JP2017092017A - Luminous flux control member, light emitting device, surface light source device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminous flux control member capable of suppressing color unevenness without using a wavelength conversion material.SOLUTION: A luminous flux control member includes: an incident surface; a first total reflection surface formed on the opposite side from the incident surface, and for reflecting one part of incident light into two directions substantially vertical to an optical axis of a light emitting element and, also, opposite from each other; two light guide parts for guiding the light which entered in the incident surface into the direction being separated from the incident surface and the first total reflection surface, at positions opposing to each other by sandwiching the incident surface and the first total reflection surface; two second total reflection surfaces arranged on both end parts of the light guide part, for allowing the light which entered the incident surface and reached directly to enter at equal to or greater than a critical angle and to reflect so as to be separated from a virtual flat surface with the virtual flat surface including the optical axis and a first virtual straight line being a boundary; and two emission surfaces formed on the outside surfaces of the two light guide parts and for emitting the light guided by the light guide parts to the outside.SELECTED DRAWING: Figure 5

Description

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

  In a transmissive image display device such as a liquid crystal display device or a signboard, a direct type surface light source device may be used as a backlight. In recent years, a direct type surface light source device having a plurality of light emitting elements as a light source has been used (for example, see Patent Document 1).

  The direct type light source device (surface light source device) described in Patent Document 1 is provided for a light source substrate, a plurality of light sources (light emitting elements) arranged on the light source substrate and emitting blue light, and a plurality of light sources. And a wavelength conversion sheet including a wavelength conversion substance such as a phosphor or a quantum dot, which is disposed via an air layer. In the surface light source device described in Patent Document 1, when blue light emitted from the light source enters the wavelength conversion sheet, part of the blue light is converted into red light and green light by the wavelength conversion material. The Blue light, red light and green light are mixed to form white light, which is emitted from the wavelength conversion sheet.

Japanese Patent Laying-Open No. 2015-035336

  However, since the surface light source device described in Patent Document 1 uses an expensive wavelength conversion material such as a phosphor or a quantum dot, there is a problem that the manufacturing cost increases.

  As a means for reducing the manufacturing cost, it is conceivable to use a combination of a plurality of light emitting elements having different colors of the emitted light, instead of using the wavelength changing materials for generating the three primary colors. However, when a plurality of light emitting elements having different colors of emitted light are used in combination, it is necessary to mix colors without color unevenness. In particular, when the surface light source device is thinned or the light emitting elements (light sources) are widened, it is difficult to sufficiently mix colors, and color unevenness is likely to occur.

  Therefore, an object of the present invention is to provide a light flux controlling member that can suppress color unevenness without using a wavelength converting substance. Another object of the present invention is to provide a light emitting device, a surface light source device, and a display device having the light flux controlling member.

  A light flux controlling member according to the present invention is a light flux controlling member that controls light distribution of light emitted from a light emitting element, and includes an incident surface on which light emitted from the light emitting element is incident, and the incident surface sandwiching the incident surface. A first total reflection formed at a position facing the light emitting element and reflecting a part of light incident from the incident surface in two directions which are substantially perpendicular to the optical axis of the light emitting element and opposite to each other. A part of the light incident from the incident surface and the light reflected by the first total reflection surface at a position facing each other across the surface and the incident surface and the first total reflection surface. Two light guides for guiding light in a direction away from the total reflection surface and ends of the two light guides, respectively, intersect with the optical axis and the optical axis, and the two light guides extend. A virtual plane including the first virtual straight line along the existing direction is defined as a boundary. Two second total reflection surfaces that reflect light incident on the incident surface and directly reaching the incident surface at an angle greater than a critical angle so as to be away from the virtual plane, and outer surfaces of the two light guides, respectively. And two emission surfaces for emitting the light guided by the light guide part to the outside.

  Moreover, the light-emitting device which concerns on this invention has a light-emitting element and the light beam control member which concerns on this invention arrange | positioned so that the optical axis of the said light-emitting element may be crossed.

  The surface light source device according to the present invention includes a plurality of light emitting devices according to the present invention, and a light diffusion plate that diffuses and transmits the light emitted from the light emitting devices, and the plurality of light emitting devices are The light emitting device rows are arranged so that the first virtual line is along the first direction, and the light emitting device rows are arranged in a plurality of rows in a second direction perpendicular to the first direction.

  Moreover, the display apparatus which concerns on this invention has the surface light source device which concerns on this invention, and the to-be-irradiated member irradiated with the light radiate | emitted from the said surface light source device.

  ADVANTAGE OF THE INVENTION According to this invention, when the light emitting element from which the color of each emitted light differs is used as the light source, the light beam control member which can suppress a color nonuniformity without using a wavelength conversion substance can be provided. Further, it is possible to provide a light emitting device, a surface light source device, and a display device that have the light flux controlling member and have little color unevenness.

1A and 1B are diagrams showing a configuration of a surface light source device according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the surface light source device according to the first embodiment. FIG. 3 is a cross-sectional view of the light emitting device according to the first embodiment. 4A to 4C are diagrams showing the configuration of the light flux controlling member according to the first embodiment. 5A and 5B are diagrams showing the configuration of the light flux controlling member according to the first embodiment. 6A and 6B are perspective views of the light flux controlling member main body according to Embodiment 1. FIG. 7A to 7C are diagrams showing the configuration of the light flux controlling member main body according to Embodiment 1. FIG. 8A and 8B are diagrams showing the configuration of the light flux controlling member body according to Embodiment 1. FIG. FIGS. 9A and 9B are views showing the arrival positions of the light emitted from the light emitting element at an emission angle of 30 ° and controlled by the light flux controlling member to the light diffusion plate and the substrate. 10A and 10B are optical path diagrams in a light emitting device of light emitted from the light emitting element at an emission angle of 30 °. FIGS. 11A and 11B are views showing the arrival positions of light emitted from the light emitting element at an emission angle of 45 ° and controlled by the light flux controlling member to the light diffusion plate and the substrate. 12A and 12B are optical path diagrams in a light emitting device of light emitted from the light emitting element at an emission angle of 45 °. FIGS. 13A and 13B are views showing the arrival positions of light emitted from the light emitting element at an emission angle of 60 ° and controlled by the light flux controlling member to the light diffusion plate and the substrate. 14A and 14B are optical path diagrams in a light emitting device of light emitted from the light emitting element at an emission angle of 60 °. FIGS. 15A and 15B are views showing the positions where light emitted from the light emitting element at an emission angle of 75 ° and controlled by the light flux controlling member reaches the light diffusion plate and the substrate. 16A and 16B are optical path diagrams in a light emitting device of light emitted from the light emitting element at an emission angle of 75 °. 17A to 17D are optical path diagrams in a light emitting device according to a comparative example. 18A and 18B are plan views of a light flux controlling member according to a modification of the first embodiment of the present invention. 19A to 19C are diagrams showing the configuration of the light flux controlling member according to the second embodiment. 20A to 20C are diagrams showing the configuration of the light flux controlling member according to the second embodiment. 21A to 21C are diagrams illustrating the configuration of the scattering member. FIG. 22 is a diagram for explaining the characteristics of the scattering member of the light flux controlling member according to the second embodiment. FIGS. 23A and 23B are diagrams showing arrival positions on the light diffusion plate of light emitted from the light emitting elements at the emission angles of 15 ° and 20 °. 24A and 24B are views showing the arrival positions of the light emitted from the light emitting elements at the emission angles of 25 ° and 30 ° on the light diffusion plate. 25A and 25B are graphs showing the luminance distribution on the light diffusion plate. 26A to 26C are diagrams showing a configuration of a light flux controlling member according to a modification of the second embodiment. 27A to 27C are diagrams showing a configuration of a light flux controlling member according to a modification of the second embodiment.

