JP2022165892A - Luminous flux control member, light emitting device, surface light source device and display device - Google Patents

Abstract

To provide a luminous flux control member which can reduce a difference between luminance in a region corresponding to a corner portion of the luminous flux control member and luminance in a region corresponding to a side portion, in a light emitting surface of a surface light source device.SOLUTION: A luminous flux control member includes: a plurality of incident units arranged in a grid-like manner; and a plurality of emission units arranged between the plurality of incident units respectively. The incident unit includes: an incident surface arranged on a rear side of the luminous flux control member; a first reflection surface arranged at the position opposing to a light emitting element by sandwiching the incident surface on a surface side of the luminous flux control member; and a second reflection surface arranged at the position opposing to a side surface of the luminous flux control member by sandwiching the first reflection surface on the surface side of the luminous flux control member.SELECTED DRAWING: Figure 6

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 In recent years, a direct type surface light source device having a plurality of light emitting elements as a light source is used in a transmissive image display device such as a liquid crystal display device. In addition, a large number of light emitting elements may be arranged in order to irradiate light over a wide area.

Patent Document 1 discloses a light flux controlling member (microarray lens) suitable for being arranged on a plurality of light emitting elements. In this microarray lens, a plurality of lenses are connected by a support plate, and one microarray lens is arranged on a plurality of light emitting elements (mini-LEDs) arranged on a substrate. By doing so, there is no need to dispose individual lenses on individual light-emitting elements, which facilitates handling and facilitates mounting.

Chinese Patent Application Publication No. 110208984

In a surface light source device in which a large number of light emitting devices including a plurality of light emitting elements and light flux controlling members disposed thereon are arranged as described above, the present inventors have found that the distance between the light emitting devices is increased so that the light emitting elements I tried to reduce the number of In order to reduce the number of light emitting elements, it is considered necessary to spread the light from the light emitting elements over a wider range by means of a light flux controlling member. In other words, it is considered necessary to prevent light from concentrating locally.

From the above point of view, the present inventors have proposed that, as shown in FIG. We studied the spread of light. Then, as shown in FIG. 1B, in the light emitting surface (light diffusion plate) of the surface light source device, more light is emitted from the side portion 20 than the corner portion 10 and the side portion 20 of the light flux controlling member. It was found that a bright portion was generated in the area corresponding to the portion 20 . Taking the upper right light emitting element 220 in FIG. It is considered that this is because the light is emitted from the

The presence of such a bright portion means that the light is concentrated locally, and if the distance between the light flux controlling members is increased, uneven brightness will occur in the surface light source device. It becomes difficult to increase the distance between

An object of the present invention is to provide a light flux controlling member arranged on a plurality of light emitting elements in a surface light source device, wherein the brightness of the area corresponding to the corner portion of the light flux controlling member on the light emitting surface of the surface light source device and the light flux controlling member It is an object of the present invention to provide a light flux controlling member capable of reducing the difference in luminance between regions corresponding to side portions. Another object of the present invention is to provide a light emitting device, a surface light source device and a display device having this light flux controlling member.

A light flux controlling member 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, wherein the light emitted from the plurality of light emitting elements is a plurality of incidence units arranged in a grid pattern to make the light incident; and a plurality of emission units arranged between the plurality of incidence units to guide the light that has entered the plurality of incidence units to be emitted. , wherein the plurality of incidence units are arranged on the back side of the light flux controlling member, respectively, and have an incidence surface for receiving the light emitted from the light emitting element, and the incidence surface on the front side of the light flux controlling member. a first reflecting surface disposed at a position facing the light emitting element in and reflecting the light incident on the incident surface in a lateral direction along the substrate away from the optical axis of the light emitting element; arranged on the front side of the light flux controlling member at a position facing the side surface of the light flux controlling member with the first reflecting surface interposed therebetween; and a second reflective surface for reflecting light in a lateral direction.

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

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

A display device of the present invention includes the surface light source device described above and a display member irradiated with light emitted from the surface light source device.

According to the present invention, the light flux controlling member can reduce the difference between the brightness of the regions corresponding to the corner portions of the light flux controlling member and the brightness of the regions corresponding to the side portions of the light flux controlling member on the light emitting surface of the surface light source device. can be provided.

Further, according to the present invention, it is possible to provide a light emitting device, a surface light source device, and a display device having the light flux controlling member described above.

1A and 1B are diagrams for explaining the illuminance distribution when a plurality of light emitting elements arranged under the light flux controlling member are turned on. 2A and 2B are diagrams showing the surface light source device according to the embodiment. 3A and 3B are sectional views of the surface light source device according to the embodiment. FIG. 4 is a partially enlarged cross-sectional view of FIG. 3B. 5A to 5E are diagrams showing a light flux controlling member according to Embodiment 1. FIG. 6A and 6B are optical path diagrams of the light emitting device according to Embodiment 1. FIG. 7A shows the illuminance distribution of the surface light source device according to the comparative example, and FIG. 7B shows the illuminance distribution of the surface light source device according to the first embodiment. 8A to 8E are diagrams showing a light flux controlling member according to Modification 1 of Embodiment 1. FIG. 9A to 9C are diagrams showing a light flux controlling member according to Modification 2 of Embodiment 1. FIG. 10A to 10C are diagrams showing a light flux controlling member according to Modification 3 of Embodiment 1. FIG. 11A to 11C are diagrams showing a light flux controlling member according to Modification 4 of Embodiment 1. FIG. 12A to 12C are diagrams showing a light flux controlling member according to Embodiment 2. FIG. 13A to 13C are diagrams showing a light flux controlling member according to Modification 1 of Embodiment 2. FIG. 14A to 14C are diagrams showing a light flux controlling member according to Modification 2 of Embodiment 2. FIG.

[Embodiment 1]
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. This surface light source device can be used as a display device 100′ by combining it with a display member 102 (for example, a liquid crystal panel) that is irradiated with light from the surface light source device (see FIG. 2B).

