JP2016045306A - Light flux control member, plane light source device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light flux control member that is used in plane light source devices suppressing luminance unevenness and high in light utilization efficiency.SOLUTION: A light flux control member has: a first incidence plane 151; a second incidence plane 152; a total reflection plane 153; and an emerging plane 154, and is arranged on a light emitting element to be arranged in an end part in a light emitting element array having a plurality of light emitting elements arranged in one row along a first direction. The emerging plane has: a first emerging region 154a; a second emerging region 154b; and a third emerging region 154c. Each emerging region is configured to have a following configuration in a cross section including an optical axis of the plurality of light emitting elements arranged on the light emitting element array. A first region is configured such that at least a part of light incident upon the second incidence plane and reflected upon the total reflection plane is emitted as refracting at least the part thereof on a center side in the light emitting element array further than a center axis CA1, a second region is configured to include a plane at which the light incident mainly upon the first incidence plane arrives, and a third region is configured to emit a light flux incident upon the second incidence plane and reflected upon the total reflection plane as diverging the light flux.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a light flux control member that controls the light distribution of light emitted from light emitting elements arranged at an end of a light emitting element array, and a surface light source device and a display device having the light flux control member.

  In recent years, a head-up display (hereinafter abbreviated as “HUD”) capable of directly displaying information such as a speed display on a screen (for example, a windshield of a car) has been used. In some HUDs, light emitted from a light emitting element is projected onto a screen via a liquid crystal panel or the like after light distribution is controlled by a lens (light flux controlling member). In this case, the user can recognize the information projected by the reflected light from the screen.

  In the HUD, a surface light source device using a plurality of light emitting elements (for example, LEDs) as a light source may be employed. However, when a plurality of light emitting elements are used, a region with high luminance and a region with low luminance are generated on the emission surface of the surface light source device, which may cause so-called luminance unevenness. Thus, several means for eliminating such luminance unevenness have been proposed (for example, Patent Document 1).

  1A is a cross-sectional view illustrating a configuration of a surface light source device 10 described in Patent Document 1, FIG. 1B is a plan view illustrating an outline of a lens array 14 described in Patent Document 1, and FIG. It is a graph which shows the luminance distribution (relative luminance) of the emitted light from the lens array 14 of literature 1, and FIG. 1D shows the emitted light from the lens array which does not have an uneven | corrugated shape in the boundary line of two adjacent lenses. It is a graph which shows luminance distribution (relative luminance).

  The surface light source device 10 described in Patent Document 1 includes a plurality of LEDs 12 arranged on a substrate 11, a lens array 14, and a diffusion plate 15. As shown in FIG. 1A, in the surface light source device 10, seven LEDs 12 are arranged in a line in the x direction. As shown in FIG. 1B, in the lens array 14, seven lenses 13 corresponding to the seven LEDs 12 are arranged in a line in the x direction. The surface light source device 10 focuses the emitted light from the LEDs 12 with the lens 13 and diffuses the focused light with the diffusion plate 15. In the lens array 14, a concave portion 17 and a convex portion 18 are formed on at least part of the boundary line 16 between two adjacent lenses 13. Due to the uneven shape, the luminance of the light emitted from the lens array 14 is averaged. As a result, compared to the case where the uneven shape is not formed (see FIG. 1D), the difference in luminance between the high luminance region and the low luminance region is small (see FIG. 1C). Therefore, in the surface light source device 10 described in Patent Document 1, even when a plurality of LEDs 12 (light emitting elements) are used, luminance unevenness can be reduced.

JP 2011-76832 A

  However, as shown in FIGS. 1C and 1D, the surface light source device 10 described in Patent Document 1 cannot be said to have sufficiently reduced luminance unevenness. Further, the surface light source device 10 described in Patent Document 1 diffuses the light focused by the lens 13 by the diffusion plate 15. For this reason, when using the surface light source device 10 of patent document 1 as a light source of HUD, the emitted light from the surface light source device 10 may be irradiated also to areas other than a liquid crystal panel, and light utilization efficiency may fall. There is.

  The present invention has been made in view of the above points, and is a surface light source device having at least one light emitting element array in which a plurality of light emitting elements are arranged in a line, and has low luminance unevenness and light use efficiency. An object of the present invention is to provide a surface light source device having a high height. Another object of the present invention is to provide a display device having the surface light source device and a light flux controlling member used in the surface light source device.

  The light flux controlling member according to the present invention is arranged at an end of the light emitting element row in the surface light source device having at least one light emitting element row in which a plurality of light emitting elements are arranged in a row along the first direction. A light flux controlling member disposed on the light emitting element so that a central axis (first central axis) thereof is perpendicular to the first direction and coincides with an optical axis of the light emitting element. A bottom surface of a rotationally symmetric recess having an axis as a rotation axis; a first incident surface on which at least a part of light emitted from the light emitting element is incident; a second incident surface configuring a side surface of the recess; A rotationally symmetric curved surface disposed so as to surround the recess and having the central axis as a rotation axis, the total reflection surface (first total reflection surface) reflecting light incident on the second incident surface; and the center Arranged at a position intersecting the axis and entering at the first entrance surface. The total reflection in a direction perpendicular to the central axis, and an emission surface (first emission surface) that emits the light incident on the second incident surface and the light reflected by the total reflection surface. The spacing between the surfaces increases from the concave portion side toward the emission surface side, and the emission surface is located at a position intersecting the first emission region disposed on the end side in the light emitting element array and the central axis. A cross section including the second emission region arranged and the third emission region arranged on the center side of the light emitting element row, and including the optical axes of the plurality of light emitting elements arranged on the light emitting element row. The first emission region includes a surface on which light incident on the second incident surface and reflected by the total reflection surface reaches, is incident on the second incident surface, and is reflected on the total reflection surface At least part of the emitted light is emitted from the central axis. The second output region includes a surface on which light incident on the first incident surface reaches, and the third output region is incident on the second incident surface. In addition, a configuration is adopted in which a light beam incident on the second incident surface and reflected by the total reflection surface is emitted while being diverged, including a surface on which the light reflected by the total reflection surface reaches.

  The surface light source device according to the present invention includes a light emitting element array in which a plurality of light emitting elements are arranged in a line along a first direction, and the light emitting element arranged at an end in the light emitting element array, A first light flux control member disposed such that a central axis (first central axis) is orthogonal to the first direction and coincides with an optical axis of the light emitting element, and the first light flux control The member is a light flux controlling member according to the present invention, and adopts a configuration in which the first emission region is disposed so as to be located on an end side in the light emitting element array.

