JP2022111718A - Luminous flux control member, light emitting device, surface light source device, and display device - Google Patents

Abstract

To provide a light flux control member capable of more uniformly irradiating light emitted from a light emitting element.SOLUTION: A light flux control member includes a plurality of incident units each including an incident surface and a reflective surface, a plurality of output units, and a step surface. When the light flux control member is viewed from above, in the incident unit including a part of the side surface of the light flux control member, a distance between the center of the reflective surface and a first arbitrary point on the edge of the front side of the step surface is longer than a distance between the center of the reflective surface and a second point on the edge of the front side of the side surface of the light flux control member located on the side opposite to the first point with respect to the center of the reflective surface.SELECTED DRAWING: Figure 8

Description

The present invention relates to a light flux controlling member, a light emitting device, a surface light source device and a display device.

2. Description of the Related Art Transmissive image display devices such as liquid crystal display devices sometimes use a direct type surface light source device as the surface light source device. In recent years, a direct type surface light source device having a plurality of light emitting elements as a light source has come to be used (see, for example, Patent Document 1).

Patent Document 1 describes an optical module having a light guide plate, a plurality of light emitting elements arranged in a matrix on one surface of the light guide plate, and a light shielding scattering layer arranged on the other surface of the light guide plate. It is The light guide plate has a first main surface that serves as a light emitting surface and a second main surface that serves as an incident surface. The first main surface has a concave portion including an inclined surface and a flat portion. A light-shielding/scattering layer is arranged so as to cover the concave portion.

Light emitted from the light emitting element enters the light guide plate through the second main surface, is emitted outside through the first main surface, and is reflected sideways. Light emitted from the first main surface is diffused by the light shielding/scattering layer.

U.S. Patent Application Publication No. 2020/0176650

However, in the optical module described in Patent Literature 1, there is room for further study on uniform emission of light emitted from the light emitting element.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a light flux controlling member capable of more uniformly irradiating light emitted from a light emitting element. 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 an embodiment of the present invention is a light flux controlling member for controlling light distribution of light emitted from a plurality of light emitting elements arranged on a substrate, the light flux controlling member comprising: a plurality of incident units for making each emitted light incident thereon; and a plurality of incident units disposed between the plurality of incident units in a lateral direction along the surface of the substrate and guiding the incident light from the plurality of incident units. and a plurality of output units arranged on the front side of the light flux controlling member between the input unit and the output unit such that the front surface of the input unit is higher than the front surface of the output unit. and a stepped surface, wherein the incident unit is arranged on the back side of the light flux controlling member, and is arranged to receive light emitted from the corresponding light emitting element, and the incident surface sandwiches the incident surface. a reflective surface arranged on the front side of the light flux controlling member for reflecting light incident on the incident surface in a lateral direction, and a side surface of the light flux controlling member when the light flux controlling member is viewed in a plan view; , the distance between the center of the reflecting surface and any first point on the edge of the front side of the stepped surface is on the opposite side of the first point with respect to the center of the reflecting surface It is longer than the distance between the center of the reflective surface and the second point on the edge of the front side of the side surface of the light flux controlling member that is positioned.

A light-emitting device according to one embodiment of the present invention includes a plurality of light-emitting elements arranged on a substrate, and the light flux controlling member of the present invention arranged on the plurality of light-emitting elements.

A surface light source device according to an embodiment of the present invention includes a plurality of light emitting devices according to the present invention, and a light diffusion plate that diffuses and transmits light emitted from the plurality of light emitting devices.

A display device according to an embodiment of the present invention includes the surface light source device of the present invention and a display member irradiated with light emitted from the surface light source device.

According to the present invention, it is possible to more uniformly irradiate the light emitted from the light emitting element.