(Configuration of Surface Light Source Device and Light Emitting Device)
2A and 2B are diagrams showing the configuration of a surface light source device 100 according to an embodiment of the invention. 2A is a plan view and FIG. 2B is a front view. 3A is a cross-sectional view taken along line AA shown in FIG. 2B, and FIG. 3B is a cross-sectional view taken along line BB shown in FIG. 2A. FIG. 4 is a partially enlarged sectional view enlarging a part of FIG. 3B.

As shown in FIGS. 2A to 3B, the surface light source device 100 according to this embodiment has a housing 110, a plurality of light emitting devices 200 and a light diffusion plate 120. FIG. A plurality of light-emitting devices 200 are arranged in a grid pattern (matrix pattern) on bottom plate 112 of 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 120 is arranged so as to close 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. 4, light emitting device 200 is fixed on substrate 210 . The board 210 is fixed at a predetermined position on the bottom plate 112 of the housing 110 . Light emitting device 200 has a plurality of light emitting elements 220 and light flux controlling member 300 .

The light emitting element 220 is the light source of the surface light source device 100 and is mounted on the substrate 210 . In the present embodiment, a plurality of light emitting elements 220 are arranged in a lattice (matrix). Further, in the present embodiment, the pitch at which the light emitting elements 220 are arranged between the light emitting devices 200 is longer than the pitch at which the light emitting elements 220 are arranged within the light emitting device 200 . The light emitting element 220 is, for example, a light emitting diode (LED). The type of light emitting element 220 is not particularly limited, but light emitting element 220 (for example, a COB type light emitting diode) that emits light from the top and side surfaces is preferably used in light emitting device 200 according to the present embodiment. be done. The color of the light-emitting element 220 is not particularly limited, but examples include white, blue, and RGB. Although the size of the light emitting element 220 is not particularly limited, it is preferably 0.1 mm to 0.6 mm. Further, it is more preferable that the size of the light emitting element 220 is 0.1 mm to 0.3 mm.

Light flux controlling member 300 is an optical member that controls the light distribution of light emitted from multiple light emitting elements 220 , and is fixed on substrate 210 . In the present embodiment, light flux controlling member 300 controls light distribution of light emitted from four light emitting elements 220 . Light flux controlling member 300 has a plurality of incident units 310 . Each incident unit 310 (incidence surface 320) includes an incident surface 320 for receiving light emitted from the light emitting element 220 and a first light incident surface 320 for reflecting the light incident on the incident surface 320 toward the emission unit 330, as will be described later. It has a reflecting surface 321 and a second reflecting surface 322 that reflects part of the light reflected by the first reflecting surface 321 toward the side surface of the light flux controlling member 300 . In light flux controlling member 300 according to the present embodiment, incident surface 320 and first reflecting surface 321 are rotationally symmetrical. The rotation axis of the incident surface 320 and the first reflecting surface 321 is called "the central axis of the incident unit 310". Also, the “optical axis LA of the light emitting element 220 ” means the center ray of the three-dimensional light flux emitted from the light emitting element 220 . Between substrate 210 on which light emitting element 220 is mounted and the back surface of light flux controlling member 300, a gap may or may not be formed to allow heat emitted from light emitting element 220 to escape to the outside. good too.

A reflective sheet is preferably provided between substrate 210 on which light emitting element 220 is mounted and the back surface of light flux controlling member 300 . As the reflective sheet, it is preferable to use a sheet with little glossiness. Suppressing the occurrence of the specular component (regular reflection component) and diffusely reflecting the light reflects it on the back surface of the optical sheet (member arranged on the light emitting device 200) of the surface light source device 100, which corresponds to the space between the light emitting devices 200. Light rays incident on a location at small angles are increased. When a sheet that converts the light from the light emitting device 200 into a desired color is used as the optical sheet of the surface light source device 100, the angle of incidence of the light beam on the back surface of the conversion sheet is reduced to reduce the incidence of light into the conversion sheet. Incidence is promoted, and an improvement in conversion efficiency in the region corresponding to the space between the light emitting devices 200 can be expected. Low-gloss reflective sheets include those having a measured gloss of 25-50 GU or 1-20% when measured with a glossmeter set at an incident angle of 60°.

Light flux controlling member 300 is formed by integral molding. The material of light flux controlling member 300 is not particularly limited as long as it is a material that allows light of a desired wavelength to pass therethrough. For example, light flux controlling member 300 is made of a light-transmissive resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), epoxy resin (EP), or glass. The configuration of light flux controlling member 300 will be described later.

The light diffusing plate 120 is a plate-shaped member having light diffusing properties, and diffuses and transmits the emitted light from the light emitting device 200 . Normally, the light diffusion plate 120 has approximately the same size as a display member such as a liquid crystal panel. For example, the light diffusion plate 120 is made of a light-transmitting 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 120 is formed with fine irregularities, or light diffusers such as beads are dispersed inside the light diffusion plate 120 .

In surface light source device 100 according to the present embodiment, light emitted from each light emitting element 220 is spread by light flux controlling member 300 so as to illuminate a wide range of light diffusion plate 120 . Light emitted from each light flux controlling member 300 is further diffused by light diffusion plate 120 . 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)
5A is a plan view of light flux controlling member 300 included in light emitting device 200 according to the present embodiment, FIG. 5B is a bottom view of light flux controlling member 300, and FIG. 5C is a perspective view of light flux controlling member 300. 5D is a front view of light flux controlling member 300, and FIG. 5E is a cross-sectional view taken along line EE of FIG. 5A. The configuration of light flux controlling member 300 will be described below.

As shown in FIG. 5A, in the present embodiment, light flux controlling member 300 is a substantially rectangular plate-like member with rounded corners when viewed from above.

