Abstract:
A luminous flux control member ( 100 ) has: a light input region ( 110 ), to which light having been outputted from a light emitting element ( 210 ) is inputted; and a light output region ( 150 ), from which the light having been inputted from the light input region ( 110 ) is outputted. The input region ( 110 ) has: a refracting section ( 120 ); a reflection fresnel lens section ( 130 ), which is positioned outside of the refracting section ( 120 ); and a reflecting surface ( 140 ), which is positioned outside of the reflection fresnel lens section ( 130 ). The reflecting surface ( 140 ) reflects, toward the light output region ( 150 ), the light which has been inputted to the reflection fresnel lens section ( 130 ), and which has not been reflected (the light leaked from the reflection fresnel lens section ( 130 )).

Description:
TECHNICAL FIELD 
     The present invention relates to a light flux controlling member that controls a distribution of light emitted from a light emitting element, and a light emitting device including the light flux controlling member. 
     BACKGROUND ART 
     In recent years, in view of energy saving and environmental conservation, light emitting devices (LED flashes) using a light-emitting diode (hereinafter also referred to as “LED”) as a light source have been increasingly used for a light emitting device in an imaging 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 (see, for example, PTL 1). 
       FIG. 1A  is a sectional view of the light emitting device disclosed in PTL 1. As illustrated in  FIG. 1A , light emitting device  10  disclosed in PTL 1 includes substrate  20 , light source substrate  21 , light source  30  including a light emitting element and a phosphor, and Fresnel lens  40 . Fresnel lens  40  is disposed on substrate  20  in such a manner as to face the light emitting surface of light source  30 . 
       FIG. 1B  is a sectional view of Fresnel lens  40 . As illustrated in  FIG. 1B , refractive Fresnel lens section  41  and reflective Fresnel lens section  42  are formed on one side of Fresnel lens  40 . Refractive Fresnel lens section  41  is formed at a position which faces light source  30 . Reflective Fresnel lens section  42  is formed around refractive Fresnel lens section  41  in such a manner as to surround light source  30 . In Fresnel lens  40 , the surface on which refractive Fresnel lens section  41  and reflective Fresnel lens section  42  are formed functions as incidence region  43 , and the surface on the side opposite to incidence region  43  functions as emission region  44 . 
     In light emitting device  10  illustrated in  FIG. 1A , light emitted in a forward direction (upward direction in the drawing) from light source  30  is refracted in a predetermined direction at refractive Fresnel lens section  41 , and is then output from emission region  44 . On the other hand, light emitted in a lateral direction (horizontal direction in the drawing) from light source  30  is incident on incidence surface  45  of reflective Fresnel lens section  42 , and is reflected in a predetermined direction by reflecting surface  46 , and is then, output from emission region  44 . In this manner, light emitting device  10  disclosed in PTL 1 controls the distribution of the light emitted from light source  30  with use of Fresnel lens  40  including refractive Fresnel lens section  41  and reflective Fresnel lens section  42 . 
     CITATION LIST 
     Patent Literature 
     
         
         [PTL 1] Japanese Patent Application Laid-Open No. 2011-192494 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     Fresnel lens  40  disclosed in PTL 1 utilizes not only the light emitted in a forward direction from light source  30 , but also the light emitted in a lateral direction from light source  30 , and thus can brightly illuminate the irradiation target region. However, Fresnel lens  40  disclosed in PTL 1 has a problem that the leaked light from reflective Fresnel lens section  42  cannot be effectively utilized. 
     Generally, the form of reflective Fresnel lens section  42  is optimized such that the distribution of the light from the light emission center of light source  30  can be controlled to a desired distribution. However, light source  30  emits light by surface-emission, and therefore the light is emitted also from a peripheral portion of light source  30 . Consequently, after entering from incidence surface  45  of reflective Fresnel lens section  42 , part of light from a peripheral portion of light source  30  is not reflected by reflecting surface  46  and becomes leaked light, as illustrated in  FIG. 2 . As a result, as shown by the arrow in  FIG. 2 , part of the light from a peripheral portion of light source  30  becomes stray light  50 . Such stray light degrades the light use efficiency of Fresnel lens  40 . That is, Fresnel lens  40  disclosed in PTL 1 has a room for improvement in light use efficiency, by limiting the generation of stray light. 