1A and 1B are diagrams showing the configuration of a surface light source device according to Embodiment 1 of the present invention. 2A and 2B are other diagrams showing the configuration of the surface light source device according to Embodiment 1 of the present invention. FIG. 3 is a partially enlarged sectional view of the surface light source device. FIG. 4 is a perspective view showing the configuration of the light flux controlling member according to Embodiment 1 of the present invention. 5A and 5B are diagrams showing the configuration of the light flux controlling member according to Embodiment 1 of the present invention. 6A and 6B are diagrams showing the configuration of the light flux controlling member according to Embodiment 1 of the present invention. 7A and 7B are diagrams for explaining the relationship between the distance between the optical axis of the light emitting element and the second stepped surface and the luminance distribution. FIG. 8 illustrates the relationship between the distance between the center of the reflecting surface and an arbitrary first point on the edge of the front side of the stepped surface, and the relationship between the second point on the edge of the front side on the side surface of the light flux controlling member and the center of the reflecting surface. It is a figure for doing. 9 is a diagram showing a configuration of a light flux controlling member according to Embodiment 2. FIG. 10A to 10F are optical path diagrams of the light emitting device according to Embodiment 1 of the present invention. 11A to 11C are optical path diagrams of the light emitting device according to Embodiment 2. FIG. 12 shows the luminance distribution of the light emitting device according to Embodiment 2. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, as a representative example of the surface light source device according to the present invention, a surface light source device suitable for a backlight of a liquid crystal display device or the like will be described. These surface light source devices can be used as a display device 100' by combining with a display member 102 (for example, a liquid crystal panel) that is irradiated with light from the surface light source device (see FIG. 1B).

[Embodiment 1]
(Configuration of Surface Light Source Device and Light Emitting Device)
1A, B, 2A, B and 3 are diagrams showing the configuration of a surface light source device 100 according to Embodiment 1 of the present invention. FIG. 1A is a plan view of surface light source device 100 according to Embodiment 1 of the present invention, and FIG. 1B is a front view. 2A is a cross-sectional view taken along line AA shown in FIG. 1B, and FIG. 2B is a partially enlarged view of FIG. 2A. FIG. 3 is a partially enlarged view of a cross-sectional view along line BB shown in FIG. 1A.

As shown in FIGS. 1A, B, 2A, B, and 3, the surface light source device 100 according to the embodiment has a housing 110, a plurality of light emitting devices 120, and a light diffusion plate . A plurality of light emitting devices 120 are arranged in a matrix on the bottom plate 112 of the housing 110 . The inner surface of the bottom plate 112 functions as a diffuse reflection surface. Further, the top plate 114 of the housing 110 is provided with an opening. The light diffusing plate 130 is arranged so as to block this opening and functions as a light emitting surface. Although the size of the light emitting surface is not particularly limited, it is, for example, about 400 mm×about 700 mm.

As shown in FIG. 3 , light emitting device 120 has substrate 140 , a plurality of light emitting elements 150 and light flux controlling member 160 . Light flux controlling member 160 is fixed on substrate 140 . The substrate 140 is fixed at a predetermined position on the bottom plate 112 of the housing 110 .

The light emitting element 150 is the light source of the surface light source device 100 and is mounted on the substrate 140 . The light emitting element 150 is, for example, a light emitting diode (LED) such as a white light emitting diode. Also, the type of the light emitting element 150 is not particularly limited. The light-emitting element 150 is preferably a light-emitting element 150 (for example, a COB type light-emitting diode) that emits light from the top and side surfaces. In this embodiment, a light-emitting element 150 having a light-emitting surface smaller than that of a conventional light-emitting element is used. The length of one side of the light emitting surface is, for example, within the range of 0.1 to 1.0 mm.

As shown in FIGS. 2A and 2B, in the present embodiment, a plurality of light emitting elements 150 and a plurality of light flux controlling members 160 are arranged in a grid pattern and spaced apart from each other. Interval L1 between adjacent light flux controlling members 160 may be smaller than half of center-to-center distance L2 between light emitting elements 150 . Here, “the center-to-center distance L2 between the plurality of light-emitting elements 150” means the center-to-center distance between two light-emitting elements 150 belonging to different light-emitting devices 120. FIG. By doing so, the light is guided more widely by light flux controlling member 160 , and darkening between light emitting devices 120 can be suppressed.