  Hereinafter, a light flux controlling member, a light emitting device, a surface light source device, and a display device of the present invention will be described in detail with reference to the drawings. In the following description, a surface light source device suitable for a backlight of a liquid crystal display device will be described as a representative example of the surface light source device of the present invention. These surface light source devices can be used as a display device by combining with an irradiated member (for example, a liquid crystal panel) irradiated with light from the surface light source device.

[Embodiment 1]
(Configuration of surface light source device)
1 and 2 are diagrams showing the configuration of the surface light source device 100 according to Embodiment 1 of the present invention. FIG. 1A is a plan view of the surface light source device 100, and FIG. 1B is a front view. 2 is a cross-sectional view taken along line AA shown in FIG. 1B. FIG. 3 is a cross-sectional view of the light emitting device 130. 4 to 8 are diagrams showing the configuration of the light flux controlling member 150 according to the first embodiment. 4A is a plan view of the light flux controlling member 150, FIG. 4B is a front view, and FIG. 4C is a bottom view. 5A is a right side view of the light flux controlling member 150, and FIG. 5B is a cross-sectional view taken along line AA shown in FIG. 4A. 6A is a perspective view of the light flux controlling member 150 (light flux controlling member main body) from which the scattering member 157 has been removed as viewed from above, and FIG. 6B shows the bottom surface 158 of the light flux controlling member 150 from which the scattering member 157 has been removed facing up It is a perspective view in the case of facing. 7A is a plan view of the light flux controlling member 150 with the scattering member 157 removed, FIG. 7B is a front view, and FIG. 7C is a bottom view. 8A is a right side view of the light flux controlling member 150 with the scattering member 157 removed, and FIG. 8B is a cross-sectional view taken along line AA shown in FIG. 7A.

  As shown in FIGS. 1 and 2, the surface light source device 100 includes a housing 110, a substrate 120, a plurality of light emitting devices 130, and a light diffusing plate 140.

  The housing 110 is a rectangular parallelepiped box in which an opening is provided on at least a part of one surface for housing the substrate 120 and the plurality of light emitting devices 130 therein. The housing 110 includes a top plate, a bottom plate facing the top plate, and four side plates that connect the top plate and the bottom plate. A rectangular opening serving as a light emitting region is formed in the top plate. This opening is closed by the light diffusing plate 140. The size of the opening corresponds to the size of the light emitting area (light emitting surface) formed in the light diffusion plate 140, and is, for example, 400 mm × 700 mm (32 inches). The bottom plate and the light diffusion plate 140 are arranged in parallel. The height (space thickness) from the surface of the bottom plate to the light diffusion plate 140 is not particularly limited, but is about 10 to 25 mm. The housing 110 is made of, for example, a resin such as polymethyl methacrylate (PMMA) or polycarbonate (PC), or a metal such as stainless steel or aluminum.

  The substrate 120 is a flat plate for arranging the light emitting device 130 in the casing 110 at a predetermined interval. The substrate 120 is disposed on the bottom plate of the housing 110. The number of the light emitting devices 130 disposed on the substrate 120 is not particularly limited. The number of the light emitting devices 130 arranged on the substrate 120 is appropriately set based on the size of the light emitting area (light emitting surface) defined by the opening of the housing 110. The surface of the substrate 120 on which the light emitting device 130 is disposed is configured to reflect the reached light toward the light diffusion plate 140.

  Each of the plurality of light emitting devices 130 includes a plurality of light emitting elements 131 and a light flux controlling member 150. The plurality of light emitting devices 130 are arranged such that the optical axes OA of the light emitted from the light emitting elements 131 are along the normal to the surface of the substrate 120 (see FIG. 3). The plurality of light emitting devices 130 are arranged as a light emitting device row 130L so that the long axis (first imaginary straight line to be described later) of the light emitting device 130 (light flux controlling member 150) is along the first direction D1. A plurality of the light emitting device rows 130L are arranged in the second direction D2 orthogonal to the first direction D1 (see FIG. 2). The light emitting device 130 is another light emitting device included in the light emitting device row 130L adjacent to the light emitting device row 130L including the light emitting device 130 in the second direction D2 when viewed in the second direction D2. It is arranged so as to overlap 130. Here, the “optical axis of the light emitting element” refers to the traveling direction of light at the center of the three-dimensional light beam from the central light emitting element 131 among the plurality of light emitting elements 131 constituting the light emitting element array 131L of the light emitting device 130. say.

  The light emitting element 131 is a light source of the surface light source device 100 (and the light emitting device 130). The light emitting element 131 is disposed on the substrate 120. The light emitting element 131 is, for example, a light emitting diode (LED). The number of light emitting elements 131 included in one light emitting device 130 is one or two or more. In the present embodiment, the number of light emitting elements 131 included in one light emitting device 130 is three. Moreover, the color of the emitted light emitted from each light emitting element 131 is not particularly limited. Furthermore, in the light emitting device 130 having the plurality of light emitting elements 131, the colors of the emitted light emitted from the respective light emitting elements 131 may be different from each other, or all may be the same. In the present embodiment, one light emitting device 130 includes a light emitting element 131r that emits red light, a light emitting element 131g that emits green light, and a light emitting element 131b that emits blue light. In the light emitting device 130, the three light emitting elements 131r, 131g, and 131b are arranged along the second direction D2 perpendicular to the first direction D1 so as to form the light emitting element row 131L (see FIG. 2). ).