As shown in FIGS. 5A to 5E, light flux controlling member 300 according to the present embodiment is light flux controlling member 300 for controlling the orientation of light emitted from a plurality of light emitting elements 220 arranged on substrate 210. and has a plurality of incidence units 310 and a plurality of emission units 330 . A plurality of incident units 310 are arranged in a grid pattern corresponding to the arrangement of the light emitting elements 220 . Here, a grid is a figure generated by the intersection of a group of equally spaced parallel lines. A line connecting the centers of the four nearest incident units 310 among the plurality of incident units 310 preferably forms a quadrangle such as a square, a rectangle, or a parallelogram. That is, the number of incident units 310 is preferably four or more. On the other hand, the plurality of emission units 330 are arranged between the plurality of incidence units 310 in the direction along the substrate 210 .

The plurality of incident units 310 each receive light emitted from the light emitting elements 220 . The incident unit 310 includes an incident surface 320 for receiving light emitted from the light emitting element 220 , a first reflecting surface 321 for reflecting the light incident on the incident surface 320 toward the output unit 330 , and a first reflecting surface 321 . and a second reflecting surface 322 that laterally reflects the reflected light toward the side surface of light flux controlling member 300 .

Incidence surface 320 is the inner surface of a recess formed on the back side of light flux controlling member 300 and facing light emitting element 220 . Incidence surface 320 allows most of the light emitted from light emitting element 220 to enter inside light flux controlling member 300 while controlling the traveling direction of the light. The incident surface 320 intersects the optical axis LA of the light emitting element 220 and is rotationally symmetrical (circularly symmetrical) with respect to the central axis CA. The shape of the incident surface 320 is not particularly limited, and is set so that light incident on the incident surface 320 is directed toward the first reflecting surface 321 and the exit surface 333 . In the present embodiment, incident surface 320 has a shape such that the distance from substrate 210 gradually decreases with distance from optical axis LA of light emitting element 220 (see FIG. 4).

First reflecting surface 321 is arranged on the front side of light flux controlling member 300 at a position facing light emitting element 220 with incident surface 320 interposed therebetween. Reflect laterally. More specifically, the first reflecting surface 321 preferably reflects substantially all of the light emitted from the center of the light emitting surface of the light emitting element 220 . Here, the lateral direction does not mean the outer edge direction of light flux controlling member 300, but means outward in a 360° radial direction around optical axis LA.

By doing so, the first reflecting surface 321 suppresses upward escape of the light incident on the incident surface 320 to prevent a bright portion from occurring directly above the light emitting elements 220, It also prevents the occurrence of dark areas between the light emitting elements 220 by guiding the light to the . The shape of the first reflecting surface 321 is not particularly limited as long as the light incident from the incident surface 320 can be reflected sideways. The first reflecting surface 321 is, for example, rotationally symmetrical (circularly symmetrical) with respect to the central axis CA of the light emitting element 220, and faces the front side (separates from the substrate 210) as the distance from the optical axis LA of the light emitting element 220 increases. is configured to

A generatrix extending from the rotationally symmetric central portion to the outer peripheral portion is a curved line or straight line inclined with respect to the central axis CA. The first reflecting surface 321 is a concave surface with the central axis CA of the incident surface 320 as a rotation axis, and the generatrix thereof being rotated by 360°.

In the present embodiment, the incident surface 320 and the first reflecting surface 321 are the inner surfaces of the recess, respectively. The area of the opening edge of the concave portion forming 321 is preferably 0.5 to 3.0 times. More preferably, it is 1.0 to 2.5 times.

Second reflecting surface 322 is arranged on the front side of light flux controlling member 300 at a position facing the side surface of light flux controlling member 300 with first reflecting surface 321 interposed therebetween. , are reflected in the lateral direction toward the side surface of light flux controlling member 300 .

In the present embodiment, second reflecting surface 322 is the inner surface of a through hole that opens to the front side and the back side of light flux controlling member 300 . When light flux controlling member 300 is viewed from above, this through hole is arranged in the central portion of light flux controlling member 300 . From the viewpoint of efficiently reflecting the light that has reached the second reflecting surface 322 from the first reflecting surface 321, the second reflecting surface 322 is arranged as follows. That is, as shown in FIG. 5A, when light flux controlling member 300 is viewed from above, in a given incident unit 310 (for example, upper right incident unit 310 in FIG. The optical axis LA of the corresponding light emitting element 220 and the center of gravity of a triangle formed by connecting the centers of the incident unit 310 and the two incident units 310 closest to the incident unit 310 among the plurality of incident units 310 are connected. However, the further away from the first straight line (eg, the EE line in FIG. 5A), the more the distance from the second straight line (eg, straight line L in FIG. 5A) that passes through the optical axis of the light emitting element 220 and is perpendicular to the first straight line. arranged to be longer. Therefore, in the horizontal cross section of light flux controlling member 300 (the cross section parallel to substrate 210), second reflecting surface 322 is a curved line or a straight line inclined with respect to the first straight line (eg, line EE in FIG. 5A). . In this embodiment, the first straight line coincides with the diagonal line of the lattice of the incident units 310 arranged in a lattice.

The angle of inclination of second reflecting surface 322 with respect to substrate 210 (the angle of inclination in the longitudinal section of light flux controlling member 300) is not particularly limited, but from the viewpoint of reflecting laterally toward the side surface of light flux controlling member 300, it is 70°. It is preferably in the range of ~110°. In this embodiment, the inclination angle of the second reflecting surface 322 with respect to the substrate 210 is approximately 90°.

With the second reflecting surface 322 configured as described above, part of the light reflected by the first reflecting surface 321 is directed to the side surface of the light flux controlling member 300 by the second reflecting surface 322 in the lateral direction. It is reflected and emitted from the side surface of light flux controlling member 300 . In the present embodiment, most of the light reflected by second reflecting surface 322 is emitted outside from the side surface of emission unit 330 in light flux controlling member 300 (see FIG. 6A).