     A conceivable method for limiting the generation of stray light derived from leaked light from a reflective Fresnel lens section in a light flux controlling member (lens) including the reflective Fresnel lens section is increasing the size of the light flux controlling member relative to the light source, or miniaturizing the form of the reflective Fresnel lens section. Both methods can limit the generation of stray light by limiting the generation of leaked light from the reflective Fresnel lens section. However, the former method cannot meet the demand of downsizing, and the latter method degrades the manufacturing performance. For this reason, it is not easy to improve the light use efficiency of a light flux controlling member by limiting the generation of leaked light. 
     Meanwhile, even when light is leaked from the reflective Fresnel lens section, the light use efficiency of the light flux controlling member may possibly be improved when the leaked light can be utilized. 
     An object of the present invention is to provide a light flux controlling member which include a reflective Fresnel lens section and can effectively utilize leaked light from the reflective Fresnel lens section. In addition, another object of the present invention is to provide a light emitting device including the light flux controlling member. 
     Solution to Problem 
     A light flux controlling member of an embodiment of the present invention controls a distribution of light emitted from a light emitting element, the light flux controlling member including: an incidence region on which light emitted from a light emitting element is incident; and an emission region from which light incident on the incidence region is emitted, wherein the incidence region includes a refraction section on which part of light emitted from the light emitting element is incident, the refraction section being configured to refract incident light toward the emission region, a reflective Fresnel lens section which is disposed outside the refraction section, and on which part of light emitted from the light emitting element is incident, the reflective Fresnel lens section being configured to reflect incident light toward the emission region, and a reflecting surface which is disposed outside the reflective Fresnel lens section, the reflecting surface being configured to reflect, toward the emission region, light which is incident on the reflective Fresnel lens section and is not reflected by the reflective Fresnel lens section, the reflective Fresnel lens section includes a plurality of concentric annular projections, each of the projections including a first inclined surface on which part of light emitted from the light emitting element is incident and a second inclined surface configured to reflect light incident on the first inclined surface toward the emission region, and an angle of the reflecting surface with respect to an optical axis of the light emitting element is smaller than an angle of the second inclined surface provided at an outermost position with respect to the optical axis of the light emitting element. 
     A light emitting device of an embodiment of the present invention includes: a light emitting element; and the light flux controlling member. 
     Advantageous Effects of Invention 
     The light flux controlling member of the embodiment of the present invention can effectively utilize also the leaked light from reflective Fresnel lens section with use of the reflecting surface, and thus is excellent in light use efficiency. In addition, in the light flux controlling member of the embodiment of the present invention, the leaked light from the reflective Fresnel lens section does not become stray light, and thus it is possible to limit the influence of the stray light on the other components. Therefore, the light emitting device including the light flux controlling member of the embodiment of the present invention has only a little influence on the other components, and is excellent in light use efficiency. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a sectional view of the light emitting device disclosed in PTL 1, and  FIG. 1B  is a sectional view of the Fresnel lens disclosed in PTL 1; 
         FIG. 2  illustrates a state where stray light is generated in the light emitting device disclosed in PTL 1; 
         FIG. 3A  is a plan view of the light flux controlling member of an embodiment,  FIG. 3B  is a side view of the light flux controlling member of the embodiment, and  FIG. 3C  is a bottom view of the light flux controlling member of the embodiment; 
         FIG. 4A  is a sectional view taken along line A-A of  FIG. 3A  and  FIG. 3C , and  FIG. 4B  is a partially enlarged sectional view of the region surrounded by the broken line in  FIG. 4A ; 