  The arrangement order of the plurality of light emitting elements 131 in the light emitting device 130 may be the same as the arrangement order of the plurality of light emitting elements 131 in another light emitting device 130 adjacent in the first direction D1 or the second direction D2. , May be different. In the present embodiment, the arrangement order of the plurality of light emitting elements 131 in the two light emitting devices 130 adjacent in the second direction D2 is the same. On the other hand, the arrangement order of the light emitting elements 131 in the two light emitting devices 130 adjacent in the first direction D1 is different.

  Specifically, in a certain light emitting device 130, in the second direction D2, a light emitting element 131b that emits blue light, a light emitting element 131g that emits green light, and a light emitting element 131r that emits red light. Are arranged in order. In the light emitting device 130 adjacent to the light emitting device 130 in the second direction D2, the arrangement order of the light emitting elements 131 is the same.

  On the other hand, in the light emitting device 130 adjacent to the light emitting device 130 in the first direction D1, the light emitting element 131r that emits red light, the light emitting element 131g that emits green light, and the light emission that emits blue light. The elements 131b are arranged in order.

  The light flux controlling member 150 controls the light distribution of the light emitted from the light emitting element 131. As shown in FIGS. 4 to 8, the light flux controlling member 150 includes an incident surface 151, a first total reflection surface 152, two light guides 153, two second total reflection surfaces 154, and two It has an emission surface 155, leg portions 156, and scattering members 157.

  The incident surface 151 allows a part of the light emitted from the light emitting element 131 to enter. The incident surface 151 is an inner surface of the first recess 159 formed at the center of the bottom surface (surface on the light emitting element 131 side) 158 of the light flux controlling member 150. The shape of the inner surface of the first recess 159 is not particularly limited. The inner surface of the first recess 159 may be a curved surface not including an edge, such as a hemispherical shape or a semi-ellipsoidal shape, or may be a surface including an edge having a top surface and side surfaces. In the present embodiment, the inner surface of first recess 159 has a top surface and side surfaces.

  The first total reflection surface 152 is disposed on the opposite side (light diffusion plate 140 side) to the light emitting element 131 with the incident surface 151 interposed therebetween. The first total reflection surface 152 has a part of the light incident from the incident surface 151 approximately perpendicular to the optical axis OA of the light emitting element 131 (the central axis CA of the light flux controlling member 150) and opposite to each other. Reflect in one direction. The first total reflection surface 152 intersects with the optical axis OA and the optical axis OA, and the central axis CA is a cross-section taken along a first virtual plane including a first virtual line along the direction in which the two light guide portions 153 extend. The height from the bottom surface 158 (the substrate 120) is increased toward the both ends. More specifically, the first total reflection surface 152 is formed so that the slope of the tangent gradually decreases from the central axis CA toward the end in the cross section cut along the first imaginary plane.

  The two light guides 153 are formed at positions facing each other with the incident surface 151 and the first total reflection surface 152 interposed therebetween. The light guide unit 153 emits a part of the light incident on the incident surface 151 and the light reflected on the first total reflection surface 152 little by little while guiding the light. The surface of the light guide unit 153 on the light diffusion plate 140 side functions as an emission surface 155 that emits the guided light to the outside. In the light guide unit 153, scatterers such as beads may be dispersed from the viewpoint of making the amount of light emitted from the emission surface 155 uniform.

  The two second total reflection surfaces 154 are arranged at the end portions (the end portions away from the central axis CA) of the two light guide portions 153, respectively. The second total reflection surface 154 is incident on the incident surface 151 and directly reaches the first virtual plane with the first virtual plane including the optical axis OA (center axis CA) and the first virtual straight line as a boundary. Is incident and reflected at an angle greater than the critical angle. The shape of the second total reflection surface 154 is not particularly limited as long as a part of the light incident on the incident surface 151 is incident at an angle greater than the critical angle. In the present embodiment, the shape of the second total reflection surface 154 is from the end of the light guide 153 toward the optical axis OA (center axis CA) in a cross section cut along a second imaginary plane perpendicular to the optical axis OA. The two inclined surfaces 154a and 154a formed so as to approach the first virtual plane are included. In other words, in the present embodiment, the second total reflection surface 154 is the two inner surfaces facing each other of the V-grooves arranged in the direction along the optical axis OA (center axis CA) on the end surface of the light guide unit 153. is there. A part of the light traveling through the light guide unit 153 reaches the second total reflection surface 154. The light reaching the second total reflection surface 154 is incident and reflected at various angles. At this time, the red, blue, and green colors emitted from the light emitting element 131 are mixed by entering and reflecting on the second total reflection surface 154.

  The emission surface 155 is disposed at a position away from the first total reflection surface 152 with respect to the central axis CA in the extending direction of the first virtual line. The light exiting surface 155 is incident on the incident surface 151, is reflected by the first total reflection surface 152, then travels through the light guide unit 153, and is incident on the incident surface and is not reflected by the first total reflection surface 152 and is guided. The light that has traveled through the light unit 153 and the light that has entered the incident surface, travels through the light guide unit 153 without being reflected by the first total reflection surface 152, and exits the light that has been totally reflected by the second total reflection surface 154 to the outside. Let Further, the exit surface 155 may be subjected to a light diffusion process (for example, a roughening process).

  The shape of the light guide unit 153 is not particularly limited. In the present embodiment, the light guide portion 153 is a substantially rod-shaped member. The cross-sectional area of the light guide unit 153 in the minor axis direction is not particularly limited. In the present embodiment, the cross-sectional area of the light guide portion 153 in the minor axis direction is from the first total reflection surface 152 to the end portion on the central axis CA side of the second total reflection surface 154 from the first total reflection surface 152. It is formed so as to become smaller as it goes away. Further, the two light guide portions 153 are connected by two reinforcing members 160. Two legs 156 are arranged below the two reinforcing members 160. Further, guide engaging grooves 162 are formed on the side surfaces of the two light guide portions 153, respectively.

  In addition, second recesses 161 are respectively formed on the bottom surface (surface on the light emitting element 131 side) 158 of the light guide portion 153. By forming the second recess 161, the occurrence of sink marks during injection molding can be suppressed, and the manufacturing cost can be reduced. The two second recesses 161 are both formed along the long axis direction of the light flux controlling member 150 (the extending direction of the first imaginary straight line), but are not in communication with the first recess 159. The size and shape of the second recess 161 are formed so that a part of the light emitted from the light emitting element 131 can reach the second total reflection surface 154 directly, and the light flux controlling member 150. If the intensity | strength requested | required by this can be ensured, it will not specifically limit. Further, in the present embodiment, the planar view shape and depth of the second recess 161 are not particularly limited as long as the above-described functions can be exhibited, and can be set as appropriate. In addition, when shape | molding the light beam control member 150 by injection molding, it is preferable to form the 2nd recessed part 161 in the site | part which may generate | occur | produce a sink.