It is also important that there is a gap between adjacent light flux controlling members 160 and light flux controlling members 160 are arranged so as not to contact each other. Unless they are arranged with a gap, the light emitted from the edge enters the edge of the adjacent light flux controlling member 160 or is reflected at the edge, which adversely affects the light emission quality on the light diffusion plate 130 . end up

Light flux controlling member 160 is an optical member that controls the light distribution of light emitted from light emitting element 150 . Light flux controlling member 160 is fixed on substrate 140 . As will be described later, light flux controlling member 160 has a plurality of incident units 161 , and light flux controlling member 160 is configured so that the axis of each incident unit 161 and each emitting unit 162 coincides with optical axis LA of each light emitting element 150 . It is arranged on the plurality of light-emitting elements 150 so as to do so. In light flux controlling member 160 according to the present embodiment, incident unit 161 (first incident surface 171 and first reflecting surface 172) of light flux controlling member 160 is rotationally symmetrical (circularly symmetrical). The rotation axis of the incident unit 161 is referred to as "the first axis A1 of the first incident surface 171 or the second axis A2 of the first reflecting surface 172". Also, the “optical axis LA of the light emitting element 150 ” means the center ray of the three-dimensional light flux emitted from the light emitting element 150 . Between substrate 140 on which light emitting element 150 is mounted and the back surface of light flux controlling member 160, a gap is formed to release heat generated from light emitting element 150 to the outside.

Light flux controlling member 160 is formed by integral molding. The material of light flux controlling member 160 is not particularly limited as long as it is a material that allows light of a desired wavelength to pass through. For example, light flux controlling member 160 is made of a light transmissive resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), epoxy resin (EP), or glass.

The light diffusing plate 130 is a plate-shaped member having light diffusing properties, and diffuses and transmits the light emitted from the plurality of light emitting devices 120 . Normally, the light diffusion plate 130 has approximately the same size as a display member such as a liquid crystal panel. For example, the light diffusion plate 130 is made 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 diffusing properties, the surface of the light diffusion plate 130 is formed with fine unevenness, or light diffusers such as beads are dispersed inside the light diffusion plate 130 .

In surface light source device 100 according to the present embodiment, light emitted from each light emitting element 150 is spread by light flux controlling member 160 so as to illuminate a wide range of light diffusion plate 130 . Light emitted from each light flux controlling member 160 is further diffused by light diffusion plate 130 . As a result, the surface light source device 100 according to this embodiment can uniformly illuminate a planar display member (for example, a liquid crystal panel).

(Structure of light flux controlling member)
4, 5A, B and 6A, B are diagrams showing the configuration of light flux controlling member 160. FIG. FIG. 4 is a perspective view of light flux controlling member 160 according to the first embodiment. 5A is a plan view of light flux controlling member 160 according to Embodiment 1, and FIG. 5B is a bottom view thereof. 6A is a side view of light flux controlling member 160 according to Embodiment 1, and FIG. 6B is a cross-sectional view taken along line AA shown in FIG. 5A.

As shown in FIGS. 4, 5A, B and 6A, B, light flux controlling member 160 has a plurality of incident units 161, a plurality of exiting units 162, and a stepped surface 163. FIG. Although not shown, light flux controlling member 160 according to the present embodiment further has supporting legs.

A plurality of incident units 161 are arranged in a lattice corresponding to the arrangement of the light emitting elements 150 . The plurality of emission units 162 are arranged between the plurality of incidence units 161 in the lateral direction along the surface of the substrate 140 . Light flux controlling member 160 includes a plurality of It is arranged on the light emitting element 150 . In this embodiment, the plurality of incident units 161 are arranged at positions corresponding to the four corners of the virtual square. The plurality of emission units 162 includes four first emission units 164 arranged at positions corresponding to four sides of the virtual quadrangle, and one second emission unit 165 arranged at a position surrounded by the virtual quadrangle. . Further, in the present embodiment, the plan view shape of light flux controlling member 160 is a square with four chamfered corners.

A plurality of incident units 161 each receive the light emitted from the light emitting element 150 and emit a part of the light. The multiple incident units 161 each have a first incident surface 171 , a first reflecting surface 172 , and a first side surface 173 .