  The display device according to the present invention employs a configuration including the surface light source device according to the present invention and an irradiated member that is irradiated with light emitted from the surface light source device.

  The surface light source device according to the present invention can suppress luminance unevenness and can use light emitted from the light emitting element with high efficiency. Therefore, the display device according to the present invention can suppress display unevenness and efficiently use light emitted from a plurality of light emitting elements.

1A and 1B are diagrams for explaining the configuration of the surface light source device described in Patent Document 1, and FIGS. 1C and 1D are graphs for explaining the luminance distribution of light emitted from the lens array. FIG. 2 is a cross-sectional view of the display device according to the embodiment. 3A to 3E are views for explaining the configuration of the first light flux controlling member. 4A to 4E are views for explaining the configuration of the second light flux controlling member. 5A and 5B are graphs showing the relationship between the first emission angle θ1 and the second emission angle θ2 for the light emitted from the first light flux control member or the second light flux control member. FIG. 6 is a diagram illustrating an optical path of light in the surface light source device according to the embodiment until reaching the irradiated member. FIG. 7A is a graph showing the relationship between the emission angle of the emitted light from the light emitting element and the relative luminous intensity, and FIG. 7B is a graph showing the relationship between the emission angle of the emitted light from the first light flux controlling member and the relative luminous intensity. It is. FIG. 8A is a graph showing the relationship between the emission angle of the emitted light from the second light flux control member and the relative luminous intensity, and FIG. 8B shows the output from the two first light flux control members and one second light flux control member. It is a graph which shows the relationship between the outgoing angle of incident light, and relative luminous intensity. FIG. 9 is a graph showing the illuminance distribution of light reaching the irradiated member in the display device according to the embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, a display device that can be used to display information on a screen in a HUD will be described. The HUD has a display device, a projection lens for appropriately projecting light from the display device onto the screen, and a screen. Light emitted from the display device is irradiated onto the screen through a projection optical system including a projection lens.

(Configuration of surface light source device and display device)
FIG. 2 is a cross-sectional view of display device 100 according to the embodiment of the present invention. As shown in FIG. 2, the display device 100 includes a surface light source device 110 and an irradiated member 120. Here, as shown in FIG. 2, the direction in which the three light emitting elements 140 are arranged is defined as an x direction (first direction). Also, a direction perpendicular to the x direction and parallel to the surface of the substrate 130 (a depth direction in the drawing of FIG. 2) is defined as a y direction (second direction).

  The surface light source device 110 is a light source of the display device 100. The surface light source device 110 includes a substrate 130, a plurality of light emitting elements 140, two first light flux control members 150, and one or more second light flux control members 160.

  The substrate 130 supports the light emitting element 140, the first light flux control member 150, and the second light flux control member 160. The type of the substrate 130 is not particularly limited. As the substrate 130, a circuit substrate is preferably used from the viewpoint of supplying electricity to the light emitting element 140. For example, the substrate 130 is a glass composite substrate, a glass epoxy substrate, an Al substrate, or the like.

  The plurality of light emitting elements 140 are light sources of the surface light source device 110 and are fixed on the substrate 130. The plurality of light emitting elements 140 are arranged in a line along the x direction. In the following description, the plurality of light emitting elements 140 arranged in a row are also referred to as “light emitting element rows”. The number of the light emitting elements 140 can be appropriately changed according to the size of the irradiated member 120, the distance between the substrate 130 and the irradiated member 120, and the like. In the present embodiment, the number of light emitting elements 140 is three. Further, the interval between the two light emitting elements 140 is not particularly limited. The interval between the two light emitting elements 140 can be appropriately changed according to the luminance of the light emitting element 140, the light distribution characteristics of the first light flux controlling member 150 and the second light flux controlling member 160, and the like. Here, “the optical axis LA of the light emitting element 140” refers to the traveling direction of light at the center of the total luminous flux emitted three-dimensionally from one light emitting element 140. The kind of the light emitting element 140 is not particularly limited. Examples of the light emitting element 140 include a light emitting diode (LED) and a halogen lamp.

  The first light flux control member 150 and the second light flux control member 160 respectively control the light distribution of the emitted light from the light emitting element 140. The first light flux controlling member 150 has a first central axis CA1 that is the central axis thereof orthogonal to the x direction on the light emitting element 140 disposed at the end of the light emitting element array, and the optical axis of the light emitting element 140. It arrange | positions so that it may correspond with LA. Further, the second light flux controlling member 160 has a second central axis CA2 that is the central axis on the light emitting element 140 disposed at a position other than the end (center) in the light emitting element row, and is orthogonal to the x direction. It arrange | positions so that it may correspond with the optical axis LA of the light emitting element 140. FIG. Here, the “first central axis CA1” refers to a rotationally symmetric axis of a first incident surface 151, a second incident surface 152, and a first total reflection surface 153 of a first light flux controlling member 150 described later. Further, the “second central axis CA2” refers to a rotationally symmetric axis of a third incident surface 161, a fourth incident surface 162, and a second total reflection surface 163 of a second light flux controlling member 160 described later. Details of the first light flux control member 150 and the second light flux control member 160 will be described later. The first central axis CA1 and the second central axis CA2 are also orthogonal to the y direction.

  The irradiated member 120 is irradiated with light emitted from the surface light source device 110. The irradiated member 120 is, for example, a liquid crystal panel or a combination of a liquid crystal panel and a diffusion plate. Examples of the diffusing plate include a transparent plate-like member that has been subjected to light diffusion treatment (for example, roughening treatment) and a transparent plate-like member that is mixed with scatterers such as beads. Alternatively, the light diffusion treatment may be performed directly on the transparent substrate of the liquid crystal panel.

(Configuration of first light flux controlling member)
Next, the configuration of the first light flux control member 150 and the second light flux control member 160 according to the present embodiment will be described. First, the configuration of the first light flux controlling member 150 disposed on the light emitting element 140 disposed at the end in the light emitting element array will be described.

  FIG. 3 is a view for explaining the configuration of the first light flux controlling member 150. 3A is a plan view of the first light flux controlling member 150, FIG. 3B is a front view, FIG. 3C is a bottom view, and FIG. 3D is a cross-sectional view taken along the line DD shown in FIG. 3A. FIG. 3E is a sectional view taken along line EE shown in FIG. 3A.