  The reinforcing member 160 improves the strength of the light flux controlling member 150. The position and shape of the reinforcing member 160 are not particularly limited as long as the function of the first total reflection surface 152 of the light flux controlling member 150 is not significantly impaired and the strength of the light flux controlling member 150 can be improved. In the present embodiment, the reinforcing member 160 is disposed on the bottom surface (surface on the light emitting element 131 side) 158 side of the light flux controlling member 150 and connects the light guide portions 153 to each other.

  The guide engagement grooves 162 are disposed at positions away from the reinforcing member 160 with respect to the central axis CA in the direction along the first imaginary straight line. The guide engaging groove 162 is a groove for positioning the scattering member 157 with respect to the light flux controlling member 150 by engaging an engaging protrusion 164 of the scattering member 157 described later.

  The scattering member 157 is disposed on the opposite side of the light emitting element 131 with the incident surface 151 interposed therebetween. The scattering member 157 is a separate member from the light flux controlling member main body including the incident surface 151, the first total reflection surface 152, the light guide unit 153, the second total reflection surface 154, and the output surface 155. The scattering member 157 mainly transmits light that is transmitted without being reflected by the first total reflection surface 152 while diffusing. The shape of the scattering member 157 is not particularly limited as long as the above function can be exhibited. Examples of the shape of the scattering member 157 include a semi-cylindrical shape and a bell-like shape (inverted U shape). In the present embodiment, the shape of the scattering member 157 is a bell-like shape. Further, the size of the scattering member 157 is not particularly limited as long as the above function can be exhibited. The scattering member 157 may be disposed so as to cover only the upper part of the first total reflection surface 152, or may be formed so as to cover the first total reflection surface 152 and the light guide unit 153. In the present embodiment, the scattering member 157 is formed so as to cover the first total reflection surface 152, a part of the emission surface 155, and the end of the second total reflection surface 154 on the central axis CA side. . On the inner surface of the scattering member 157, a plurality of prism rows 163 having a substantially triangular or semicircular cross-sectional shape are arranged. An engaging protrusion 164 that engages with the guide engaging groove 162 is disposed at the end of the scattering member 157 on the light emitting element 131 side.

  The material of the light flux controlling member 150 is not particularly limited as long as it can transmit light having a desired wavelength. For example, the material of the light flux controlling member 150 is a light transmissive resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), and epoxy resin (EP), or glass.

  The light diffusion plate 140 is disposed so as to close the opening of the housing 110. The light diffusing plate 140 is a plate-like member having a light diffusing property, and transmits the light emitted from the light flux controlling member 150 while diffusing it. Usually, the light diffusing plate 140 is approximately the same size as an irradiated member such as a liquid crystal panel. For example, the light diffusion plate 140 is formed of a light transmissive resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), styrene / methyl methacrylate copolymer resin (MS). In order to impart light diffusibility, fine irregularities are formed on the surface of the light diffusion plate 140, or light diffusers such as beads are dispersed inside the light diffusion plate 140.

(simulation)
Next, in the light emitting device 130, a simulation was performed on the arrival position and the optical path of the light emitted from the light emitting element 131 arranged in the center of the light emitting element row 131L.

  First, the arrival position of the light, which is emitted from the light emitting element 131 at each emission angle and whose traveling direction is controlled by the light flux controlling member 150, to the light diffusion plate 140 and the substrate 120 was simulated. In the simulation, the light emitting device 130 in which the light flux controlling member 150 in which the scattering member 157 is assembled is fixed to the substrate 120 on which the three light emitting elements 131 are fixed. The distance between the substrate 120 and the light diffusing plate 140 was 12 mm. Further, among the three light emitting elements 131, only one light emitting element 131 arranged in the central portion was turned on. In this simulation, the optical path in the light emitting device 130 is symmetrical in the horizontal direction (major axis direction) and the vertical direction (minor axis direction) of the drawing with the central axis CA in FIG. 4A as the center. The arrival position of light emitted in the upper right direction with respect to the central axis CA was simulated. In addition, simulation was performed with respect to arrival positions of light emitted at five kinds of emission angles of 30 °, 45 °, 60 °, and 75 ° with respect to the optical axis OA. For each emission angle, in a cross section cut by a second imaginary plane perpendicular to the optical axis OA, light parallel to the first imaginary line is defined as 0 °, and the angles with respect to the first imaginary line are 0 °, 5 °, 10 ° The simulation was performed on the arrival positions of seven types of light (°, 15 °, 20 °, 25 °, and 30 ° (28 types in total)). For comparison, a light emitting device having a light flux controlling member (not shown) that does not have the second total reflection surface 154 (hereinafter also referred to as “light emitting device according to a comparative example”) was similarly simulated.

  9, 11, 13, and 15 are views showing the positions where the light emitted from the light emitting element 131 at each emission angle and controlled by the light flux controlling member 150 reaches the light diffusion plate 140 and the substrate 120.

  FIG. 9A is a diagram showing the arrival position of the light emitted from the light emitting element at an emission angle of 30 ° and controlled by the light flux controlling member, and FIG. 9B shows the light to the substrate 120. It is the figure which showed the arrival position of. FIG. 11A is a diagram showing the arrival position of the light emitted from the light emitting element at an emission angle of 45 ° and controlled by the light flux controlling member, and FIG. 11B shows the light to the substrate 120. FIG. FIG. 13A is a diagram showing the arrival position of light emitted from the light emitting element at an emission angle of 60 ° and controlled by the light flux controlling member, and FIG. 13B shows the light to the substrate 120. It is the figure which showed the arrival position of. FIG. 15A is a view showing the arrival position of the light emitted from the light emitting element at an emission angle of 75 ° and controlled by the light flux controlling member, and FIG. 15B shows the light to the substrate 120. It is the figure which showed the arrival position of.

  9, 11, 13 and 15, the horizontal axis and the vertical axis indicate the distance (mm) in the direction perpendicular to the optical axis OA from the light emitting point (the center of the light emitting element 131). 9, 11, 13 and 15, the position of the light emitting device 130 when viewed in plan is indicated by a dotted line. 9, 11, 13, and 15 indicate the arrival position of the light emitted from the light emitting device 130 according to the present embodiment, and the black triangular symbol is emitted from the light emitting device according to the comparative example. The black light symbol indicates the light arrival position when only the light emitting element 131 is disposed on the substrate 120.

  Next, an optical path in the light emitting device 130 of light emitted from the light emitting element 131 at each emission angle was simulated. In this simulation, the number of light rays in a plane cut by the second virtual plane is different from the above-described simulation. In the present specification, only the results when the emission angles are 45 ° and 75 ° are shown for the light emitting device according to the comparative example.