First incident surface 171 is arranged on the back side of light flux controlling member 160 so as to face light emitting element 150 . First incident surface 171 functions as an incident surface that causes light emitted from light emitting element 150 to enter light flux controlling member 160 . The shape of the first incident surface 171 is not particularly limited as long as it can exhibit the functions described above. In the present embodiment, first incident surface 171 is the inner surface of a recess formed on the back side of light flux controlling member 160 . The shape of the first incident surface 171 intersects the optical axis LA of the light emitting element 150 and is rotationally symmetrical (circularly symmetrical) with respect to the first axis A1 of the first incident surface 171 . Also, the generatrix extending from the central portion to the outer peripheral portion of this rotationally symmetrical plane is a convex curve with respect to the light emitting element 150 . The first incident surface 171 is a curved surface obtained by rotating the generatrix by 360° about the first axis A1. That is, the first incident surface 171 has an aspherical curved surface whose height from the light emitting element 150 decreases as the distance from the first axis A1 increases. The inclination angle of the first incident surface 171 with respect to the first axis A1 increases from the central portion toward the outer peripheral portion.

The first reflecting surface 172 is arranged on the side opposite to the first incident surface 171 . The first reflecting surface 172 functions as an optical surface for reflecting the light incident on the first incident surface 171 in the lateral direction. The shape of the first reflecting surface 172 is not particularly limited as long as it can exhibit the functions described above. In the present embodiment, first reflecting surface 172 is the inner surface of a recess formed on the front side of light flux controlling member 160 . The first reflecting surface 172 intersects the optical axis LA of the light emitting element 150 and is a rotationally symmetrical (circularly symmetrical) surface about the second axis A2 of the first reflecting surface 172 . Also, the generatrix extending from the central portion to the outer peripheral portion of this rotationally symmetrical plane is a concave curve with respect to the light emitting element 150 . The first reflecting surface 172 is a curved surface obtained by rotating the generatrix by 360° around the second axis A2. In addition, the outer peripheral portion of the first reflecting surface 172 is arranged and formed on the front side of the portion of the first reflecting surface 172 that intersects the second axis A2. For example, the first reflecting surface 172 is an aspheric curved surface whose height from the light emitting element 150 increases from the central portion toward the outer peripheral portion. The inclination angle of the first reflecting surface 172 with respect to the plane direction of the substrate 140 decreases from the central portion toward the outer peripheral portion.

First side surface 173 is arranged outside light flux controlling member 160 with respect to first incident surface 171 and first reflecting surface 172 . First side surface 173 is part of the side surface of light flux controlling member 160 . In the present embodiment, when light flux controlling member 160 is viewed from above, first side surface 173 has an arcuate portion 173a and a straight portion 173b connected to the arcuate surface.

Step surface 163 is arranged on the front side of light flux controlling member 160 . A step surface 163 connects the incident unit 161 and the output unit 162 . Stepped surface 163 is a surface arranged between incidence unit 161 and emission unit 162 on the front side of light flux controlling member 160 so that the front side surface of incidence unit 161 is higher than the front side surface of emission unit 162 . be. The shape of the step surface 163 is not particularly limited. However, examples of the shape of the step surface 163 include a flat surface and a curved surface. In the present embodiment, the stepped surface 163 consists of a first stepped surface 163a which is a part of the inner surface of the recess in which the first optical control unit 176 is arranged, and a recess in which the second optical control unit 179 described later is arranged. and a second stepped surface 163b that is part of the side surface. In this embodiment, the first step surface 163a is a flat surface. Further, in the present embodiment, the second stepped surface 163b has an arc shape in plan view, and the cross-sectional shape including the optical axis LA of the light emitting element 150 is also an arc shape.

Stepped surface 163 emits a portion of the light that is incident on first incident surface 171 and reflected by first reflecting surface 172 to the outside of light flux controlling member 160 . The first light flux control section 176 and the emission unit 162 having the second light flux control section 179 are at different distances from the light emitting element 150 . As a result, the optical paths of the light to be emitted are different, so the first stepped surface 163a and the second stepped surface 163b preferably have different shapes as shown in this embodiment.