  The first light flux controlling member 150 controls the light distribution of the emitted light from the light emitting element 140 disposed at the end in the light emitting element array. The first light flux controlling member 150 has a first incident surface 151, a second incident surface 152, a first total reflection surface 153, and a first emission surface 154. The first light flux controlling member 150 may be provided with a first flange 155a, a second flange 155b, and a second flange 155c. The first flange 155a is provided outside the first emission region 154a (described later), the second flange 155b is provided outside the second emission region 154b (described later), and the third flange 155c is the third emission region. It is provided outside 154c (described later). On the back side of these flanges, a first support portion 156 for fixing the first light flux controlling member 150 to the substrate 130 may be provided. The method for fixing the first light flux controlling member 150 to the substrate 130 is not particularly limited. For example, the first light flux controlling member 150 and the substrate 130 can be fixed to each other by bonding the first support portion 156 to the substrate 130 with an adhesive.

  The planar view shape of the first light flux controlling member 150 is not particularly limited. In the present embodiment, the planar view shape of the first light flux controlling member 150 is a rectangle having the x direction as the short direction and the y direction as the long direction. The length in the x direction of the first light flux controlling member 150 according to the present embodiment is about 12 mm, and the length in the y direction is about 16 mm.

  The first incident surface 151 makes light emitted from the light emitting element 140 emitted at a relatively small angle with respect to the optical axis LA, and refracts the incident light toward the first emission surface 154. The first incident surface 151 forms a bottom surface of a rotationally symmetric first recess having the first central axis CA1 as a rotation axis, and is formed to intersect the first central axis CA1. The shape of the 1st entrance plane 151 will not be specifically limited if said function can be exhibited. In addition, the surface of the first incident surface 151 may be a spherical surface or an aspherical surface. In the present embodiment, the first incident surface 151 has a positive power with respect to at least a part of the light emitted from the light emitting element 140. That is, the shape of the first incident surface 151 is a convex lens shape, and the surface of the first incident surface 151 is an aspherical surface.

  The second incident surface 152 makes light emitted from the light emitting element 140 emitted at a relatively large angle with respect to the optical axis LA and refracts the incident light toward the first total reflection surface 153. It is a curved surface. The second incident surface 152 constitutes the side surface of the first recess. From the viewpoint of forming the first light flux controlling member 150, the second incident surface 152 is preferably slightly inclined with respect to the first central axis CA1. In this case, the second incident surface 152 is inclined so as to move away from the first central axis CA1 as it approaches a surface (first reference surface) including the lower end of the first light flux controlling member 150 (lower end of the first support portion 156). doing. The inclination angle of the second incident surface 152 is preferably greater than 0 ° and within a range of 10 ° or less with respect to the first central axis CA1 in any cross section including the first central axis CA1. More preferably, it is not more than 0 °. In the present embodiment, the inclination angle of the second incident surface 152 is 5 °.

  The first total reflection surface 153 reflects the light incident on the second incident surface 152 toward the first emission surface 154. The first total reflection surface 153 is a rotationally symmetric curved surface that is disposed so as to surround the first recess and has the first central axis CA1 as a rotation axis. The first total reflection surface 153 may be a conical surface, a spherical surface, or an aspherical surface. In the present embodiment, the first total reflection surface 153 is an aspherical surface. Moreover, it is preferable that the 1st total reflection surface 153 inclines with respect to 1st central axis CA1 from a viewpoint of totally reflecting the arrived light. The interval between the first total reflection surfaces 153 in the direction orthogonal to the first central axis CA1, that is, the outer diameter of the first total reflection surface 153 increases from the first recess side toward the first emission surface 154 side.

  The first emission surface 154 is disposed at a position that intersects the first central axis CA1. The first exit surface 154 emits the light incident on the first entrance surface 151 and the light incident on the second entrance surface 152 and reflected by the first total reflection surface 153. The first emission surface 154 is a curved surface having a curvature in the x direction. The first emission surface 154 may or may not have a curvature in a cross section perpendicular to the y direction, that is, the x direction, and parallel to the first central axis CA1. In the present embodiment, the first exit surface 154 has no curvature in the y direction.

  In the surface light source device 110, the first emission surface 154 includes a first emission region 154a arranged on the end side in the light emitting element array, and a second emission region 154b arranged at a position intersecting with the first central axis CA1. And a third emission region 154c disposed on the center side in the light emitting element array (see FIGS. 2 and 3D).

  The first emission region 154a is a surface on the end side of the light-emitting element array of the first light flux controlling member 150, on which the light incident on the second incident surface 152 and reflected by the first total reflection surface 153 arrives. Including. The first emission region 154a has at least a part of the light incident on the second incident surface 152 and reflected by the first total reflection surface 153 on the center side (second light flux) in the light emitting element array with respect to the first central axis CA1. The light is emitted while being refracted toward the control member 160 side.

  The second emission region 154b mainly includes a surface on which light incident on the first incident surface 151 reaches. The region on the first emission region 154a side (the end portion side in the light emitting element array) of the second emission region 154b with the virtual plane parallel to the y direction including the first central axis CA1 as a boundary is the second emission region 154b. Compared with the region on the third emission region 154c side (the center side in the light emitting element array), the light that has reached (the light incident on the first incident surface 151) is refracted toward the first central axis CA1. Is formed. That is, the positive power of the region on the first emission region 154a side of the second emission region 154b is stronger than the region on the third emission region 154c side of the second emission region 154b. This generally corresponds to the end side of the light emitting element array with respect to the irradiated surface (irradiated member 120) facing the light emitting elements 140 arranged on the light emitting element array, rather than the first light flux controlling member 150. The area is narrower than the area corresponding to the distance between the first light flux controlling member 150 and the second light flux controlling member 160, and the light emitted from the first light emitting area 154a side of the second light emitting area 154b needs to be greatly expanded. By not. The shape of the area on the third emission area 154c side of the second emission area 154b can be appropriately designed according to the interval between the first light flux control member 150 and the adjacent second light flux control member 160. The region on the third emission region 154c side of the second emission region 154b may have positive power or negative power. For example, when the distance between the first light flux controlling member 150 and the adjacent second light flux controlling member 160 is short, the shape of the second light emitting area 154b on the third light emitting area 154c side is a convex lens shape having positive power. is there. On the other hand, when the distance between the first light flux controlling member 150 and the adjacent second light flux controlling member 160 is long, the shape of the second light emitting region 154b on the third light emitting region 154c side is a concave lens shape having negative power. is there. The second emission region 154b preferably includes a surface from which the light emitted from the light emitting element 140 is emitted with an emission angle of 5 ° or more and 20 ° or less and incident on the first incident surface 151. In the present embodiment, the second emission region 154b includes light emitted from the light emitting element 140 at an emission angle of 5 to 20 ° and incident on the first incident surface 151, and at least part of the light. Has positive power. That is, in the x direction and a cross section parallel to the optical axis LA of the light emitting element 140, the second emission region 154b includes a region having a substantially convex lens shape. In addition, in the second emission region 154b, light emitted from the light emitting element 140 at an emission angle other than 5 to 20 ° and incident on the first incident surface 151, and the second incident surface 152 (of the second incident surface 152). Of these, the light incident on the both ends of the y direction and reflected by the first total reflection surface 153 (the region of the first total reflection surface 153 located at both ends in the y direction) also reaches. The second emission region 154b also emits these lights.