The plurality of emission units 330 guide and emit the light incident on the plurality of incidence units 310 . In the present embodiment, when four incident units 310 are arranged at each corner of a virtual quadrangle, light flux controlling member 300 is arranged at positions corresponding to four sides of the virtual quadrangle along each side. It has four emission units 330 arranged. Each emitting unit 330 is arranged on the back side of light flux controlling member 300 and has a third reflecting surface 332 that reflects light from first reflecting surface 321 of incident unit 310 . In addition, emission unit 330 is arranged on the front side of light flux controlling member 300 so as to face third reflecting surface 332, and has emission surface 333 that reflects part of the light from incidence unit 310 and emits the other part. have. Further, part of the light guided in emission unit 330 is also emitted to the outside from the side surface of light flux controlling member 300 .

The shape of the output surface 333 is not particularly limited. In the present embodiment, the four emission surfaces 333 arranged at positions corresponding to the four sides of the virtual quadrangle are planes.

(Optical path of light emitting device)
6A and 6B are optical path diagrams of the light emitting device 200. FIG. FIG. 6A shows an optical path diagram when the light emitting device 200 is viewed from above, and FIG. 6B shows an optical path diagram when the light emitting device 200 is viewed from the side.

As shown in FIG. 6A , in light-emitting device 200 according to the present embodiment, part of light emitted from light-emitting element 220 is reflected laterally by first reflecting surface 321 and reflected by second reflecting surface 322 . head to As shown in FIGS. 6A and 6B , the light that reaches second reflecting surface 322 is reflected laterally toward the side surface of light flux controlling member 300 and emitted to the outside from the side surface of light flux controlling member 300 . The light sequentially reflected by first reflecting surface 321 and second reflecting surface 322 in this manner is emitted to the outside of light flux controlling member 300 from the side surface of light flux controlling member 300 . Moreover, the light emitted to the outside of light flux controlling member 300 includes light substantially parallel to the substrate.

(illuminance distribution)
In order to confirm the effect of light flux controlling member 300 according to the present embodiment, the illuminance A distribution simulation was performed.

Simulation results are shown in FIGS. 7A and 7B. FIG. 7A shows the illuminance distribution of a surface light source device according to a comparative example. The surface light source device of FIG. 7A uses a light flux controlling member that does not have the second reflecting surface 322 as shown in FIG. 1A. On the other hand, FIG. 7B shows the illuminance distribution of the surface light source device 100 according to the embodiment. Surface light source device 100 in FIG. 7B uses light flux controlling member 300 having second reflecting surface 322 as shown in FIG. Note that these simulation results show the illuminance distribution on the back surface of the light diffusion plate 120 (the surface on the light emitting device 200 side).

In this simulation, the illuminance distribution is simulated when only four light emitting elements 220 arranged under one light emitting device are lit in each surface light source device. In FIGS. 7A and 7B, the lower graph shows the horizontal illuminance distribution between the upper two light emitting devices and the lower two light emitting devices, and the right graph shows the two light emitting devices arranged on the right. shows the illuminance distribution in the vertical direction along the optical axis of the light emitting element 220 of FIG.

A comparison of FIGS. 7A and 7B reveals the following. In the surface light source device according to the comparative example shown in FIG. 7A, the regions corresponding to the side portions 20 of the light emitting device are excessively bright. On the other hand, the area corresponding to the side portion 20 of the light emitting device 200 shown in FIG. 7B has appropriate brightness. This is because light flux controlling member 300 in FIG. 7B has second reflecting surface 322, and part of the light reflected by first reflecting surface 321 is reflected by the second reflecting surface without going inside light flux controlling member 300. It's for. That is, surface light source device 100 having light flux controlling member 300 according to the present embodiment suppresses local brightening and spreads the light over a wider range.

(effect)
According to light flux controlling member 300 of the present embodiment, on the light emitting surface of surface light source device 100, the brightness of the region corresponding to corner portion 10 of the light flux controlling member and the brightness of the region corresponding to side portion 20 of the light flux controlling member difference can be reduced. Therefore, it is possible to increase the distance between the light emitting devices 200 while suppressing luminance unevenness.

[Modification 1 of Embodiment 1]
(Configuration of Surface Light Source Device, Light Emitting Device, and Light Flux Controlling Member)
The surface light source device according to Modification 1 of Embodiment 1 differs from Embodiment 1 in that, in light flux controlling member 400, second reflecting surface 322 is not the inner surface of the through hole but the inner surface of the bottomed concave portion. It is different from the surface light source device 100 concerned. In the surface light source device according to Modification 1 of Embodiment 1, members similar to those of surface light source device 100 according to Embodiment 1 are denoted by the same reference numerals, and descriptions thereof are omitted.

8A to 8E show light flux controlling member 400 according to Modification 1 of Embodiment 1. FIG. 8A is a plan view of light flux controlling member 400, FIG. 8B is a bottom view of light flux controlling member 400, FIG. 8C is a perspective view of light flux controlling member 400, and FIG. 8D is a front view of light flux controlling member 400. 8E is a cross-sectional view taken along line EE of FIG. 8A.

In light flux controlling member 400 according to Modification 1 of Embodiment 1, second reflecting surface 322 is the inner surface (inner side surface) of a bottomed recess opening on the front side of light flux controlling member 400 . The portion below the recess (the portion between the bottom surface of the recess and the back surface of light flux controlling member 400 ) guides the light from incident unit 310 and emits it, functioning like emission unit 330 . Also in light flux controlling member 400 according to the present embodiment, second reflecting surface 322 has the same function as second reflecting surface 322 of light flux controlling member 300 according to the first embodiment. That is, the light reflected by first reflecting surface 321 and reaching second reflecting surface 322 is reflected by second reflecting surface 322 toward the lateral direction of light flux controlling member 400 , and the light flux is emitted from the side surface of light flux controlling member 400 . The light is emitted to the outside of the control member 400 .