  10, 12, 14 and 16 are optical path diagrams in the light emitting device 130 of light emitted from the light emitting element 131 at each emission angle. FIG. 17 is an optical path diagram of the light emitting device according to the comparative example. FIG. 10A is an optical path diagram when the light emitting device 130 for light emitted from the light emitting element 131 at an emission angle of 30 ° is viewed from the front, and FIG. 10B is an optical path diagram when viewed in plan. FIG. 12A is an optical path diagram when the light emitting device 130 for light emitted from the light emitting element 131 at an emission angle of 45 ° is viewed from the front, and FIG. 12B is an optical path diagram when viewed in plan. 14A is an optical path diagram when the light emitting device 130 of the light emitted from the light emitting element 131 at an emission angle of 60 ° is viewed from the front, and FIG. 14B is an optical path diagram when viewed in plan. FIG. 16A is an optical path diagram when the light emitting device 130 of light emitted from the light emitting element 131 at an emission angle of 75 ° is viewed from the front, and FIG. 16B is an optical path diagram when viewed in plan. FIG. 17A is an optical path diagram when a front view of a light emitting device according to a comparative example of light emitted from the light emitting element 131 at an emission angle of 45 °, and FIG. 17B is an optical path diagram when viewed in plan. FIG. 17C is an optical path diagram when a light emitting device according to a comparative example of light emitted from the light emitting element 131 at an emission angle of 75 ° is viewed from the front, and FIG. 17D is an optical path diagram when viewed in plan.

  As shown in FIG. 9B and FIGS. 10A and 10B, when the emission angle is 30 °, the light emitted from the light emitting device 130 according to the present embodiment and the light emitted from the light emitting device according to the comparative example are It was found that both reached the substrate 120. Moreover, the light emitted from the light emitting device according to the comparative example was emitted in a direction along the first virtual line. On the other hand, it was found that the light emitted from the light emitting device 130 according to the present embodiment is emitted in a direction perpendicular to the optical axis OA and the first virtual line. Although the simulation result is not particularly shown, when three light emitting elements 131 having different colors of emitted light are arranged in the light emitting device 130 and the three light emitting elements 131 are turned on, the light emitting elements 131 The emitted light is mixed by crossing the optical paths. Accordingly, since the mixed color light reaches the light diffusion plate 140, color unevenness can be suppressed.

  As shown in FIG. 11B, FIG. 12A, B and FIGS. 17A, B, when the emission angle is 45 °, the light emitted from the light emitting device 130 according to the present embodiment and the light emitting device according to the comparative example It was found that the emitted light mainly reaches the substrate 120. Further, it has been found that the light emitted from the light emitting device 130 according to the present embodiment is emitted in a direction perpendicular to the optical axis OA and the first virtual line. On the other hand, the light emitted from the light emitting device according to the comparative example was emitted in a direction along the first virtual straight line. Note that, when the emission angle is 45 °, the light emitted from the light emitting device 130 according to the present embodiment is emitted from the light emitting device 130 according to the present embodiment when the emission angle is 30 °. It was found that the light was emitted toward the central axis CA as compared with the light (see FIG. 11B). Also in this case, in the light emitting device 130 in which the three light emitting elements 131 are lit, the light emitted from each light emitting element 131 is mixed by crossing the optical paths. Therefore, the mixed color light reaches the light diffusion plate 140.

  As shown in FIG. 13B and FIGS. 14A and B, when the emission angle is 60 °, the light emitted from the light emitting device 130 according to the present embodiment and the light emitted from the light emitting device according to the comparative example It has been found that more light reaches the light diffusion plate 140 than light that reaches the substrate 120. Further, it has been found that the light emitted from the light emitting device 130 according to the present embodiment is emitted in a direction perpendicular to the optical axis OA and the first virtual line. On the other hand, it was found that the light emitted from the light emitting device according to the comparative example was emitted in a direction along the first imaginary straight line. Also in this case, in the light emitting device 130 in which the three light emitting elements 131 are lit, the light emitted from each light emitting element 131 is mixed by crossing the optical paths. Therefore, the mixed color light reaches the light diffusion plate 140.

  As shown in FIGS. 15B, 16B, 17C, and 17D, when the emission angle is 75 °, the light emitted from the light emitting device 130 according to the present embodiment and the light emitting device according to the comparative example are emitted. It has been found that more light reaches the substrate 120 than light reaching the light diffusion plate 140. Further, it has been found that the light emitted from the light emitting device 130 according to the present embodiment is emitted in a direction perpendicular to the optical axis OA and the first virtual line. On the other hand, it was found that the light emitted from the light emitting device according to the comparative example was emitted in a direction along the optical axis OA and the first imaginary straight line. Also in this case, in the light emitting device 130 in which the three light emitting elements 131 are lit, the light emitted from each light emitting element 131 is mixed by crossing the optical paths. Therefore, the mixed color light reaches the light diffusion plate 140.

  9A, FIG. 11A, FIG. 13A, and FIG. 15A, when only the light emitting element 131 is fixed to the substrate 120, all the light emitted from the light emitting element 131 reaches the light diffusion plate 140. I understood that.

  Further, as shown in FIGS. 9A, 11A, 13A, and 15A, it is understood that the light emitted from the light emitting element 131 is emitted in the first direction D1 and the second direction D2. . In addition, the light flux controlling member according to the comparative example functions to suppress emission in the second direction. When the emission in the second direction D2 is suppressed as in the light flux controlling member according to the comparative example, a dark portion is likely to be generated between the light emitting devices 130 in the second direction D2. Therefore, in the light flux controlling member 150 according to the present invention, the second total reflection surface 154 is controlled so that a part of the light traveling through the light guide unit 153 is emitted in the second direction. Yes. Thereby, generation | occurrence | production of the dark part which tends to arise between the light-emitting devices 130 in the 2nd direction D2 is suppressed.

(effect)
As described above, since light flux controlling member 150 according to the present embodiment has two second total reflection surfaces 154, light traveling through light guide unit 153 is controlled so as to be separated from the first virtual plane. Further, the light emitted from each light emitting element 131 in the light emitting device 130 crosses each other and reaches the light diffusion plate 140. Accordingly, even when a plurality of light emitting elements 131 having different colors of emitted light are used as light sources, the colors emitted from the respective light emitting elements 131 can be mixed. Therefore, in the light emitting device 130, the surface light source device 100, and the display device having the light flux controlling member 150, generation of dark portions can be suppressed and color unevenness can be suppressed.