  The third emission region 154c includes a surface that is incident on the second incident surface 152 and reaches the light reflected by the first total reflection surface 153 in the central portion of the light-emitting element array of the first light flux controlling member 150. . The third emission region 154c emits the light beam incident on the second incident surface 152 and reflected by the first total reflection surface 153 while diverging. That is, in the cross section parallel to the x direction and the optical axis LA of the light emitting element 140, the third emission region 154c includes a region having a substantially concave lens shape, is incident on the second incident surface 152, and is the first total reflection surface 153. And has a negative power with respect to at least a part of the light reflected by.

  The material of the first light flux controlling member 150 is not particularly limited as long as it can pass light having a desired wavelength. The material of the first light flux controlling member 150 is, for example, a light transmissive resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), and epoxy resin (EP), or glass. The first light flux controlling member 150 can be manufactured, for example, by injection molding.

(Configuration of second light flux controlling member)
Next, the configuration of the second light flux controlling member 160 disposed on the light emitting element 140 disposed on the light emitting element array other than the end (center) will be described.

  FIG. 4 is a diagram for explaining the configuration of the second light flux controlling member 160. 4A is a plan view of the second light flux controlling member 160, FIG. 4B is a front view, FIG. 4C is a bottom view, and FIG. 4D is a cross-sectional view taken along line DD shown in FIG. 4A. 4E is a cross-sectional view taken along line EE shown in FIG. 4A.

  The second light flux controlling member 160 controls the light distribution of the emitted light from the light emitting elements 140 arranged in the light emitting element row other than the end (center) among the three light emitting elements 140. The second light flux controlling member 160 is disposed between the two first light flux controlling members 150 in the x direction (light emitting element array). The second light flux controlling member 160 has a third incident surface 161, a fourth incident surface 162, a second total reflection surface 163, and a second exit surface 164. The second light flux controlling member 160 may be provided with a fourth flange 165a and a fifth flange 165b. The fourth flange 165a is provided outside the fourth emission region 164a (described later), and the fifth flange 165b is provided outside the fifth emission region 164b (described later). On the back side of these flanges, a second support portion 166 for fixing the second light flux controlling member 160 to the substrate 130 may be provided. The method for fixing the second light flux controlling member 160 to the substrate 130 is not particularly limited. For example, the second light flux controlling member 160 and the substrate 130 can be fixed to each other by bonding the second support portion 166 to the substrate 130 with an adhesive.

  The planar view shape of the second light flux controlling member 160 is not particularly limited. In the present embodiment, the planar view shape of the second light flux controlling member 120 is a rectangle having the x direction as the short direction and the y direction as the long direction. The length in the x direction of the second light flux controlling member 160 according to the present embodiment is about 12 mm, and the length in the y direction is about 16 mm. The material of the second light flux controlling member 160 is not particularly limited as long as it can transmit light having a desired wavelength, and is the same as the material of the first light flux controlling member 150, for example.

  The third incident surface 161 makes light emitted from the light emitting element 140 emitted at a relatively small angle with respect to the optical axis LA and refracts the incident light toward the second emission surface 164. The third incident surface 161 forms a bottom surface of a rotationally symmetric second recess having the second central axis CA2 as a rotation axis, and is formed so as to intersect with the second central axis CA2. The third incident surface 161 has a positive power with respect to at least a part of the light emitted from the light emitting element 140. The shape of the 3rd entrance plane 161 will not be specifically limited if said function can be exhibited. The third incident surface 161 may be a spherical surface or an aspherical surface. In the present embodiment, the third incident surface 161 has a substantially conical shape, and the third incident surface 161 is an aspherical surface.

  The fourth incident surface 162 makes light emitted from the light emitting element 140 emitted at a relatively large angle with respect to the optical axis LA and refracts the incident light toward the third total reflection surface 163. It is a curved surface. The fourth entrance surface 162 constitutes a side surface of a second rotationally symmetric recess having the second central axis CA2 as a rotation axis. From the viewpoint of forming the second light flux controlling member 160, the fourth incident surface 162 is preferably slightly inclined with respect to the second central axis CA2. In this case, the fourth incident surface 162 is inclined away from the second central axis CA2 as it approaches a surface (second reference surface) including the lower end of the second light flux controlling member 160 (lower end of the second support portion 166). doing. The inclination angle of the fourth incident surface 162 is preferably greater than 0 ° and within a range of 10 ° or less with respect to the second central axis CA2 in any cross section including the second central axis CA2. More preferably, it is not more than 0 °. In the present embodiment, the inclination angle of the fourth incident surface 162 is 5 °.

  The second total reflection surface 163 reflects the light incident on the fourth incident surface 162 toward the second emission surface 164. The second total reflection surface 163 is a rotationally symmetric curved surface that is disposed so as to surround the second recess and has the second central axis CA2 as a rotation axis. The second total reflection surface 163 may be a conical surface, a spherical surface, or an aspherical surface. In the present embodiment, second total reflection surface 163 is an aspherical surface. The second total reflection surface 163 is preferably inclined with respect to the second central axis CA2 from the viewpoint of total reflection of the reached light. The distance between the second total reflection surfaces 163 in the direction orthogonal to the second central axis CA2, that is, the outer diameter of the second total reflection surface 163 increases from the second recess side toward the second emission surface 164 side.

  The second emission surface 164 is disposed at a position that intersects the second central axis CA2. The second exit surface 164 emits the light incident on the third entrance surface 161 and the light incident on the fourth entrance surface 162 and reflected by the second total reflection surface 163. The second emission surface 164 is a curved surface having a curvature in the x direction. The second emission surface 164 may or may not have a curvature in a cross section orthogonal to the y direction, that is, the x direction and parallel to the second central axis CA2. Further, the curvature in the y direction of the second light exit surface 164 of the second light flux control member 160 may be different from the curvature in the y direction of the first light exit surface 154 of the first light flux control member 150, but is the same. Is preferred. By making these curvatures the same, the light distribution width in the y direction of the first light flux controlling member 150 and the light distribution width in the y direction of the second light flux controlling member 160 can be made substantially the same. In the present embodiment, the curvature of the second exit surface 164 in the y direction is the same as the curvature of the first exit surface 154 in the y direction, and has no curvature in the y direction.