(effect)
Similarly to light flux controlling member 300 according to Embodiment 1, light flux controlling member 400 according to Modification 1 of Embodiment 1 also corresponds to corner portion 10 of the light flux controlling member on the light emitting surface of the surface light source device. The difference between the brightness of the area and the brightness of the area corresponding to the side portion 20 of the light flux controlling member can be reduced. Therefore, it is possible to increase the distance between the light emitting devices 200 while suppressing luminance unevenness.

[Modification 2 of Embodiment 1]
(Configuration of Surface Light Source Device, Light Emitting Device, and Light Flux Controlling Member)
The surface light source device according to Modification 2 of Embodiment 1 is characterized in that, in light flux controlling member 500 , second reflecting surface 322 is not a through hole but the inner surface of a bottomed concave portion, and that the back side of light flux controlling member 300 It is different from surface light source device 100 according to Embodiment 1 in that it has legs 534 arranged. In the surface light source device according to Modification 2 of Embodiment 1, members similar to those of surface light source device 100 according to Embodiment 1 are denoted by the same reference numerals, and descriptions thereof are omitted.

9A to 9C show a light flux controlling member 500 according to Modification 2 of Embodiment 1. FIG. 9A is a plan view of light flux controlling member 500, FIG. 9B is a bottom view of light flux controlling member 500, and FIG. 9C is a sectional view taken along line AA shown in FIG. 9A.

In light flux controlling member 500 according to the present modification, second reflecting surface 322 is the inner surface of a bottomed recess opening on the front side of light flux controlling member 500 . The portion under this recess (the portion between the bottom surface of the recess and the back surface of light flux controlling member 500 ) guides the light from incident unit 310 and emits it, functioning like emission unit 330 . Also in light flux controlling member 500 according to the present modification, second reflecting surface 322 has the same function as second reflecting surface 322 of light flux controlling member 300 according to the first embodiment. That is, the light reflected by first reflecting surface 321 and reaching second reflecting surface 322 is reflected by second reflecting surface 322 toward the lateral direction of light flux controlling member 400 , and the light flux is emitted from the side surface of light flux controlling member 500 . The light is emitted to the outside of the control member 500 .

Light flux controlling member 500 according to the present modification further includes legs 534 in addition to multiple incident units 310 and multiple output units 330 . Leg portion 534 is arranged on the back side of light flux controlling member 500 and is used to fix light flux controlling member 500 to substrate 210 . The shape of the leg portion 534 is not particularly limited as long as it can exhibit the above functions. In this modified example, the leg portion 534 has a cylindrical shape. The number of legs 534 is also not particularly limited. The number of legs 534 may be one, or two or more. In this modification, the number of legs 534 is four. The arrangement of the legs 534 is also not particularly limited. For example, the four legs 534 may be positioned at each corner of a rhombus or may be positioned at each corner of a square. In this modified example, the four legs 534 are arranged so as to be positioned at each corner of the square. Accordingly, light flux controlling member 500 can be fixed to substrate 210 without considering the orientation thereof. Four legs 534 are arranged closer to the center of gravity of light flux controlling member 500 than second reflecting surface 322 when light flux controlling member 500 is viewed from above (planar transparent view).

(effect)
Light flux controlling member 500 according to the present modification, similarly to light flux controlling member 300 according to Embodiment 1, has a brightness and a light flux control in a region corresponding to corner portion 10 of light flux controlling member 500 on the light emitting surface of the surface light source device. It is possible to reduce the difference from the brightness of the area corresponding to the side portion 20 of the member 500 . Therefore, it is possible to increase the distance between the light emitting devices while suppressing luminance unevenness. Further, in the conventional light flux controlling member, when the leg portion is arranged near the center (center of gravity) of the light flux controlling member, a bright portion is likely to occur directly above the center of the light flux controlling member due to the influence of the leg portion. In such light flux controlling member 500 , second reflecting surface 322 reduces the amount of light reaching near the center of gravity of light flux controlling member 500 . It is difficult for a bright part to occur directly above the .

[Modification 3 of Embodiment 1]
(Configuration of Surface Light Source Device, Light Emitting Device, and Light Flux Controlling Member)
Surface light source device according to Modification 3 of Embodiment 1 is characterized in that, in light flux controlling member 600 , second reflecting surface 322 is not a through hole but an inner surface of a recess with a bottom, and that the surface of light flux controlling member 300 has It differs from the surface light source device 100 according to the first embodiment in that it has the protrusions 635 arranged. In the surface light source device according to this modified example, members similar to those of the surface light source device 100 according to Embodiment 1 are denoted by the same reference numerals, and descriptions thereof are omitted.

10A to 10C show a light flux controlling member 600 according to Modification 3 of Embodiment 1. FIG. 10A is a plan view of light flux controlling member 600, FIG. 10B is a bottom view of light flux controlling member 600, and FIG. 10C is a sectional view taken along line AA shown in FIG. 10A.

In light flux controlling member 600 according to the present modification, second reflecting surface 322 is the inner surface of a bottomed recess opening on the front side of light flux controlling member 600 . The portion below the recess (the portion between the bottom surface of the recess and the back surface of light flux controlling member 600 ) guides the light from incident unit 310 and emits it, functioning like emission unit 330 . Also in light flux controlling member 600 according to the present modification, second reflecting surface 322 has the same function as second reflecting surface 322 of light flux controlling member 300 according to the first embodiment. That is, the light reflected by first reflecting surface 321 and reaching second reflecting surface 322 is reflected by second reflecting surface 322 toward the lateral direction of light flux controlling member 600 , and the light flux is emitted from the side surface of light flux controlling member 600 . The light is emitted to the outside of control member 600 .

Light flux controlling member 600 according to the present modification further includes protrusions 635 in addition to multiple incident units 310 and multiple output units 330 .