As described above, the multiple emission units 162 have four first emission units 164 and one second emission unit 165 .

The first output unit 164 has a beam direction changing portion 175 , a first optical control portion 176 and a second side surface 177 .

Light beam direction changing portion 175 is arranged on the back side of light flux controlling member 160 . The light beam direction changing unit 175 changes the traveling direction of the arriving light. The shape of the light beam direction changing portion 175 is not particularly limited as long as the above functions can be exhibited. In the present embodiment, the shape of light beam direction changing portion 175 is the inner surface of a concave portion having a rectangular (rectangular) planar shape formed on the back side of light flux controlling member 160 . In this embodiment, the light beam direction changing portion 175 is formed of four planes. More specifically, light beam direction changing portion 175 includes two first changing surfaces 175a arranged at positions corresponding to the short sides of the rectangle, and two first changing surfaces 175a arranged at positions corresponding to the long sides of the rectangle, and light flux controlling member 160 and a third changing surface 175c located on the outer edge side of light flux controlling member 160 at a position corresponding to the long side of the rectangle. The outer shape of the first changing surface 175a is triangular, and the outer shapes of the second changing surface 175b and the third changing surface 175c are trapezoidal.

First optical controller 176 is arranged on the front side of light flux controlling member 160 . First optical control unit 176 causes the light that has been emitted from light emitting element 150 to enter again, and emits the light that has traveled inside light flux controlling member 160 to the outside. The shape of the first optical control section 176 is not particularly limited as long as the above functions can be exhibited. In the present embodiment, first optical control portion 176 is a part of the inner surface of a concave portion having a rectangular (rectangular) planar shape formed on the front side of light flux controlling member 160 . The first optical control section 176 has two inclined surfaces 176a and one connecting surface 176b.

Inclined surface 176a causes part of the light emitted from first stepped surface 163a to enter light flux controlling member 160 again. Inclined surface 176 a is arranged in the lateral direction along the surface on the front side of light flux controlling member 160 so as to face the front of light flux controlling member 160 as it moves away from incident unit 161 . Connection surface 176 b is a surface that connects two inclined surfaces 176 a and is parallel to the surface on the front side of light flux controlling member 160 .

Second side surface 177 is arranged outside light flux controlling member 160 with respect to light beam direction changing portion 175 and first optical control portion 176 . Second side surface 177 is part of the side surface of light flux controlling member 160 . In the present embodiment, second side surface 177 is part of the side surface of light flux controlling member 160 corresponding to the sides of the virtual square when light flux controlling member 160 is viewed from above, and is formed linearly. In addition, second side surface 177 is arranged so as to be aligned with linear portion 173b of first side surface 173 when light flux controlling member 160 is viewed from above.

The second emission unit 165 has a second reflecting surface 178 and a second optical control section 179 .

Second reflecting surface 178 is arranged on the back side of light flux controlling member 160 . The second reflecting surface 178 reflects the light internally reflected by the first reflecting surface 172 . In the present embodiment, second reflecting surface 178 is connected to the back surface of light flux controlling member 160 and is formed to be flush with the back surface.

Second optical controller 179 is arranged on the front side of light flux controlling member 160 . Second optical control unit 179 causes the light emitted from second stepped surface 163b to enter again, or emits the light traveling inside light flux controlling member 160 to the outside. The shape of the second optical control section 179 is not particularly limited as long as it can exhibit the functions described above. In the present embodiment, second optical control portion 179 is part of the inner surface of a recess formed on the front side of light flux controlling member 160 . The planar view shape of the recess is not particularly limited. In the present embodiment, the shape of the recess in plan view is a substantially square shape with four corners cut toward the center.

The second optical control section 179 has a bottom surface 179a. Bottom surface 179a is the bottom surface of the recess, and causes the light emitted from second stepped surface 163b to enter light flux controlling member 160 again, and causes the light that has traveled inside light flux controlling member 160 to be emitted to the outside.