         FIG. 5  is a sectional view illustrating a configuration of a light emitting device of the embodiment; 
         FIG. 6A  is a sectional view of a light flux controlling member in which a reflecting surface and a second inclined surface are discontinuous with each other, and  FIG. 6B  is a partially enlarged sectional view of the region surrounded by the broken line in  FIG. 6A ; 
         FIG. 7A  is a plan view of a light flux controlling member of a comparative example,  FIG. 7B  is a side view of the light flux controlling member of the comparative example, and  FIG. 7C  is a bottom view of the light flux controlling member of the comparative example; 
         FIG. 8A  is a sectional view taken along line B-B of  FIG. 7A  and  FIG. 7C , and  FIG. 8B  is a partially enlarged sectional view of the region surrounded by the broken line in  FIG. 8A ; 
         FIG. 9  is a sectional view for describing the difference in form between the light flux controlling member of the embodiment and the light flux controlling member of the comparative example; 
         FIG. 10  illustrates light paths of a light emitting device of the comparative example; 
         FIG. 11  illustrates light paths of the light emitting device of the comparative example; 
         FIG. 12  illustrates light paths of the light emitting device of the embodiment; 
         FIG. 13  illustrates light paths of the light emitting device of the embodiment; 
         FIG. 14  is a graph illustrating results of a simulation of an illuminance distribution for the total light flux; and 
         FIG. 15  is a graph illustrating results of a simulation of an illuminance distribution for leaked light. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
     [Configuration of Light Flux Controlling Member and Light Emitting Device] 
       FIG. 3A  to  FIG. 4B  illustrate a configuration of light flux controlling member  100  according to an embodiment of the present invention.  FIG. 3A  is a plan view of light flux controlling member  100 ,  FIG. 3B  is a side view of light flux controlling member  100 , and  FIG. 3C  is a bottom view of light flux controlling member  100 .  FIG. 4A  is a sectional view taken along line A-A of  FIG. 3A  and  FIG. 3C , and  FIG. 4B  is a partially enlarged sectional view of the region surrounded by the broken line in  FIG. 4A .  FIG. 5  is a sectional view illustrating a configuration of light emitting device  200  according to the embodiment of the present invention. 
     As illustrated in  FIG. 5 , light flux controlling member  100  of the present embodiment is used in combination with light emitting element  210 . Light emitting element  210  is a light source of light emitting device  200 . Light emitting element  210  is, for example, a light-emitting diode (LED) such as a white light-emitting diode. As illustrated in  FIG. 5 , light flux controlling member  100  is disposed in such a manner that incidence region  110  (refraction section  120 ) of light flux controlling member  100  and the light emitting surface of light emitting element  210  face each other. 
     Light flux controlling member  100  controls the travelling direction of light emitted from light emitting element  210 . That is, light flux controlling member  100  controls the distribution of the light emitted from light emitting element  210 . Light flux controlling member  100  has a rotationally symmetrical form symmetrical about its central axis CA. Light flux controlling member  100  is disposed in such a manner that its central axis CA matches optical axis LA of light emitting element  210  (see  FIG. 5 ). 
     Light flux controlling member  100  is formed by injection molding. The material of light flux controlling member  100  is not particularly limited as long as light having a desired wavelength can pass therethrough. Examples of the material of light flux controlling member  100  include: light transmissive resins such as polymethylmethacrylate (PMMA), polycarbonate (PC), and epoxy resin (EP); or glass. 
     As illustrated in  FIG. 4A , light flux controlling member  100  includes incidence region  110  on which light emitted from light emitting element  210  is incident, and emission region  150  that is provided on the side opposite to incidence region  110  and is configured to output the light incident on incidence region  110 . Flange  160  may be provided between incidence region  110  and emission region  150 . 
     Incidence region  110  includes refraction section  120  provided at the center portion of incidence region  110 , reflective Fresnel lens section  130  provided outside refraction section  120 , and reflecting surface  140  provided outside reflective Fresnel lens section  130 . 