  In the surface light source device 110, the second emission surface 164 includes a fourth emission region 164a disposed at a position intersecting the second central axis CA2, and two second emission surfaces 164a disposed so as to sandwich the fourth emission region 164a in the x direction. 5 emission regions 164b (see FIGS. 2 and 4D).

  The fourth emission region 164a mainly includes a surface on which light incident on the third incident surface 161 reaches. The shape of the fourth emission region 164a can be appropriately designed according to the distance from the adjacent light flux control member (the first light flux control member 150 or the second light flux control member 160). For example, when the interval between adjacent light flux controlling members is long, the shape of the fourth emission region 164a is formed in a concave lens shape. In the present embodiment, the fourth emission region 164a has a positive power with respect to at least a part of the light emitted from the light emitting element 140 at an emission angle of 5 to 20 ° and incident on the third incident surface 161. . That is, the fourth emission region 164a includes a region having a substantially convex lens shape. In addition, in the present embodiment, light emitted from the light emitting element 140 at an emission angle other than 5 to 20 ° and incident on the third incident surface 161 and the fourth incident surface 162 ( The light that is incident on the fourth incident surface 162 at a region located at both ends in the y direction and reflected by the second total reflection surface 163 (the region that is located at both ends in the y direction of the second total reflection surface 163) To reach. The fourth emission region 164a also emits these lights.

  The fifth emission region 164b is a surface on the end side of the light emitting element array of the second light flux controlling member 160, on which the light incident on the fourth incident surface 162 and reflected by the second total reflection surface 163 arrives. Including. The fifth emission region 164c emits the light beam incident on the fourth incident surface 162 and reflected by the second total reflection surface 163 while diverging. That is, the fifth emission region 164b includes a region having a substantially concave lens shape, and the fifth emission region 164b is incident on at least a part of the light incident on the fourth incident surface 162 and reflected by the second total reflection surface 163. On the other hand, it has negative power.

(Light distribution characteristics of luminous flux control member)
Next, the light distribution characteristics of the first light flux control member 150 and the second light flux control member 160 will be described.

  FIG. 5 shows the emission angle of the light emitted from the light emitting element 140 (hereinafter also referred to as “first emission angle θ1”) and the light output from the light flux control member (the first light flux control member 150 or the second light flux control member 160). It is a graph which shows the relationship (simulation result) with the outgoing angle of incident light (henceforth "2nd outgoing angle (theta) 2"). 5A and 5B, the horizontal axis represents the first emission angle θ1 (°), and the vertical axis represents the second emission angle θ2 (°). 5A includes a first emission angle in a virtual plane that includes the optical axis LA of the light emitting element 140 and the central axis (first central axis CA1 or second central axis CA2) of the light flux controlling member and extends along the x direction. The relationship between (theta) 1 and 2nd output angle (theta) 2 is shown. FIG. 5B includes a first emission angle θ1 in a virtual plane including the optical axis LA of the light emitting element 140 and the central axis (first central axis CA1 or second central axis CA2) of the light flux controlling member and extending along the y direction. The relationship with 2nd output angle (theta) 2 is shown.

  In FIG. 5A, from the light emission center of the light emitting element 140 disposed under the first light flux controlling member 150 to the center side (the third emission region 154c side) in the light emitting element row from the first central axis CA1 of the first light flux controlling member 150. The simulation results for the emitted light are indicated by black squares (■). The light distribution of this light is controlled in a portion of the first light flux controlling member 150 closer to the center side (third emission region 154c side) in the light emitting element array than the first central axis CA1. Further, from the light emission center of the light emitting element 140 disposed below the first light flux controlling member 150, the end side (first emission region 154a side) in the light emitting element row from the first central axis CA1 of the first light flux controlling member 150. The simulation results for the emitted light are shown by black triangles (▲). The light distribution of the first light flux controlling member 150 is controlled at the end side (first emission region 154a side) of the light emitting element array from the first central axis CA1. In addition, from the light emission center of the light emitting element 140 disposed below the second light flux controlling member 160, one end side (fifth emission) in the light emitting element row from the second central axis CA2 of the second light flux controlling member 160. The simulation results for the light emitted to the region 164b side are indicated by white circles (◯).

  On the other hand, a simulation result of light whose light distribution is controlled by the first light flux control member 150 or the second light flux control member 160 in a virtual plane that includes the first central axis CA1 or the second central axis CA2 and extends in the y direction. Was the same. Therefore, in FIG. 5B, the light is emitted from the light emission center of the light emitting element 140 disposed below the first light flux control member 150 to one side in the y direction from the first central axis CA1 of the first light flux control member 150. Only the results for the emitted light are indicated by black triangles (▲).

  In these graphs, “first emission angle θ1” means the angle of light emitted from the light emission center of the light emitting element 140 with respect to the optical axis LA of the light emitting element 140. In addition, the “second emission angle θ2” is from the first light flux control member 150 or the second light flux control member 160 with respect to the optical axis LA of the light emitting element 140 (coincident with the first central axis CA1 or the second central axis CA2). It means the angle of emitted light. At this time, the light emitted from the first emission surface 154 or the second emission surface 164 is emitted in a direction parallel to the optical axis LA with the emission angle of the light emitted so as to approach the optical axis LA being a negative angle. The outgoing angle of the emitted light is 0 °, and the outgoing angle of the emitted light away from the optical axis LA is a positive angle. In these graphs, the first exit angle θ1 smaller than the first exit angle θ1 when the second exit angle θ2 has a peak value is incident on the first entrance surface 151 or the third entrance surface 161. The simulation result of the light to be shown is shown. For the angle range of the first emission angle θ1 that is larger than the first emission angle θ1 when the second emission angle θ2 has a peak value, a simulation result of light incident on the second incident surface 152 or the fourth incident surface 162 is shown. .

  FIG. 6 is a diagram illustrating an optical path of light in the surface light source device 110 according to the above-described embodiment until the irradiated member 120 is reached. In FIG. 6, hatching is omitted to show the optical path. Further, the substrate 130, the first flange 155a, the second flange 155b, the third flange 155c and the first support portion 156 of the first light flux controlling member 150, and the fourth flange 165a and the fifth flange 165b of the second light flux controlling member 160 are provided. The second support portion 166 is omitted because it does not affect the optical path. The distance (pitch) between the centers of the light emitting elements 140 is 15 mm, and the distance between the light emitting surface of the light emitting elements 140 and the irradiated member 120 is 50 mm.