(Modification)
18A and 18B are views for explaining the second total reflection surface of the light flux controlling member according to the modification of the embodiment of the present invention. FIG. 18A is a plan view of a light flux controlling member 150 ′ according to Modification 1 with the scattering member 157 removed, and FIG. 18B is a plan view of a light flux controlling member 150 ″ according to Modification 2 with the scattering member 157 removed. 18A, the cross-sectional shape of the second total reflection surface 154 ′ cut along the second imaginary plane may be a curved line that protrudes toward the first imaginary line. As shown, the cross-sectional shape of the second total reflection surface 154 ″ cut along the second imaginary plane may be a curve that is convex toward the first imaginary line. In addition, the cross-sectional shape of the second total reflection surface 154 ″ cut along the first virtual plane and the third virtual plane orthogonal to the second virtual plane may be a curved line that protrudes toward the bottom surface 158 or the bottom surface 158 side. It may be a concave curve.

  In the above embodiment, the light flux controlling member 150 includes the incident surface 151, the first total reflection surface 152, the two light guides 153, the two second total reflection surfaces 154, and the two output surfaces 155. In addition, the leg portion 156 and the scattering member 157 are provided, but the scattering member 157 may not be provided. That is, the light flux controlling member includes the incident surface 151, the first total reflection surface 152, the two light guide portions 153, the two second total reflection surfaces 154, the two output surfaces 155, and the leg portions 156. It may be configured. Even in this case, the occurrence of dark portions in the second direction D2 can be suppressed and color unevenness can be suppressed.

[Embodiment 2]
The surface light source device according to Embodiment 2 can further suppress luminance unevenness on the light diffusion plate 140 in the second direction D2. The surface light source device according to the second embodiment is different from the surface light source device 100 according to the first embodiment in the configuration of the light flux controlling member 250 of the light emitting device. Therefore, the same components as those of the surface light source device 100 according to Embodiment 1 are denoted by the same reference numerals, and the description thereof is omitted.

(Configuration of surface light source device)
The surface light source device according to Embodiment 2 includes a housing 110, a substrate 120, a plurality of light emitting devices 130, and a light diffusing plate 140. The plurality of light emitting devices 130 are arranged as a light emitting device array 130L so that the long axis of the light emitting device 130 (light flux controlling member 250) is along the first direction D1. A plurality of the light emitting device rows 130L are arranged in the second direction D2 (see FIG. 2). The light emitting device 130 is another light emitting device included in the light emitting device row 130L adjacent to the light emitting device row 130L including the light emitting device 130 in the second direction D2 when viewed in the second direction D2. It is arranged so as to overlap 130. Furthermore, the plurality of light emitting device rows 130L are arranged so that the interval between two adjacent light emitting device rows 130L is constant in the second direction D2.

(Configuration of luminous flux control member)
19-22 is a figure which shows the structure of the light beam control member 250 based on Embodiment 2. FIG. 19A is a plan view of the light flux controlling member 250, FIG. 19B is a front view, and FIG. 19C is a bottom view. 20A is a right side view of the light flux controlling member 250, FIG. 20B is a cross-sectional view taken along the line BB shown in FIG. 19B, and FIG. 20C is a cross-sectional view taken along the line AA shown in FIG. 19A. It is sectional drawing. 21A is a plan view of the scattering member 257, FIG. 21B is a front view, and FIG. 21C is a bottom view. FIG. 22 is a view for explaining the characteristics of the scattering member 257. In FIG. 22, the light flux controlling member main body is omitted.

  As shown in FIGS. 19 to 21, the light flux controlling member 250 includes an incident surface 151, a first total reflection surface 152, two light guides 153, two second total reflection surfaces 154, and two It has an emission surface 155, leg portions 156, and scattering members 257.

  The scattering member 257 is a separate member from the light flux controlling member main body including the incident surface 151, the first total reflection surface 152, the light guide unit 153, the second total reflection surface 154, and the output surface 155. The scattering member 257 mainly transmits light that is transmitted without being reflected by the first total reflection surface 152 while diffusing it. The cross-sectional shape of the scattering member 257 according to Embodiment 2 is a bell-like shape (inverted U-shape). That is, in the cross section parallel to the second direction D2, a part of the inner surface of the scattering member 257 is substantially semicircular. On the inner surface of the scattering member 257, a plurality of prism rows 163 having a substantially semicircular cross-sectional shape are arranged. An engaging protrusion 164 that engages with the guide engaging groove 162 is disposed at the end of the scattering member 257 on the light emitting element 131 side. On the other hand, the outer surface of the scattering member 257 has a predetermined shape to be described later.

  Here, with reference to FIG. 22, the characteristics of the scattering member 257 of the light flux controlling member 250 according to Embodiment 2 will be described. Here, as shown in FIG. 22, a cross section in which the scattering member 257 is cut along a third virtual plane that includes the optical axis OA and is perpendicular to the first virtual line is considered. Assume that there is a point A that can move in the second direction on the surface of the light diffusing plate 140 on the light emitting element 131 side. A point where the optical axis OA of the light emitting element 131 and the surface of the light diffusing plate 140 on the light emitting element 131 side are defined as an intersection point P. The midpoint Q is the midpoint between two adjacent light emitting device rows 130L on the surface of the light diffusing plate 140 on the light emitting element 131 side. Further, a straight line connecting the light emission center of the light emitting element 131 and the point A is defined as a fourth virtual straight line. In the following description, a small angle among the angles formed by the optical axis OA and a virtual straight line connecting the light emission center of the light emitting element 131 and the intermediate point Q is also referred to as a “midpoint angle”.

  When the point A is moved from the intersection point P to the intermediate point Q, the thickness of the scattering member 257 on the fourth virtual straight line is formed so that the point A increases from the intersection point P toward the intermediate point Q. In the present embodiment, the scattering member 257 is formed to have the largest thickness on the fourth imaginary straight line when the point A is located on the intermediate point Q. That is, the thickness of the scattering member 257 on the fourth virtual line after the point A passes the intermediate point Q is the scattering member 257 on the fourth virtual line when the point A is located on the intermediate point Q. Same as or thinner than In the following description, the smaller angle among the angles formed by the optical axis OA and the fourth virtual line when the thickness of the scattering member 257 is the largest on the fourth virtual line is also referred to as the “maximum thickness angle”. . For example, the scattering member 257 satisfying such a shape is formed such that the curvature of the outer surface of the scattering member 257 is smaller than the curvature of the inner side of the scattering member 257 in the cross section cut along the third virtual plane. For example, when the curvature inside the scattering member 257 in the cross section is 1, the curvature of the outer surface of the scattering member 257 in the cross section is 0.5 times. Moreover, if the thickness of the scattering member 257 on the fourth virtual straight line satisfies the above-described condition, the inner surface and the outer surface when the scattering member 257 is cut along the third virtual plane may not be an arc. For example, the inner surface of the scattering member 257 may be an arc and the outer surface may be a plurality of straight lines.