     Refraction section  120  is a planar surface formed at a position facing light emitting element  210  in such a manner as to intersect with central axis CA of light flux controlling member  100 . Refraction section  120  allows part of light emitted from light emitting element  210  (light emitted mainly in a forward direction) to enter light flux controlling member  100 , and refracts the incident light toward emission region  150  (see  FIG. 12 ). It is to be noted that the form of refraction section  120  may not necessarily be the planar surface, as long as the above-mentioned function can be achieved. For example, refraction section  120  may be a spherical surface, an aspherical surface, or a refractive Fresnel lens. In the present embodiment, refraction section  120  has a rotationally symmetrical form symmetrical about central axis CA of light flux controlling member  100  (see  FIG. 3C ). 
     Reflective Fresnel lens section  130  allows part of light emitted from light emitting element  210  (light emitted mainly in a lateral direction) to enter light flux controlling member  100 , and reflects the incident light toward emission region  150  (see  FIG. 12 ). Reflective Fresnel lens section  130  has a rotationally symmetrical form symmetrical about central axis CA of light flux controlling member  100 , and reflective Fresnel lens section  130  includes a plurality of annular projections  131  which are concentrically disposed (see  FIG. 3C ). As illustrated in  FIG. 3C  and  FIG. 4B , in this specification, projection  131  provided at the outermost position among annular projections  131  is referred to as first projection  131   a , and in the order from the outer side, annular projections  131  are respectively referred to as second projection  131   b  to seventh projection  131   g . To take in light emitted in a lateral direction from light emitting element  210 , first projection  131   a  has a size larger than that of projections  131   b  to  131   g.    
     Each projection  131  includes first inclined surface  132  serving as an incidence surface on which light emitted from light emitting element  210  is incident, and second inclined surface  133  serving as a reflecting surface which reflects light incident on first inclined surface  132  toward emission region  150 . In each projection  131 , first inclined surface  132  is provided on the inner side (on central axis CA side), and second inclined surface  133  is provided on the outer side. In addition, in each projection  131 , first inclined surface  132  and second inclined surface  133  may either be continuous or discontinuous with each other. In the former case, a ridgeline is formed between first inclined surface  132  and second inclined surface  133 . In the latter case, another surface is formed between first inclined surface  132  and second inclined surface  133 . In the example illustrated in  FIG. 4B , third inclined surface  134  is formed between first inclined surface  132  and second inclined surface  133 . When third inclined surface  134  is provided between first inclined surface  132  and second inclined surface  133  to eliminate an acute-angle portion (ridgeline portion), the manufacturing performance can be improved. It should be noted that the light flux control efficiency of projection  131  provided with third inclined surface  134  is lower than that of projection  131  provided with no third inclined surface  134 . The reason for this is that the amount of light which does not incident on projection  131  provided with third inclined surface  134  and becomes leaked light is increased. Reflecting surface  140  described later makes it possible to control the travelling direction of the leaked light, and can improve the light use efficiency. 
     The generatrix of first inclined surface  132  may either be a straight line or a curved line. The angle of first inclined surface  132  relative to optical axis LA of light emitting element  210  is not particularly limited as long as light incident on first inclined surface  132  can be refracted to second inclined surface  133  side, and is appropriately set in accordance with the size, position, or the like of light emitting element  210 . It is to be noted that, when the generatrix of first inclined surface  132  is a curved line, “the angle of first inclined surface  132 ” is the angle of the tangent to the generatrix of first inclined surface  132 . In view of the manufacturing performance, first inclined surface  132  is preferably inclined relative to optical axis LA of light emitting element  210  by about 3 to 5 degrees such that first inclined surface  132  on emission region  150  side is closer to the optical axis in comparison with incidence region  110  side. It is to be noted that the angle of first inclined surface  132  may either be the same or different among projections  131 . 
     The generatrix of second inclined surface  133  may either be a straight line or a curved line. The angle of second inclined surface  133  relative to optical axis LA of light emitting element  210  is not particularly limited as long as light incident on first inclined surface  132  can be reflected toward emission region  150  side, and may be appropriately set in accordance with the intended light distribution performance or the like. It is to be noted that, when the generatrix of second inclined surface  133  is a curved line, “the angle of second inclined surface  133 ” is the angle of the tangent to the generatrix of second inclined surface  133 . Normally, second inclined surface  133  is inclined relative to the optical axis by about 20 to 50 degrees such that second inclined surface  133  on incidence region  110  side is closer to the optical axis in comparison with emission region  150  side. The angle of second inclined surface  133  may either be the same or different among projections  131 . 