Here, the relationship between the distance between the optical axis LA of the light emitting element 150 and the second step surface 163b and the luminance distribution will be described. 7A and 7B are diagrams for explaining the relationship between the distance between the optical axis LA of the light emitting element 150 and the second step surface 163b and the luminance distribution. 7A is a plan view of light flux controlling member 160 in which the distance between optical axis LA of light emitting element 150 and second stepped surface 163b is different, and FIG. shows the luminance distribution of light flux controlling member 160 with different values. Note that the configuration of the emission unit 162 is omitted in FIG. 7A. A solid line and a dashed line in FIG. 7A respectively indicate the second step surface 163b. The solid line in FIG. 7B shows the result of the light emitting device 120 using the light flux controlling member 160 having the second step surface 163b that is close to the optical axis LA of the light emitting element 150, and the broken line shows the optical axis LA of the light emitting element 150. 10 shows the result of light emitting device 120 using light flux controlling member 160 having second stepped surface 163b far from .

As described above, in this embodiment, the optical axis LA of the light emitting element 150, the first axis A1 of the first incident surface 171, and the second axis A2 of the first reflecting surface 172 are aligned. As shown in FIGS. 7A and 7B, the second stepped surface 163b is far from the optical axis LA of the light emitting element 150 (the first axis A1 of the first incident surface 171 and the second axis A2 of the first reflecting surface 172). Light-emitting device 120 using light flux controlling member 160 having a second It was found that the luminance at the central portion of light flux controlling member 160 (light emitting device 120) is higher than that of light emitting device 120 using light flux controlling member 160 having two-step surface 163b.

Next, the relationship between the first reflecting surface 172, the stepped surface 163 (first stepped surface 163a and second stepped surface 163b), and the first side surface 173 (arc portion 173a and linear portion 173b) will be described. FIG. 8 is a diagram for explaining the relationship between the first reflecting surface 172, the stepped surface 163, and the first side surface 173. FIG. As shown in FIG. 8 , when light flux controlling member 160 is viewed from above, incidence unit 161 including part of the side surface of light flux controlling member 160 has a center (second axis A2) of first reflecting surface 172 and a step. The distance La between the edge of the front side of surface 163 and arbitrary first point P1 is the distance between light flux controlling member 160 located on the opposite side of first point P1 with respect to the center of first reflecting surface 172 (second axis A2). It is longer than the interval Lb between the second point P2 on the front edge of the first side surface 173 and the center (second axis A2) of the first reflecting surface 172 . Accordingly, part of the light emitted from the light emitting element 150 is emitted from the second side surface 177 . Here, when light flux controlling member 160 is viewed from above, the above relationship is the same even if first side surface 173 is arc-shaped portion 173a, and is the same even if first side surface 173 is linear portion 173b.

(effect)
As described above, in the present invention, the distance between the center of the first reflecting surface 172 (second axis A2) and the step surface 163 is the same as the center of the first reflecting surface 172 (second axis A2) and the first side surface 173 Since it is longer than the interval between the two, the light emitted from light emitting element 150 is bright at the position corresponding to the central portion of light flux controlling member 160 .

[Embodiment 2]
Next, a surface light source device according to Embodiment 2 will be described. Since the surface light source device according to Embodiment 2 differs from surface light source device 100 according to Embodiment 1 only in light flux controlling member 260, only the configuration of light flux controlling member 260 will be mainly described here. The same reference numerals are given to the same configurations as those of light flux controlling member 160 in Embodiment 1, and description thereof will be omitted.

(Structure of light flux controlling member)
9 is a diagram showing a configuration of a light flux controlling member according to Embodiment 2. FIG.

As shown in FIG. 9 , light flux controlling member 260 has multiple incident units 161 and multiple outgoing units 262 . The emission unit 262 has four first emission units 264 and one second emission unit 165 .