Protrusions 635 prevent light diffusion plate 120 from contacting surfaces other than protrusions 635 of light flux controlling member 600 when light diffusion plate 120 is bent. Protrusion 635 protrudes from the surface of light flux controlling member 600 toward the front side (light diffusion plate 120 side), and the maximum height of protrusion 635 is the maximum height of the portion of light flux controlling member 600 other than protrusion 635 . higher than The shape of the protrusion 635 is not particularly limited as long as it can exhibit the above functions. Examples of shapes for protrusion 635 include conical, frusto-conical, cylindrical, hemispherical, and combinations thereof. In this modified example, the shape of the protrusion 635 is a shape in which a hemisphere is placed on a cylinder. The number of protrusions 635 is not particularly limited. The number of protrusions 635 may be one, or two or more. In this modification, the number of protrusions 635 is one. In addition, in this modified example, projection 635 is arranged in the central portion of the concave portion (the central portion of light flux controlling member 600) having second reflecting surface 322 as the inner side surface. When there are four protrusions 635, the protrusions 635 may be arranged at equal intervals in the central portion of the recess having the second reflecting surface 322 as the inner side surface.

(effect)
Light flux controlling member 600 according to the present modification, similarly to light flux controlling member 300 according to the first embodiment, has the luminance and luminous flux of the region corresponding to corner portion 10 of light flux controlling member 600 on the light emitting surface of the surface light source device. It is possible to reduce the difference in luminance between the regions corresponding to the side portions 20 of the control member 600 . Therefore, it is possible to increase the distance between the light emitting devices while suppressing luminance unevenness. In addition, since projections 635 are arranged, light diffusion plate 120 can be prevented from coming into contact with surfaces other than projections 635 of light flux controlling member 600 .

[Modification 4 of Embodiment 1]
(Configuration of Surface Light Source Device, Light Emitting Device, and Light Flux Controlling Member)
A surface light source device according to Modification 4 of Embodiment 1 is characterized in that, in light flux controlling member 700 , second reflecting surface 322 is not a through hole but the inner surface of a recess with a bottom, and is arranged on the back side of light flux controlling member 300 . It is different from the surface light source device 100 according to the first embodiment in that it has a raised portion 736 . In the surface light source device according to Modification 3 of Embodiment 1, members similar to those of surface light source device 100 according to Embodiment 1 are denoted by the same reference numerals, and descriptions thereof are omitted.

11A to 11C show a light flux controlling member 700 according to Modification 4 of Embodiment 1. FIG. 11A is a plan view of light flux controlling member 700; FIG. 11B is a bottom view of light flux controlling member 700; and FIG. be.

In light flux controlling member 700 according to the present modification, second reflecting surface 322 is the inner surface of a bottomed recess opening on the front side of light flux controlling member 700 . The portion below the recess (the portion between the bottom surface of the recess and the back surface of light flux controlling member 700 ) guides the light from incident unit 310 and emits it, functioning like emission unit 330 . Also in light flux controlling member 700 according to the present modification, second reflecting surface 322 has the same function as second reflecting surface 322 of light flux controlling member 300 according to the first embodiment. That is, the light reflected by first reflecting surface 321 and reaching second reflecting surface 322 is reflected by second reflecting surface 322 toward the lateral direction of light flux controlling member 700 , and the light flux is emitted from the side surface of light flux controlling member 700 . The light is emitted to the outside of control member 700 .

In light flux controlling member 700 according to the present modification, each of incidence units 310 further has convex portion 736 .

Convex portions 736 are arranged at the four corners on the back side of light flux controlling member 700 corresponding to incident surface 321 of each incident unit 310 . In this modified example, the convex portion 736 has an inverted truncated cone shape, and the concave portion whose inner surface serves as the incident surface 321 opens to the upper surface of the convex portion 736 . Therefore, when light flux controlling member 700 is viewed from above (bottom view), the upper surface of the truncated cone (surface on light emitting element 220 side) is larger than incident surface 321 . The height of the convex portion 736 is not particularly limited as long as the convex portion 736 does not contact the light emitting element 220 . The height of the protrusion 736 is, for example, 0.05 to 1 mm. In this embodiment, the height of the protrusion 736 is 0.25 mm. Further, the distance between the center of incident surface 321 of light flux controlling member 300 and the center of first reflecting surface 321 in Embodiment 1 and the center of incident surface 321 of light flux controlling member 700 in Modification 4 of Embodiment 1 and the distance between the centers of the first reflecting surfaces 321 are the same. In other words, the incident surface 321 in the present embodiment is extended toward the light emitting element 220 from the incident surface 321 in the first embodiment. This allows more light to enter light flux controlling member 700 . Further, the distance between substrate 210 on which light emitting element 220 is mounted and the back surface of light flux controlling member 300 (the portion of the back surface of light flux controlling member 300 where convex portion 736 is not arranged) is the same as in the first embodiment. and Modification 4 of Embodiment 1 are the same. In addition, in the present embodiment, a gap is formed between the light emitting element 220 and the substrate 120 to release the heat generated from the light emitting element 220 to the outside.

(effect)
Light flux controlling member 700 according to the present modification, similarly to light flux controlling member 300 according to Embodiment 1, has a luminance and a light flux control in a region corresponding to corner portion 10 of light flux controlling member 700 on the light emitting surface of the surface light source device. It is possible to reduce the difference from the brightness of the area corresponding to the side portion 20 of the member 700 . Therefore, it is possible to increase the distance between the light emitting devices while suppressing luminance unevenness. In addition, since convex portion 736 is arranged on the back side of light flux controlling member 700 , more of the light emitted from light emitting element 220 can enter light flux controlling member 700 .