     Reflecting surface  140  is a surface extending from the outer edge of reflective Fresnel lens section  130  to the outer edge of emission region  150 . Flange  160  may be provided between the outer edge of reflecting surface  140  and the outer edge of the emission region  150 . Reflecting surface  140  reflects, toward emission region  150 , light which is incident on light flux controlling member  100  from first inclined surface  132  of reflective Fresnel lens section  130  and is not reflected by second inclined surface  133  of reflective Fresnel lens section  130  (in other words, leaked light from reflective Fresnel lens section  130 ) (see  FIG. 13 ). 
     Reflecting surface  140  is a rotationally symmetrical surface which is formed in such a manner as to surround central axis CA of light flux controlling member  100  (see  FIG. 3C ). The diameter of reflecting surface  140  gradually increases from incidence region  110  (light emitting element  210 ) side toward emission region  150  side. The generatrix of reflecting surface  140  may either be a straight line or a curved line. The angle of reflecting surface  140  relative to optical axis LA of light emitting element  210  (central axis CA of light flux controlling member  100 ) is greater than 0 and smaller than the angle of second inclined surface  133   a  provided at the outermost position, relative to optical axis LA of light emitting element  210 . Here, “the angle of reflecting surface  140 ” means the maximum value of the angle of the tangent to the generatrix of reflecting surface  140 . In addition, “the angle of second inclined surface  133   a  provided at the outermost position” means the minimum value of the angle of the tangent to the generatrix of second inclined surface  133   a.    
     The position of reflecting surface  140  is not particularly limited as long as leaked light from reflective Fresnel lens section  130  can be reflected toward emission region  150 . For example, reflecting surface  140  is formed on emission region  150  side, with respect to straight line L passing through light emission center  212  of light emitting element  210  and valley bottom  135  located between first projection  131   a  and second projection  131   b  (see  FIG. 9 ). With this configuration, only beams of light (leaked light) which are incident on first inclined surfaces  132   b  to  132   g  of small projections  131   b  to  131   g  (projections other than first projection  131   a ), and have not reached second inclined surfaces  133   b  to  133   g  reach reflecting surface  140  (light incident on first inclined surface  132   a  of first projection  131   a  does not reach). It is to be noted that reflecting surface  140  may be continuous with second inclined surface  133   a  of first projection  131   a  (see  FIG. 4A  and  FIG. 4B ), or discontinuous with second inclined surface  133   a  of first projection  131   a  (see  FIG. 6A  and  FIG. 6B ). 
     Emission region  150  is a planar surface which is formed on the side opposite to light emitting element  210  in such a manner as to face the irradiation target region. Emission region  150  is so formed as to intersect with central axis CA of light flux controlling member  100 . As illustrated in  FIG. 3A , emission region  150  is a rotationally symmetrical surface symmetrical about central axis CA of light flux controlling member  100 . Emission region  150  outputs the following light toward the irradiation target region: 1) the light which is incident on refraction section  120 ; 2) the light which is incident on first inclined surface  132  of reflective Fresnel lens section  130 , and is reflected by second inclined surface  133 ; and 3) the light which is incident on first inclined surface  132  of reflective Fresnel lens section  130 , and is reflected by reflecting surface  140 . 
     [Simulation of Light Path] 
     Light paths of light emitted from light emitting element  210  in light emitting device  200  including light flux controlling member  100  of the present embodiment illustrated in  FIG. 5  were simulated. In addition, for comparison, light paths of light emitted from light emitting element  210  also in light emitting device  200 ′ including light flux controlling member  100 ′ of the comparative example illustrated in  FIG. 7A  to  FIG. 8B  were simulated. 