The first output unit 264 has a light beam direction changing section 175 (see FIG. 5), a second optical control section 179 and a second side surface 277 . The second side surface 277 is arranged between the two first side surfaces 173 (straight line portions 173b). In the present embodiment, second side surface 277 is linear when light flux controlling member 260 is viewed from above. In addition, two incident units 161 adjacent to each other including a portion of a side surface (first side surface 173) and an emission unit including a portion of a side surface (second side surface 277) disposed between the two incident units 161 In the unit 264, a part of the side surface (second side surface 277) of the first emission unit 264 is a part of the side surface (linear part 173b of the first side surface 173) located on the same plane of the two incident units 161. It is arranged closer to the center of light flux controlling member 260 than the connecting straight line.

(Optical path diagram)
Here, the optical path in the light emitting device 120 according to Embodiment 1 of the present invention and the optical path in the light emitting device according to Embodiment 2 of the present invention are compared.

10A to 10F are optical path diagrams in light emitting device 120 according to Embodiment 1 of the present invention. As described above, light flux controlling member 160 according to Embodiment 1 has four incidence units 161 . The optical paths of light emitted from each light emitting element 150 and incident from the four incident units 161 are the same. Here, only the light emitted from the lower right light emitting element 150 in the light emitting device 120 shown in FIGS. 10A to 10F will be described. More specifically, when the light emitting device 120 is viewed in plan, the light emitted from the lower right light emitting element 150 and directed to the upper right light emitting element 150 is assumed to be 0 degrees, and is changed clockwise (in the plane direction) by 10 degrees. (0 degrees, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees). In addition, when the light emitting device 120 is viewed from the side, the light emitted from the lower right light emitting element 150 and directed to the upper right light emitting element 150 is set to 0 degrees, and is changed counterclockwise (in the height direction) by 10 degrees ( 0 degrees, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees).

FIG. 10A shows the results when the angle in the plane direction is 0 degrees and the angle in the height direction is 0 to 90 degrees, and FIG. 10B shows the results when the angle in the plane direction is 10 degrees and the angle in the height direction is 0 to 90 degrees, FIG. 10C shows the results when the angle in the plane direction is 20 degrees, and the angle in the height direction is 0 to 90 degrees, and FIG. The angle is 30 degrees and the angle in the height direction is 0 to 90 degrees. FIG. 10E shows the results when the angle in the plane direction is 40 degrees and the angle in the height direction is 0 to 90 degrees. , and FIG. 10F shows the results when the plane direction angle is 50 degrees and the height direction angle is 0 to 90 degrees.

11A to 11C are optical path diagrams in a light emitting device according to Embodiment 2 of the present invention. Figures 11A-C correspond to Figures 10D-F, respectively. FIG. 11A shows the results when the angle in the plane direction is 30 degrees and the angle in the height direction is 0 to 90 degrees, and FIG. 11B shows the results when the angle in the plane direction is 40 degrees and the angle in the height direction is 0 to 90 degrees, and FIG. 11C shows the results when the angle in the planar direction is 50 degrees and the angle in the height direction is 0 to 90 degrees.

FIG. 12 shows the luminance distribution of the light emitting device 120 according to the first embodiment and the luminance distribution of the light emitting device according to the second embodiment. A solid line in FIG. 12A indicates the luminance distribution of the light emitting device 120 according to the first embodiment, and a broken line in FIG. 12A indicates the luminance distribution of the light emitting device according to the second embodiment. FIG. 12 also shows the luminance distribution in the cross section taken along the line AA shown in FIG. 10A and the luminance distribution in the cross section taken along the line AA shown in FIG. 11A. The horizontal axis of FIG. 12 indicates the distance from the center of light flux controlling members 160 and 260, and the vertical axis indicates luminance.

As shown in FIGS. 10A to 10F, part of the light emitted from the light emitting element 150 is incident on the first incident surface 171, and the light reflected by the first reflecting surface 172 is reflected by the incident unit 161. It can be seen that the light is also emitted from the second side surface 177 located between the . As a result, the light is emitted from between the incident units 161 (the second side surface 177 of the emitting unit 162) as well, so that the light emitted from the light emitting device 120 is uniformly emitted. In addition, the light beams at angles of 0 degrees, 10 degrees, and 20 degrees in the plane direction are emitted between the incident units 161 (side surfaces of the output unit 162) more than the light beams at angles of 30 degrees, 40 degrees, and 50 degrees in the plane direction. is emitted.