[Embodiment 2]
(Configuration of Surface Light Source Device, Light Emitting Device, and Light Flux Controlling Member)
In light flux controlling member 800, the surface light source device according to the second embodiment has the shape of light flux controlling member 800 when viewed from above, and second reflecting surface 322 is not a through hole but an inner surface of a recess with a bottom. , and the leg portion 534 arranged on the back side of the light flux controlling member 800 is different from the surface light source device 100 according to the first embodiment. In the surface light source device according to the second embodiment, members similar to those of the surface light source device 100 according to the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

12A to 12C show a light flux controlling member 800 according to Embodiment 2. FIG. 12A is a plan view of light flux controlling member 800, FIG. 12B is a bottom view of light flux controlling member 800, and FIG. 12C is a sectional view taken along line AA shown in FIG. 12A.

The plan view shape of light flux controlling member 800 according to Embodiment 2 is a shape in which the midpoints of the sides of a quadrangle (square) are moved toward the center. In this embodiment, each corner of the quadrangle is rounded, but the corner formed by extending two adjacent sides (straight lines) is an acute angle.

Second reflecting surface 322 of light flux controlling member 800 according to the present embodiment is the inner surface of a bottomed recess opening on the front side of light flux controlling member 800 . The portion under the recess (the portion between the bottom surface of the recess and the back surface of light flux controlling member 800) guides and emits light from incident unit 310, and functions like emitting unit 330. FIG. Also in light flux controlling member 800 according to the present embodiment, second reflecting surface 322 has the same function as second reflecting surface 322 of light flux controlling member 300 according to the first embodiment. That is, the light reflected by first reflecting surface 321 and reaching second reflecting surface 322 is reflected by second reflecting surface 322 toward the lateral direction of light flux controlling member 800 , and the light flux is emitted from the side surface of light flux controlling member 800 . The light is emitted to the outside of control member 800 .

Light flux controlling member 800 according to the present embodiment further includes legs 534 in addition to multiple incident units 310 and multiple output units 330 . Since the leg portion 534 is the same as the leg portion 534 of Modification 2 of Embodiment 1, description thereof is omitted.

(effect)
In light flux controlling member 800 according to the present embodiment, similarly to light flux controlling member 300 according to the first embodiment, on the light emitting surface of the surface light source device, the luminance and luminous flux of the region corresponding to corner portion 10 of light flux controlling member 800 are adjusted. It is possible to reduce the difference from the brightness of the area corresponding to the side portion 20 of the control member 800 . Therefore, it is possible to increase the distance between the light emitting devices while suppressing luminance unevenness. In addition, in the conventional light flux controlling member, when the leg is arranged near the center (center of gravity) of the light flux controlling member, the influence of the leg tends to cause a bright portion right above the center of the light flux controlling member. In light flux controlling member 800 according to , since less light reaches near the center of gravity of light flux controlling member 800 due to second reflecting surface 322, even if the leg portion is arranged near the center of gravity of light flux controlling member 800, light flux controlling member A bright portion is less likely to occur directly above 800 .

[Modification 1 of Embodiment 2]
(Configuration of Surface Light Source Device, Light Emitting Device, and Light Flux Controlling Member)
In the surface light source device according to Modification 1 of Embodiment 2, light flux controlling member 900 has a shape when light flux controlling member 900 is viewed from above, and second reflecting surface 322 is not a through hole but an inner surface of a concave portion with a bottom. , and in that projection 635 is provided on the front side of light flux controlling member 900, surface light source device 100 differs from surface light source device 100 according to the first embodiment. In the surface light source device according to the present embodiment, members similar to those of the surface light source device 100 according to the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

13A to 13C show a light flux controlling member 900 according to Modification 1 of Embodiment 2. FIG. 13A is a plan view of light flux controlling member 900, FIG. 13B is a bottom view of light flux controlling member 900, and FIG. 13C is a sectional view taken along line AA shown in FIG. 13A.

The plan view shape of light flux controlling member 900 according to this modified example is a shape in which the midpoints of the sides of a quadrangle (square) are moved toward the center. In this modification, each corner of the quadrangle is rounded, but the corner formed by extending two adjacent sides (straight lines) is an acute angle.

In light flux controlling member 900 according to the present modification, second reflecting surface 322 is the inner surface of a bottomed recess opening on the front side of light flux controlling member 900 . The portion below the recess (the portion between the bottom surface of the recess and the back surface of light flux controlling member 900 ) guides the light from incident unit 310 and emits it, functioning like emission unit 330 . Also in light flux controlling member 900 according to the present modification, second reflecting surface 322 has the same function as second reflecting surface 322 of light flux controlling member 300 according to the first embodiment. That is, the light reflected by first reflecting surface 321 and reaching second reflecting surface 322 is reflected by second reflecting surface 322 toward the lateral direction of light flux controlling member 900 , and the light flux is emitted from the side surface of light flux controlling member 900 . The light is emitted to the outside of the control member 900 .

Light flux controlling member 900 according to the present modification further includes protrusions 635 in addition to multiple incident units 310 and multiple output units 330 . Since the protrusion 635 is the same as the protrusion 635 of Modification 3 of Embodiment 1, description thereof will be omitted.

(effect)
In light flux controlling member 900 according to the present modification, similarly to light flux controlling member 300 according to the first embodiment, the brightness of the region corresponding to corner portion 10 of light flux controlling member 900 on the light emitting surface of the surface light source device It is possible to reduce the difference from the brightness of the area corresponding to side portion 20 of light flux controlling member 900 . Therefore, it is possible to increase the distance between the light emitting devices while suppressing luminance unevenness. Moreover, since projections 635 are arranged, light diffusion plate 120 can be prevented from coming into contact with surfaces other than projections 635 of light flux controlling member 900 .