       FIG. 7A  is a plan view of light flux controlling member  100 ′ of the comparative example,  FIG. 7B  is a side view of light flux controlling member  100 ′ of the comparative example, and  FIG. 7C  is a bottom view of light flux controlling member  100 ′ of the comparative example.  FIG. 8A  is a sectional view taken along line B-B of  FIG. 7A  and  FIG. 7C , and  FIG. 8B  is a partially enlarged sectional view of the region surrounded by the broken line in  FIG. 8A . As illustrated in  FIG. 7A  to  FIG. 8B , light flux controlling member  100 ′ of the comparative example is different from light flux controlling member  100  of the present embodiment in that reflecting surface  140  is not provided at an outer edge of reflective Fresnel lens section  130 . 
       FIG. 9  illustrates partially enlarged sectional views of light flux controlling members  100  and  100 ′ in an overlapped manner so as to show the difference in form between light flux controlling member  100  of the embodiment and light flux controlling member  100 ′ of the comparative example. As illustrated in  FIG. 9 , in light flux controlling member  100  of the embodiment, reflecting surface  140  is formed on emission region  150  side, with respect to straight line L passing through light emission center  212  of light emitting element  210  and valley bottom  135  located between first projection  131   a  and second projection  131   b . On the other hand, in light flux controlling member  100 ′ of the comparative example, flange outer peripheral surface  162  in parallel with optical axis LA is formed in place of reflecting surface  140 . It is to be noted that, as illustrated in  FIG. 9 , in this simulation, diaphragm  220  was disposed outside emission region  150 . 
       FIG. 10  and  FIG. 11  illustrate light paths of light emitting device  200 ′ of the comparative example.  FIG. 10  illustrates light paths of light emitted from the light emission center of light emitting element  210 , and  FIG. 11  illustrates light paths of light emitted from a peripheral portion of light emitting element  210 . 
     As illustrated in  FIG. 10 , light emitted in a forward direction from the light emission center of light emitting element  210  enters light flux controlling member  100 ′ from refraction section  120 , and is output from emission region  150 . In addition, light emitted in a lateral direction from the light emission center of light emitting element  210  enters light flux controlling member  100 ′ from first inclined surfaces  132   a  to  132   g  of projections  131   a  to  131   g  of light reflective Fresnel lens section  130 . The beams of light incident on first inclined surfaces  132   a  to  132   g  are respectively reflected by second inclined surfaces  133   a  to  133   g  of projections  131   a  to  131   g , and are output from emission region  150 . 
     On the other hand, as illustrated in  FIG. 11 , light emitted in a lateral direction from a peripheral portion of light emitting element  210  enters light flux controlling member  100 ′ from first inclined surfaces  132   a  to  132   g  of projections  131   a  to  131   g  of reflective Fresnel lens section  130 . Part of the light incident on first inclined surfaces  132   a  to  132   g  is reflected by second inclined surfaces  133   a  to  133   g  of respective projections, and is output from emission region  150 . However, the remaining part of the light incident on first inclined surfaces  132   a  to  132   g  cannot reach second inclined surfaces  133   a  to  133   g  of projections  131   a  to  131   g , and becomes leaked light. Such leaked light becomes stray light, and is output from flange outer peripheral surface  162 . Thus, leaked light from reflective Fresnel lens section  130  is not utilized for illumination of the irradiation target region. 
       FIG. 12  and  FIG. 13  illustrate light paths of light emitting device  200  of the embodiment.  FIG. 12  illustrates light paths of light emitted from the light emission center of light emitting element  210 , and  FIG. 13  illustrates light paths of light emitted from a peripheral portion of light emitting element  210 . 
     As illustrated in  FIG. 12 , light emitted in a forward direction from the light emission center of light emitting element  210  enters light flux controlling member  100  from refraction section  120 , and is output from emission region  150 . In addition, light emitted in a lateral direction from the light emission center of light emitting element  210  enters light flux controlling member  100  from first inclined surfaces  132   a  to  132   g  of projections  131   a  to  131   g  of reflective Fresnel lens section  130 . The beams of light incident on first inclined surfaces  132   a  to  132   g  are respectively reflected by second inclined surfaces  133   a  to  133   g  of projections  131   a  to  131   g , and are output from emission region  150 . 