  In the first embodiment, when the point A is moved from the intersection point P to the intermediate point Q, the thickness of the scattering member 157 on the fourth virtual straight line L is formed to be constant (see FIG. 5A). ).

(simulation)
Next, a simulation was performed on the arrival position on the light diffusion plate 140 of the light emitted from the light emitting element 131 arranged in the center of the light emitting element array 131L.

  In this simulation, an apparatus in which the scattering member 257 is assembled to the substrate 120 on which the three light emitting elements 131 are fixed is used. That is, in this simulation, the light flux controlling member main body was not used, and only the effect of the scattering member 257 was examined. The distance between the substrate 120 and the light diffusing plate 140 was 12 mm. Further, among the three light emitting elements 131, only one light emitting element 131 arranged in the central portion was turned on. The optical path in this simulation is symmetric with respect to the center axis CA in FIG. 19A in the horizontal direction (long axis direction) and the vertical direction (short axis direction) in FIG. 19A. On the other hand, the arrival position of the light emitted in the upper right direction was simulated. In addition, simulation was performed on the arrival positions of light emitted at four types of emission angles of 15 °, 20 °, 25 °, and 30 ° with respect to the optical axis OA. For each emission angle, in a cross section cut by a second imaginary plane perpendicular to the optical axis OA, light parallel to the first imaginary line is defined as 0 °, and the angles with respect to the first imaginary line are 0 °, 15 °, 30 A simulation was performed with respect to the arrival positions of seven types of light (°, 45 °, 60 °, 75 °, and 90 ° (28 types in total)). The scattering members used in the simulation were the scattering member 157 of the light flux controlling member 150 according to the first embodiment and the scattering member 257 of the light flux controlling member 250 according to the second embodiment.

  FIGS. 23 and 24 are views showing the arrival positions of the light emitted from the light emitting element 131 at each emission angle and controlled by the scattering members 157 and 257 to the light diffusion plate 140.

  FIG. 23A is a diagram showing the position where the light emitted from the light emitting element 131 with the emission angle of 15 ° and controlled by the scattering members 157 and 257 reaches the light diffusion plate 140, and FIG. It is the figure which showed the arrival position to the light diffusing plate 140 of the light radiate | emitted from the light emitting element 131 with the radiation | emission angle, and was controlled by the scattering members 157 and 257. FIG. FIG. 24A is a view showing the arrival position of the light emitted from the light emitting element 131 with the emission angle of 25 ° and controlled by the scattering members 157 and 257, to the light diffusion plate 140. FIG. FIG. 6 is a view showing the arrival position of light emitted from a light emitting element at an emission angle of 0 ° and controlled by scattering members 157 and 257 to the light diffusion plate 140.

  The horizontal axis and the vertical axis in FIGS. 23 and 24 indicate the distance (mm) in the direction orthogonal to the optical axis OA from the light emitting point (center of the light emitting element 131). Moreover, in FIG. 23 and FIG. 24, the position of the scattering member 257 when viewed in plan is indicated by a dotted line. The black circle symbols in FIGS. 23 and 24 indicate the light arrival position when only the light emitting element 131 is arranged on the substrate 120, and the white triangle symbol is the scattering member 157 according to the first embodiment. The arrival position of the controlled light is shown, and the white square symbol shows the arrival position of the light controlled by the scattering member 257 according to the second embodiment.

  As shown in FIG. 23A and FIG. 23B, the light emitted from the light emitting element 131 at the angles of 15 ° and 20 ° is more emitted when the scattering members 157 and 257 are used than when the scattering member is not used. It can be seen that is controlled to spread in the longitudinal direction of the scattering members 157 and 257 (first direction D1). Further, as shown in FIGS. 24A and 24B, the light emitted from the light emitting element 131 at the angles of 25 ° and 30 ° is obtained when the scattering members 157 and 257 are used rather than when the scattering member is not used. It can be seen that this is controlled not only in the longitudinal direction (first direction D1) but also in the short direction (second direction D2) of the scattering members 157 and 257.

  Next, the luminance distribution in the surface light source device using the light emitting device including the light flux control members 150 and 250 in which the light flux control member main body and the scattering members 157 and 257 are combined was simulated. In this simulation, the luminance distribution on the intersection line with the third virtual plane on the light diffusing plate 140 in the cross section cut at the third virtual plane was obtained. In this simulation, the midpoint angle is 30 °.

  In addition, the light-emitting device used for the simulation used the light-emitting device 130 according to the first embodiment and the light-emitting device according to the second embodiment. For comparison, the light emitting devices A and B that are located between the intersection point P and the intermediate point Q when the position of the scattering member on the fourth virtual straight line is the thickest are also described. Simulated. The light emitting device A is a light emitting device having a scattering member having a maximum thickness angle of 23 °, and the light emitting device B is a light emitting device having a scattering member having a maximum thickness angle of 15 °.

  25A and 25B are graphs showing the luminance distribution on the light diffusing plate 140 on the intersection line with the third virtual plane. 25A shows the luminance distribution in the light-emitting device 130 according to Embodiment 1 and the light-emitting device according to Embodiment 2. FIG. 25B shows the light-emitting device 130, light-emitting device A, and light-emitting device according to Embodiment 1. The luminance distribution in B is shown. The horizontal axes of FIGS. 25A and 25B indicate the angle (°) of an imaginary straight line connecting the light emission center of the light emitting element 131 and the point on the light diffusion plate 140 with respect to the optical axis OA, and the vertical axis indicates the maximum value “1”. ”Indicates the normalized luminance. The broken lines in FIGS. 25A and 25B show the results of the light emitting device 130 according to Embodiment 1, the solid lines in FIG. 25A show the results of the light emitting device according to Embodiment 2, and the dashed line in FIG. Shows the result of the light-emitting device A, and the two-dot chain line in FIG. 25B shows the result of the light-emitting device B.

  As shown in FIG. 25A, it can be seen that in the light emitting device according to the present embodiment in which the midpoint angle and the maximum thickness angle are the same angle (30 °), there is a luminance peak in the vicinity of 30 °. Thus, in the surface light source device in which the light emitting devices are arranged at a constant interval so that the midpoint angle is 30 ° in the second direction D2, each light emitting device is arranged in the second direction D2 from directly above the light emitting element 131. It can be seen that the range up to two intermediate points Q adjacent to can be illuminated uniformly. Although the simulation result is not particularly shown, when three light emitting elements 131 having different colors of emitted light are arranged in the light emitting device and the three light emitting elements 131 are turned on, the light emitted from each light emitting element 131 is emitted. The emitted light is mixed by crossing the optical paths. Accordingly, since the mixed color light reaches the light diffusion plate 140, color unevenness can be suppressed. Therefore, it is suggested that the surface light source device having such a light emitting device has little luminance unevenness between light emitting device rows as a whole and can suppress color unevenness. On the other hand, in the light-emitting devices A and B having the maximum thickness angle smaller than the midpoint angle, the luminance peak angle was less than 30 °. This indicates that in the surface light source device in which the light emitting device is arranged so that the intermediate angle is 30 ° in the second direction D2, luminance unevenness occurs between the light emitting device rows.

