping outermost lens section  1170 . Further, in a cross-section orthogonal to central axis CA (horizontal cross-section), second reflecting surface  1174  and third reflecting surface  1178  have a circular shape, and thus a piece for producing second projected line  1171  and corner portion  1172  can be easily manufactured. 
         [0143]    This application is entitled to and claims the benefit of Japanese Patent Application No. 2013-178013 filed on Aug. 29, 2013, and Japanese Patent Application No. 2013-217232 filed on Oct. 18, 2013, the disclosure each of which including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY 
       [0144]    The light flux controlling member, the light-emitting device and the illumination apparatus according to the embodiments of the present invention can uniformly and efficiently illuminate a square illumination region. The light-emitting device according to the embodiments of the present invention is useful for a flash of a camera, for example. In addition, the illumination apparatus according to the embodiments of the present invention is useful for generally-used indoor illumination apparatuses, surface light source apparatuses in which a liquid crystal panel is an illuminated surface, and the like, for example. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           10  Fresnel lens 
           12  Groove 
           20  Cylindrical lens 
           100  Light-emitting device 
           120  Light emitting element 
           140 ,  140 ′,  540 ,  640 ,  740 ,  840 ,  940 ,  1040 ,  1140  Light flux controlling member 
           141 ,  541 ,  641 ,  841 ,  941 ,  1041 ,  1141  Incidence region 
           142  Emission region 
           143  Flange 
           150  Refraction section 
           160 ,  560 ,  660  Fresnel lens section 
           161 ,  561 ,  661  First projected line 
           162 ,  562 ,  662  First incidence surface 
           163 ,  563 ,  663  First reflecting surface 
           164 ,  564 ,  664  First connection surface 
           165 ,  565 ,  665  First ridgeline 
           170 ,  170 ′,  770 ,  870 ,  970 ,  1070 ,  1170  Outermost lens section 
           171 ,  771 ,  871 ,  971 ,  1171  Second projected line 
           172 ,  772 ,  872 ,  1072 ,  1172  Corner portion 
           173 ,  773 ,  873 ,  973 ,  1173  Second incidence surface 
           174 ,  774 ,  1174  Second reflecting surface 
           175 ,  1175  Second connection surface 
           176 ,  776 ,  1176  Second ridgeline 
           177 ,  777 ,  877 ,  1177  Third incidence surface 
           178 ,  778 ,  1178  Third reflecting surface 
           179 ,  779 ,  1179  Third ridgeline 
           400  Illumination apparatus 
           420  Cover 
           440  Substrate 
           873   a  Tilted surface 
           873   b  Parallel surface 
           1072   a  Corner portion main body 
           1072   b  Wall part 
           1180  Fourth connection surface 
         L 1  First diagonal 
         L 2  Second diagonal 
         S 1  First virtual square 
         S 2  Second virtual square 
         CA Central axis 
         LA Optical axis