     In addition, as illustrated in  FIG. 13 , also in light emitting device  200  of the embodiment, part of light emitted in a lateral direction from a peripheral portion of light emitting element  210  becomes leaked light from reflective Fresnel lens section  130 . However, in light emitting device  200  of the embodiment, such leaked light is reflected by reflecting surface  140 , and is output from emission region  150 . Thus, the leaked light is also utilized for illumination of the irradiation target region. 
     As can be seen from the light paths illustrated in the drawings, light emitting device  200  of the present embodiment can utilize leaked light from reflective Fresnel lens section  130  for illumination of the irradiation target region. 
     [Simulation of Illuminance] 
     The illuminance distributions on the illuminated surfaces in light emitting device  200  of the present embodiment and light emitting device  200 ′ of the comparative example were simulated. A planar surface which is disposed perpendicularly to optical axis LA of light emitting element  210  at a position separated by 1 m from light emitting element  210 , was used as the illuminated surface. It is to be noted that light flux controlling members  100  and  100 ′ each have a diameter of 10 mm. 
       FIG. 14  is a graph illustrating an illuminance distribution on the illuminated surface for the total light flux.  FIG. 15  is a graph illustrating an illuminance distribution on the illuminated surface for leaked light from reflective Fresnel lens section  130 . In the graphs, the abscissa represents the distance from the center of the illuminated surface (the point which intersects with the optical axis of light emitting element  210 ), and the ordinate represents the illuminance. The broken line represents simulation results of light emitting device  200 ′ of the comparative example, and the solid line represents simulation results of light emitting device  200  of the embodiment. 
     As can be seen from the graph of  FIG. 14 , light emitting device  200  of the present embodiment can illuminate the illuminated surface more brightly than light emitting device  200 ′ of the comparative example. In addition, as can be seen from the graph of  FIG. 15 , light emitting device  200  of the present embodiment distributes leaked light from reflective Fresnel lens section  130  to the peripheral portion of illuminated surface. 
     [Effect] 
     Light flux controlling member  100  of the present embodiment can utilize leaked light from reflective Fresnel lens section  130  for illumination of the irradiation target region, as well as the light refracted by refraction section  120  and the light reflected by reflective Fresnel lens section  130 . Therefore, light flux controlling member  100  of the present embodiment is excellent in light use efficiency. In addition, in light flux controlling member  100  of the present embodiment, leaked light from reflective Fresnel lens section  130  does not become stray light, and thus the influence of stray light on the other components can be limited. Therefore, light emitting device  200  including light flux controlling member  100  of the present embodiment has only a little influence on the other components, and is excellent in light use efficiency. 
     INDUSTRIAL APPLICABILITY 
     The light flux controlling member of the embodiment of the present invention is suitable for, for example, a lens of a light emitting device (flash) of an imaging camera and the like. 
     This application is entitled to and claims the benefit of Japanese Patent Application No. 2012-015270, filed on Jan. 27, 2012, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     REFERENCE SIGNS LIST 
     
         
           10  Light emitting device 
           20  Substrate 
           21  Light source substrate 
           30  Light source 
           40  Fresnel lens 
           41  Refractive Fresnel lens section 
           42  Reflective Fresnel lens section 
           43  Incidence region 
           44  Emission region 
           45  Incidence surface 
           46  Reflecting surface 
           100  Light flux controlling member 
           110  Incidence region 
           120  Refraction section 
           130  Reflective Fresnel lens section 
           131  Projection 
           132  First inclined surface 
           133  Second inclined surface 
           134  Third inclined surface 
           135  Valley bottom 
           140  Reflecting surface 
           150  Emission region 
           160  Flange 
           162  Flange outer peripheral surface 
           200  Light emitting device 
           210  Light emitting element 
           212  Light emission center 
           220  Diaphragm 
         CA Central axis of light flux controlling member 
         L Straight line passing through light emission center and valley bottom 
         LA Optical axis of light emitting element