As shown in FIGS. 10D to 10F and FIGS. 11A to 11C, the light with an angle of 30 to 50 degrees in the planar direction in the light emitting device of the present embodiment corresponds to the light with an angle of 30 to 50 degrees in the planar direction in the light emitting device 120 of the first embodiment. It can be seen that more light is emitted outside from the second side surface 277 than the light at 30 to 50 degrees (FIGS. 10D to 10F).

12, in the light-emitting device according to the present embodiment, as compared with the light-emitting device 120 according to the first embodiment, more light is emitted from the second side surface 277. is emitted.

(effect)
As described above, according to the present invention, second side surface 277 is positioned closer to the central portion of light flux controlling member 160 than first side surface 173 . 177 emits a lot of light. Therefore, since the light is emitted also from the area between the two incident units 161, the light can be emitted uniformly without generating a dark portion.

INDUSTRIAL APPLICABILITY The light flux controlling member, the light emitting device and the surface light source device according to the present invention can be applied, for example, to backlights of liquid crystal display devices and general illumination.

REFERENCE SIGNS LIST 100 surface light source device 100' display device 102 display member 110 housing 112 bottom plate 114 top plate 120 light emitting device 130 light diffusion plate 140 substrate 150 light emitting element 160, 260 light flux control member 161 incident unit 162, 262 output unit 163 step surface 163a 1st stepped surface 163b 2nd stepped surface 164, 264 1st output unit 165 2nd output unit 171 1st incident surface 172 1st reflection surface 173 1st side surface 173a Circular portion 173b Linear portion 175 Light ray direction changing portion 175a 1st change Surface 175b Second changing surface 175c Third changing surface 176 First optical control section 176a Inclined surface 176b Connection surface 177, 277 Second side surface 178 Second reflecting surface 179 Second optical control section 179a Bottom surface A1 First axis A2 Second axis L1 Spacing L2 Center distance LA Optical axis P1 First point P2 Second point

Claims (6)

A light flux controlling member for controlling light distribution of light emitted from a plurality of light emitting elements arranged on a substrate,
a plurality of incidence units for respectively injecting the light emitted from the plurality of light emitting elements;
a plurality of emission units arranged between the plurality of incidence units in a lateral direction along the surface of the substrate, and guiding the light incident on the plurality of incidence units to emit the light;
a step surface disposed between the incident unit and the output unit on the front side of the light flux controlling member such that the front surface of the incident unit is higher than the front surface of the output unit;
has
The injection unit is
an incident surface arranged on the back side of the light flux controlling member for allowing the light emitted from the corresponding light emitting element to enter;
a reflecting surface disposed on the front side of the light flux controlling member with the incident surface interposed therebetween, for reflecting light incident on the incident surface in a lateral direction;
has
When the light flux controlling member is viewed in plan, in the incident unit including part of the side surface of the light flux controlling member, the distance between the center of the reflecting surface and an arbitrary first point on the edge of the front side of the stepped surface is , longer than the distance between the center of the reflecting surface and a second point on the edge of the front side of the side surface of the light flux controlling member located on the opposite side of the first point with respect to the center of the reflecting surface;
Luminous flux control member. 2. The light flux controlling member according to claim 1, wherein part of the light that is incident on said incident surface and reflected by said reflecting surface is emitted from said stepped surface to the outside of said light flux controlling member. In the two incident units adjacent to each other and including part of the side surface, and the output unit located between the two incident units and including part of the side surface,
A portion of the side surface of the emission unit is arranged closer to the center of the light flux controlling member than a portion of the side surface of the two incident units located on the same plane,
The light flux controlling member according to claim 1 or 2. a plurality of light emitting elements arranged on a substrate;
a light flux controlling member according to any one of claims 1 to 3, arranged on the plurality of light emitting elements;
A light emitting device. a plurality of light emitting devices according to claim 4;
a light diffusion plate that diffuses and transmits light emitted from the plurality of light emitting devices;
A surface light source device having a surface light source device according to claim 5;
a display member irradiated with light emitted from the surface light source device;
A display device.

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