  First, an optical path of light whose light distribution is controlled on the end side in the light emitting element array from the first central axis CA1 of the first light flux controlling member 150 will be described. As shown by the black triangle (θ) in FIG. 5A, the second emission angle θ2 of the light ray on the virtual plane along the x direction is a negative value regardless of the first emission angle θ1. That is, the light whose light distribution is controlled on the end side in the light emitting element row of the first light flux controlling member 150 is emitted from the first emission surface 154 toward the center side in the light emitting element row, as shown in FIG. Is done. Specifically, the light emitted from the light emitting element 140, incident on the second incident surface 152, and reflected on the first total reflection surface 153 mainly reaches the first emission region 154a. The light reaching the first emission region 154a is emitted from the first emission region 154a toward the center side of the light emitting element array. Further, the light emitted from the light emitting element 140 and incident on the first incident surface 151 mainly reaches the second emission region 154b. Among these, the light that has reached the region on the first emission region 154a side of the second emission region 154b is also emitted toward the center side in the light emitting element array, similarly to the first emission region 154a. The light includes light emitted from the light emitting element 140 at an emission angle of 5 to 20 °, and is converged by the positive power of the region on the first emission region 154a side of the second emission region 154b, while the light emitting element array Is emitted toward the center side. As described above, the emission region (the first emission region of the first light flux controlling member 150) closer to the end of the light emitting element array than the virtual surface, with the virtual surface including the first central axis CA1 and parallel to the y direction as a boundary. The light emitted from the first emission region 154a side of the first emission region 154a and the second emission region 154b is emitted toward the center side of the light emitting element array, that is, toward the center side of the irradiated member 120. For this reason, the emitted light from the surface light source device 110 is not irradiated to areas other than the irradiated member 120 (for example, a liquid crystal panel), and the light use efficiency can be prevented from being lowered.

  Next, an optical path of light whose light distribution is controlled on the center side (second light flux control member 160 side) in the light emitting element array from the first central axis CA1 of the first light flux control member 150 will be described. As shown by the black square (■) in FIG. 5A, the second emission angle θ2 of the light ray on the virtual plane along the x direction is a positive value regardless of the first emission angle θ1. That is, the light whose light distribution is controlled on the center side in the light emitting element row of the first light flux controlling member 150 is emitted from the first emission surface 154 toward the center side in the light emitting element row, as shown in FIG. The Specifically, the light emitted from the light emitting element 140, incident on the second incident surface 152, and reflected by the first total reflection surface 153 mainly reaches the third emission region 154c. At least a part of the light reaching the third emission region 154c is emitted toward the center side of the light emitting element array while being expanded by the negative power of the third emission region 154c. Further, the light emitted from the light emitting element 140 and incident on the first incident surface 151 mainly reaches the second emission region 154b. Among these, the light that has reached the region on the third emission region 154c side of the second emission region 154b is also emitted toward the center side of the light emitting element array in the same manner as the third emission region 154c. This light includes light emitted from the light emitting element 140 at an emission angle of 5 to 20 °, and is emitted toward the center side in the light emitting element array. As described above, the emission area (the third emission area 154c of the first light flux controlling member 150 and the emission area closer to the center of the light-emitting element array than the virtual plane with the virtual plane parallel to the y direction as a boundary including the first central axis CA1. The light emitted from the second emission region 154 b on the third emission region 154 c side) is emitted while being spread toward the center side of the light emitting element array, that is, the center side of the irradiated member 120. For this reason, it can prevent that a dark part generate | occur | produces in the area | region corresponding between the 1st light beam control member 150 and the 2nd light beam control member 160 in the to-be-irradiated member 120 (for example, liquid crystal panel).

  The emission area closer to the center in the light emitting element array than the virtual plane (the third emission area 154c and the third emission area of the second emission area 154b) with a virtual plane that includes the first central axis CA1 and parallel to the y direction as a boundary. The difference in function between the region on the 154c side) and the exit region (the region on the first exit region 154a side of the first exit region 154a and the second exit region 154b) is confirmed by the light beam shown in FIG. Can be done. The spread of the light flux until reaching the first emission surface 154 is the same on the center side and the end side in the light emitting element array. On the other hand, the light beam emitted from the first emission surface 154 is greatly expanded on the center side in the light emitting element array from the above-described virtual surface. The light beam emitted from the third emission region 154c is particularly greatly expanded. As described above, the third emission region 154c emits the light beam incident on the second incident surface 152 and reflected by the first total reflection surface 153 while diverging than before reaching the third emission region 154c. You can see that it works.

  Since the first exit surface 154 has no curvature in the y direction, the second exit angle θ2 in the imaginary plane along the y direction is −5 as indicated by a black triangle (▲) in FIG. 5B. Within the range of ~ 5 °. Therefore, although not particularly illustrated, when viewed with respect to a light beam on a virtual plane along the y direction, the light emitted from the first light flux controlling member 150 is emitted at an angle substantially parallel to the optical axis LA.

  Next, an optical path of light whose light distribution is controlled by the second light flux controlling member 160 will be described. As shown by a white circle (◯) in FIG. 5A, the second emission angle θ2 of the light ray on the virtual plane along the x direction is a negative value when the first emission angle θ1 is in the range of 0 to 25 °. One emission angle θ1 is a positive value in the range of 30 to 80 °. That is, the light whose light distribution is controlled by the second light flux controlling member 160 is emitted from the second emission surface 164 so as to spread as shown in FIG. Specifically, the light emitted from the light emitting element 140, incident on the fourth incident surface 162, and reflected on the second total reflection surface 163 reaches the fifth emission region 164b. At least a part of the light reaching the fifth emission region 164b is emitted away from the optical axis LA of the light emitting element 140 while being expanded by the negative power of the fifth emission region 164b. As described above, the light emitted from the fifth emission region 164b of the second light flux controlling member 160 is expanded toward the adjacent light flux controlling member (the first light flux controlling member 150 or the second light flux controlling member 160). Emitted. Therefore, it is possible to prevent a dark portion from being generated in a corresponding region between the second light flux control member 160, the first light flux control member 150, or the second light flux control member 160 in the irradiated member 120 (for example, a liquid crystal panel). Can do. Further, the light emitted from the light emitting element 140 and incident on the third incident surface 161 reaches the fourth emission region 164a. This light includes light emitted from the light emitting element 140 at an emission angle of 5 to 20 °. The light reaching the fourth emission region 164a is emitted so as to approach the optical axis LA of the light emitting element 140 while being converged by the positive power of the fourth emission region 164a. The light emitted from the fourth emission region 164a of the second light flux controlling member 160 is converged on the optical axis LA in front of the irradiated member 120 and reaches the irradiated member 120 with an appropriate spread. For this reason, it can prevent that a dark part generate | occur | produces in the area | region right above the 2nd light beam control member 160 in the to-be-irradiated member 120 (for example, liquid crystal panel).