[Modification 2 of Embodiment 2]
(Configuration of Surface Light Source Device, Light Emitting Device, and Light Flux Controlling Member)
In light flux controlling member 1000, a surface light source device according to Modification 2 of Embodiment 2 has a shape when light flux controlling member 1000 is viewed from above, and second reflecting surface 322 is not a through hole but an inner surface of a recess with a bottom. , and the convex portion 736 arranged on the back side of the light flux controlling member 1000 is different from the surface light source device 100 according to the first embodiment. In the surface light source device according to Modification 3 of Embodiment 1, members similar to those of surface light source device 100 according to Embodiment 1 are denoted by the same reference numerals, and descriptions thereof are omitted.

14A to 14C show a light flux controlling member 1000 according to Modification 2 of Embodiment 2. FIG. 14A is a plan view of light flux controlling member 1000, FIG. 14B is a bottom view of light flux controlling member 1000, and FIG. 14C is a sectional view taken along line AA shown in FIG. 14A.

The plan view shape of light flux controlling member 1000 according to this modification is a shape in which the midpoints of the sides of a quadrangle (square) are shifted toward the center. In this modification, each corner of the quadrangle is rounded, but the corner formed by extending two adjacent sides (straight lines) is an acute angle.

In light flux controlling member 1000 according to the present modification, second reflecting surface 322 is the inner surface of a bottomed recess opening on the front side of light flux controlling member 1000 . The portion below the recess (the portion between the bottom surface of the recess and the back surface of light flux controlling member 1000 ) guides the light from incident unit 310 and emits it, functioning like emission unit 330 . Also in light flux controlling member 1000 according to the present modification, second reflecting surface 322 has the same function as second reflecting surface 322 of light flux controlling member 300 according to the first embodiment. That is, the light reflected by first reflecting surface 321 and reaching second reflecting surface 322 is reflected by second reflecting surface 322 toward the lateral direction of light flux controlling member 1000 , and the light flux is emitted from the side surface of light flux controlling member 1000 . The light is emitted to the outside of control member 1000 .

Light flux controlling member 1000 according to the present modification further includes projections 736 in addition to multiple incident units 310 and multiple output units 330 . Since the convex portion 736 is the same as the convex portion 736 of Modification 4 of Embodiment 1, description thereof is omitted.

(effect)
Light flux controlling member 1000 according to the present modification, similarly to light flux controlling member 300 according to Embodiment 1, has a luminance and a light flux control in a region corresponding to corner portion 10 of light flux controlling member 1000 on the light emitting surface of the surface light source device. It is possible to reduce the difference from the brightness of the area corresponding to the side portion 20 of the member 1000 . Therefore, it is possible to increase the distance between the light emitting devices while suppressing luminance unevenness. In addition, since convex portion 736 is arranged on the back side of light flux controlling member 1000 , more of the light emitted from light emitting element 220 can enter light flux controlling member 1000 .

The light-emitting device and surface light source device of the present invention can be applied, for example, to backlights of liquid crystal display devices and general illumination.

10 corner portion 20 side portion 100 surface light source device 100' display device 102 display member 110 housing 112 bottom plate 114 top plate 120 light diffusion plate 200 light emitting device 210 substrate 220 light emitting element 300, 400, 500, 600, 700, 800, 900 , 1000 light flux controlling member 310 incident unit 320 incident surface 321 first reflecting surface 322 second reflecting surface 330 emitting unit 332 third reflecting surface 333 emitting surface 534 leg 635 protrusion 736 protrusion CA central axis LA optical axis

Claims (10)

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 arranged in a grid for allowing the light emitted from the plurality of light emitting elements to enter each;
a plurality of emission units arranged between the plurality of incidence units, and guiding the light incident on the plurality of incidence units to emit the light;
has
each of the plurality of incidence units is arranged on the back side of the light flux controlling member, and has an incidence surface on which the light emitted from the light emitting element is incident;
A light emitting element is arranged on the front side of the light flux controlling member at a position facing the light emitting element with the incident surface interposed therebetween, and directs the light incident on the incident surface along the substrate so as to be away from the optical axis of the light emitting element. a first reflecting surface that reflects in a direction;
It is arranged on the front side of the light flux controlling member at a position facing the side surface of the light flux controlling member with the first reflecting surface interposed therebetween. A second reflecting surface that reflects laterally toward
having
Luminous flux control member. 2. The light flux controlling member according to claim 1, wherein an inclination angle of said second reflecting surface with respect to said substrate is within a range of 70° to 110°. When the light flux controlling member is viewed from above, in each of the plurality of incident units, the second reflecting surface is aligned with the optical axis of the light emitting element corresponding to the incident unit and the incident light of the plurality of incident units. The further away from the first straight line connecting the unit and the center of gravity of the triangle formed by connecting the centers of the two incident units closest to the incident unit, the more it passes through the optical axis of the light emitting element and along the first straight line The light flux controlling member according to claim 1 or 2, arranged so that the distance from the perpendicular second straight line increases. The second reflecting surface according to any one of claims 1 to 3, wherein the second reflecting surface is an inner surface of a recess opening on the front side of the light flux controlling member, or an inner surface of a through hole opening on the front side and back side of the light flux controlling member. A light flux controlling member as described. further comprising a leg arranged on the back side of the light flux controlling member,
When the light flux controlling member is viewed from above, the leg is arranged closer to the center of gravity of the light flux controlling member than the second reflecting surface.
The light flux controlling member according to any one of claims 1 to 4. a plurality of light emitting elements arranged on a substrate;
The light flux controlling member according to any one of claims 1 to 5, arranged on the plurality of light emitting elements;
A light emitting device. 7. The light emitting device according to claim 6, wherein the light sequentially reflected by said first reflecting surface and said second reflecting surface is emitted to the outside of said light flux controlling member from a side surface of said light flux controlling member. 8. The light emitting device according to claim 7, wherein the light emitted to the outside of said light flux controlling member includes light substantially parallel to said substrate. a plurality of light emitting devices according to any one of claims 6 to 8;
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 9;
a display member irradiated with light emitted from the surface light source device;
A display device.

Images