(effect)
As described above, in the surface light source device according to the present embodiment, light flux controlling member 250 is formed such that the midpoint angle and the maximum thickness angle are the same angle. Therefore, in addition to the effect according to Embodiment 1, it is possible to further suppress luminance unevenness between the light emitting device columns.

(Modification)
FIG. 26 and FIG. 27 are diagrams showing a configuration of a light flux controlling member 250 ′ according to a modification of the second embodiment. 26A is a plan view of a light flux controlling member 250 ′ according to a modification of the second embodiment, FIG. 26B is a front view, and FIG. 26C is a bottom view. 27A is a right side view of the light flux controlling member 350, FIG. 27B is a sectional view taken along line BB shown in FIG. 26B, and FIG. 27C is a sectional view taken along line AA shown in FIG. 26A. It is sectional drawing.

  As shown in FIGS. 26 and 27, a recess may be formed on the outer surface of the scattering member 257 'of the light flux controlling member 250' according to the modification of the second embodiment. Also in this case, the scattering member 257 ′ is formed such that the maximum thickness angle and the midpoint angle are the same in the cross section cut along the third virtual plane. Although not particularly illustrated, the surface light source device having the light flux controlling member 250 ′ according to the modification of the second embodiment can uniformly illuminate the light diffusing plate 140.

  In the above embodiment, an example in which the light emitting devices 130 are arranged in a rectangular lattice shape has been described. However, the arrangement of the light emitting devices 130 is not limited to this. When viewed along the second direction D2, the light emitting element row 131L includes the first direction included in the light emitting device row 130L adjacent to the light emitting device row 130L including the light emitting device 130 in the second direction D2. It may be arranged between two light emitting element rows 131L adjacent to each other in D1.

  In addition, the arrangement order of the plurality of light emitting elements 131 in the two light emitting devices adjacent in the first direction D1 may be the same or different. When the arrangement order of the plurality of light emitting elements 131 is the same, the arrangement order of the plurality of light emitting elements 131 in the two light emitting devices adjacent in the second direction D2 is different.

  The surface light source device having the light flux controlling member according to the present invention can be applied to, for example, a backlight of a liquid crystal display device, a signboard, or general illumination.

DESCRIPTION OF SYMBOLS 100 Surface light source device 110 Case 120 Board | substrate 130 Light-emitting device 130L Light-emitting device row | line | column 131 Light-emitting element 131L Light-emitting-element row | line | column 140 Light diffusing plate 150,150 ', 150 ", 250,250' Light flux control member 151 Incident surface 152 1st total reflection Surface 153 Light guide portion 154, 154 ′, 154 ″ Second total reflection surface 155 Output surface 156 Leg portion 157, 257, 257 ′ Scattering member 158 Bottom surface 159 First recess 160 Reinforcement member 161 Second recess 162 Guide engagement groove 163 Prism array 164 Engagement protrusion CA Center axis of light flux controlling member OA Optical axis of light emitting element

Claims (9)

A light flux controlling member for controlling the light distribution of the light emitted from the light emitting element,
An incident surface on which light emitted from the light emitting element is incident;
Two directions which are formed at positions facing the light emitting element across the incident surface, and a part of the light incident from the incident surface is substantially perpendicular to the optical axis of the light emitting element and opposite to each other A first total reflection surface to be reflected on
A part of the light incident from the incident surface and the light reflected by the first total reflection surface at positions facing each other across the incident surface and the first total reflection surface are the incident surface and the first total reflection surface. Two light guides each guiding light in a direction away from
Each of the two light guides is disposed at an end, intersects with the optical axis and the optical axis, and a virtual plane including a first virtual straight line along a direction in which the two light guides extend, Two second total reflection surfaces that are incident and reflected at an angle greater than a critical angle so as to be separated from a virtual plane and incident directly on the incident surface;
Two emission surfaces that are formed on the outer surfaces of the two light guides and emit light guided by the light guides to the outside; and
A light flux controlling member.   2. The two second total reflection surfaces each include two inclined surfaces formed so as to approach the virtual plane from the end toward the optical axis in a cross section perpendicular to the optical axis. The light flux controlling member according to 1. A scattering member that controls to scatter light emitted from the first total reflection surface to the outside;
The scattering member is disposed so as to cover at least a part of the first total reflection surface,
A plurality of prism rows are arranged on the inner surface of the scattering member,
The light flux controlling member according to claim 1 or 2. A light emitting element;
The light flux controlling member according to any one of claims 1 to 3, which is disposed so as to intersect the optical axis of the light emitting element.
A light emitting device. A plurality of the light emitting elements are arranged,
The plurality of light emitting elements have different colors of emitted light,
The light emitting device according to claim 4. A plurality of light emitting devices according to claim 5;
A light diffusing plate that diffuses and transmits light emitted from the light emitting device;
Have
The plurality of light emitting devices are arranged as a light emitting device row so that the first imaginary straight line is along a first direction,
The light emitting device rows are arranged in a plurality of rows in a second direction perpendicular to the first direction.
Surface light source device. Each of the plurality of light emitting devices further includes a scattering member that controls to scatter light emitted from the first total reflection surface to the outside,
The scattering member is disposed so as to cover at least a part of the first total reflection surface,
A plurality of prism rows are disposed on the inner surface of the scattering member,
In a cross section cut along a third virtual plane that includes the optical axis and is perpendicular to the first virtual straight line,
The plurality of light emitting device rows are arranged such that the interval between two adjacent light emitting element rows is constant,
The scattering member is
The point A on the surface of the light diffusing plate on the light emitting element side is defined as two adjacent light emitting device rows on the surface of the light diffusing plate on the light emitting element side from the intersection of the optical axis and the light diffusing plate. When moved to the middle point of
As the point A is moved from the intersection point toward the intermediate point, the scattering member is formed so that the thickness of the scattering member on the fourth imaginary straight line connecting the light emission center of the light emitting element and the point A increases. ,
The surface light source device according to claim 6.   The said scattering member is formed so that the thickness of the said scattering member on the said 4th virtual straight line may become the thickest when the said point A is located on the said intermediate point. Surface light source device. A surface light source device according to any one of claims 6 to 8,
A member to be irradiated with light emitted from the surface light source device;
A display device.

Images