  FIG. 7A is a graph showing the relationship between the emission angle of the emitted light from the light emitting element 140 and the relative luminous intensity. FIG. 7B is a graph showing the relationship between the emission angle of the emitted light from the first light flux controlling member 150 and the relative luminous intensity. FIG. 8A is a graph showing the relationship between the emission angle of the emitted light from the second light flux controlling member 160 and the relative luminous intensity. FIG. 8B shows the relationship between the emission angle of the emitted light from the two first light flux control members 150 and one second light flux control member 160 (surface light source device 110 shown in FIGS. 2 and 6) and the relative luminous intensity. It is a graph. In each graph, the horizontal axis indicates the emission angle (°), and the vertical axis indicates the relative luminous intensity (maximum value 1). Further, the luminous intensity distribution of the light rays on the virtual plane including the central axis (first central axis CA1 or second central axis CA2) of the light emitting element 140 and the light flux controlling member and along the x direction is indicated by a solid line. The luminous intensity distribution of the light beam on the imaginary plane including the central axis (first central axis CA1 or second central axis CA2) of the light flux controlling member and extending along the y direction is indicated by a broken line. In FIG. 7A, the solid line and the broken line completely overlap. 7B, the central side (second light flux controlling member 160 side) in the light emitting element array from the optical axis LA of the light emitting element 140 (first central axis CA1 of the first light flux controlling member 150) is a negative angle. The end side in the light emitting element array was set to a positive angle.

  When the light emitting element 140 having the light intensity distribution as shown in FIG. 7A is used, as shown in FIG. 7B, the peak of the light intensity distribution of the light whose light distribution is controlled by the first light flux controlling member 150 is the y direction. On the imaginary plane along the x direction, it was near 0 °, whereas on the imaginary plane along the x direction, it was around -5 °. In addition, the range of the emission angle of the light whose light distribution is controlled by the first light flux controlling member 150 is about −10 to + 10 ° on the virtual plane along the y direction, but on the virtual plane along the x direction. Then, it was about -30 to + 10 °. Also from these facts, it can be seen that the first light flux controlling member 150 disposed on the end side in the light emitting element array emits light while spreading toward the center side in the light emitting element array.

  Further, as shown in FIG. 8A, the peak of the luminous intensity distribution of the light whose light distribution is controlled by the second light flux controlling member 160 is one near 0 ° on the virtual plane along the y direction, On the virtual plane along the x direction, there were two near ± 5 °. This is because the fourth emission region 164a converges the light emitted from the light emitting element 140 at an emission angle of 5 to 20 °. In addition, the range of the emission angle of the light whose light distribution is controlled by the second light flux controlling member 160 is about −10 to 10 ° on the virtual plane along the y direction, but on the virtual plane along the x direction. Then, it was about -20 to 20 °. Also from this, the second light flux controlling member 160 disposed on the center side in the light emitting element array spreads light toward the adjacent light flux controlling member (the first light flux controlling member 150 or the second light flux controlling member 160). It can be seen that the light is emitted.

  As a result, as shown in FIG. 8B, the light emitted from the surface light source device 110 according to the present embodiment is emitted at an emission angle of −20 to + 20 ° on the virtual plane along the x direction, and y The light is emitted at an emission angle of −10 to + 10 ° on a virtual plane along the direction.

(Light distribution characteristics of surface light source device)
Next, the light distribution characteristics of the surface light source device 110 according to the above-described embodiment will be described.

  Here, the surface light source device 110 according to the present embodiment and the surface light source device that does not include any of the first light flux control member 150 and the second light flux control member 160 (hereinafter, also referred to as “surface light source device according to a comparative example”). The light distribution characteristics of) were simulated. In this simulation, first, the ratio of light reaching the irradiated member 120 is calculated from the light emitted from the surface light source device 110 according to the present embodiment and the surface light source device according to the comparative example, and the light use efficiency is calculated. Obtained. As described above, in the HUD, the surface light source device 110 can be used in combination with a projection optical system such as a projection lens. Therefore, in this simulation, the ratio of the light emitted from the surface light source device 110 according to the embodiment and the surface light source device according to the comparative example, and after passing through the irradiated member 120, further reaches the projection lens, Light utilization efficiency was obtained.

  The parameters for the simulation are as follows: the distance between the centers of the light emitting elements 140: 15 mm, the distance between the light emitting elements 140 and the irradiated member 120: 50 mm, the area of the irradiated member 120: 40 mm × 20 mm, the irradiated member 120 and the projection lens. The distance of the projection lens was 20 mm, the diameter of the projection lens was Φ100 mm, and the light capturing angle of the projection lens was 12 ° or less. At this time, the center of the irradiated member 120 (the intersection of two diagonal lines) is set to coincide with the optical axis LA of the central light emitting element 140 in the light emitting element array and the central axis CA2 of the second light flux controlling member 160. did.

  The simulation results are shown in Table 1. The light use efficiency means the ratio of the total luminous flux reaching the irradiated member 120 or the projection lens among the total luminous flux emitted from the light emitting element 140.

  As shown in Table 1, in the surface light source measure 110 according to the present embodiment, 74% of the light emitted from the light emitting element 140 can reach the irradiated member 120, and 57% of the light is a projection lens. It can be seen that it can be further reached. On the other hand, in the surface light source device according to the comparative example, only 8% of the light emitted from the light emitting element 140 can reach the irradiated member 120, and only 4% of the light can reach the projection lens. Recognize. From this result, in the surface light source device 110 according to the present embodiment, the light distribution from the light emitting element 140 is appropriately controlled by the first light flux control member 150 and the second light flux control member 160, and light can be used with high efficiency. You can see that

  FIG. 9 is a graph showing the illuminance distribution in the x direction and y direction of the light reaching the irradiated member 120 in the display device 100 according to the present embodiment. In FIG. 9, the illuminance distribution in the x direction is indicated by a solid line, and the illuminance distribution in the y direction is indicated by a broken line. The horizontal axis indicates the position of the irradiated member 120 from the center in the x direction and the y direction, and the vertical axis indicates the illuminance (lx) on the lower surface of the irradiated member 120. From this result, it can be seen that the surface light source device 110 according to the present embodiment can uniformly illuminate the irradiated member 120.

(effect)
As described above, in the first light flux controlling member 150 according to the present embodiment, it is possible to appropriately control the light distribution of the emitted light from the light emitting element 140 disposed at the end in the light emitting element array. Therefore, the surface light source device 110 and the display device 100 according to the present embodiment can suppress luminance unevenness and realize high light utilization efficiency. In addition, display device 100 according to the present embodiment can suppress display unevenness and achieve high light utilization efficiency.

  Although the display device 100 and the surface light source device 110 having the second light flux controlling member 160 have been described in the present embodiment, the display device and the surface light source device according to the present invention are light emitting elements included in a light emitting element array. When the number is two, the second light flux controlling member may not be provided. In this case, the shape of the region on the third emission region side of the second emission region can be appropriately designed according to the interval between the two adjacent first light flux control members.

  In the present embodiment, the surface light source device 110 and the display device 100 having one light emitting element array in which a plurality of light emitting elements 140 are arranged in a line along the x direction (first direction) have been described. However, the surface light source device and the display device according to the present invention may have two or more light emitting element arrays.

  The surface light source device according to the present invention is useful as a light source for a head-up display (HUD), for example. The display device according to the present invention is useful as, for example, a head-up display (HUD).

10 Surface light source device 11 Substrate 12 LED
DESCRIPTION OF SYMBOLS 13 Lens 14 Lens array 15 Diffuser 16 Boundary line 17 Concave part 18 Convex part 100 Display apparatus 110 Surface light source device 120 Irradiated member 130 Substrate 140 Light emitting element 150 First light flux control member 151 First incident surface 152 Second incident surface 153 First 1 Total reflection surface 154 1st exit surface 154a 1st exit area 154b 2nd exit area 154c 3rd exit area 155a 1st flange 155b 2nd flange 155c 3rd flange 156 1st support part 160 2nd light flux control member 161 3rd Incident surface 162 Fourth incident surface 163 Second total reflection surface 164 Second emission surface 164a Fourth emission region 164b Fifth emission region 165a Fourth flange 165b Fifth flange 166 Second support portion CA1 First central axis CA2 Second center Axis LA Optical axis

Claims (8)

In a surface light source device having at least one light emitting element array in which a plurality of light emitting elements are arranged in a line along the first direction, the center of the surface light source device is arranged on the light emitting element disposed at the end of the light emitting element array. A light flux controlling member disposed such that an axis is orthogonal to the first direction and coincides with an optical axis of the light emitting element;
A bottom surface of a rotationally symmetric recess having the central axis as a rotation axis, and a first incident surface on which at least a part of light emitted from the light emitting element is incident;
A second incident surface constituting a side surface of the recess;
A rotationally symmetric curved surface disposed around the concave portion and having the central axis as a rotation axis, the total reflection surface reflecting light incident on the second incident surface;
An exit surface disposed at a position intersecting with the central axis, and emitting light incident on the first incident surface and light incident on the second incident surface and reflected by the total reflection surface;
Have
An interval between the total reflection surfaces in a direction orthogonal to the central axis increases from the concave portion side toward the emission surface side,
The emission surface is arranged at a first emission region arranged on the end side in the light emitting element row, a second emission region arranged at a position intersecting with the central axis, and a center side in the light emitting device row. A third emission region,
In a cross section including the optical axis of the plurality of light emitting elements arranged on the light emitting element row,
The first emission region includes a surface on which light incident on the second incident surface and reflected by the total reflection surface reaches, incident on the second incident surface, and reflected on the total reflection surface And at least a part of the light is emitted while being refracted toward the center side of the light emitting element row with respect to the central axis,
The second emission region mainly includes a surface on which light incident on the first incident surface reaches,
The third emission region includes a surface on which light incident on the second incident surface and reflected by the total reflection surface reaches, and is incident on the second incident surface and reflected on the total reflection surface To emit while diverging,
Luminous flux control member. In a cross section including the optical axis of the plurality of light emitting elements arranged on the light emitting element row,
The second emission region includes a surface that is emitted from the light emitting element at an emission angle of 5 ° or more and 20 ° or less, and includes a surface on which light incident on the first incident surface arrives. Having a positive power with respect to at least a part of the light emitted at an emission angle of 20 ° or less and incident on the first incident surface;
The light flux controlling member according to claim 1.   The light flux controlling member according to claim 1, wherein the first incident surface has a positive power with respect to incident light.   4. The light flux controlling member according to claim 1, wherein the emission surface has no curvature in the first direction and a second direction orthogonal to the central axis. 5. A light emitting element array in which a plurality of light emitting elements are arranged in a line along the first direction;
A first light flux control disposed on the light emitting element disposed at an end of the light emitting element array so that a central axis thereof is orthogonal to the first direction and coincides with an optical axis of the light emitting element. Members,
Have
The first light flux controlling member is the light flux controlling member according to any one of claims 1 to 4, and is arranged so that the first emission region is located on an end side in the light emitting element array. Yes,
Surface light source device. A second central axis that is a central axis of the light emitting elements arranged on the light emitting element array other than the end is perpendicular to the first direction and coincides with the optical axis of the light emitting elements. A second light flux controlling member disposed;
The second light flux controlling member is
A bottom surface of a rotationally symmetric second recess having the second central axis as a rotation axis, and a third incident surface on which at least a part of light emitted from the light emitting element is incident;
A fourth incident surface constituting a side surface of the second recess;
A second symmetrical surface that is arranged to surround the second recess and is a rotationally symmetric curved surface having the second central axis as a rotational axis, and reflects light incident on the fourth incident surface;
A second emission surface arranged at a position intersecting with the second central axis and emitting light incident on the third incidence surface and light incident on the fourth incidence surface and reflected by the second total reflection surface When,
Have
An interval between the second total reflection surfaces in a direction orthogonal to the second central axis increases from the second recess side toward the second emission surface side,
The second emission surface includes a fourth emission region arranged at a position intersecting the second central axis, and two fifth emission regions arranged so as to sandwich the fourth emission region in the first direction. Including
The fourth emission region mainly includes a surface on which light incident on the third incident surface reaches,
The fifth emission region includes a surface on which light incident on the fourth incident surface and reflected by the second total reflection surface reaches, is incident on the fourth incident surface, and is reflected on the total reflection surface To emit while diverging
The surface light source device according to claim 5.   In the cross section perpendicular to the first direction and including the central axis, the curvature of the exit surface of the first light flux controlling member in the cross section including the central axis, and in the cross section orthogonal to the first direction and including the second central axis. The surface light source device according to claim 6, wherein a curvature of the second emission surface of the second light flux controlling member is the same. A surface light source device according to any one of claims 5 to 7,
A member to be irradiated with light emitted from the surface light source device; and
A display device.