JP6093748B2 - Light flux controlling member, light emitting device, surface light source device, and display device - Google Patents

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 Conventionally, a surface light source device using a plurality of light emitting diodes (LEDs) as point light sources is known as illumination means for a liquid crystal display monitor used in personal computers, televisions, and the like.

  In the surface light source device, a plurality of LEDs are arranged in a matrix on the back side of a plate-shaped light flux controlling member having substantially the same shape as the liquid crystal display panel of the liquid crystal display monitor. The surface light source device causes the light emitted from the LED to enter the inside of the light flux control member, and controls the traveling direction of the light when the light is emitted from the light flux control member. The surface light source device diffuses the light emitted from the light flux controlling member by the light diffusing member, and then illuminates the liquid crystal display panel in a planar shape from the back side.

  Patent Document 1 describes a planar light source in which light transmitted through an optical element is emitted substantially perpendicularly to a plane. FIG. 1 is a diagram schematically showing a surface light source device using an LED described in Patent Document 1 as a light source.

  As shown in FIG. 1, in the surface light source device 100, a microlens array 102 is disposed so as to correspond to each of the plurality of LEDs 101 on a one-to-one basis. When the microlens array 102 controls the traveling direction of the light emitted from the LED 101, the surface light source device 100 emits light in a direction (upward) perpendicular to the substrate plane.

  In Patent Document 2, a hollow portion is formed inside the convex portion of the lens case, and a void portion having an inclined surface that reflects light emitted from the light emitting element in the lateral direction toward the convex portion on the outer periphery from the hollow portion. A formed display device is described.

  FIG. 2 is a configuration diagram showing a display device described in Patent Document 2. As shown in FIG. As shown in FIG. 2, in the matrix display device 130, light emitting elements 132 are arranged in a matrix on the display panel substrate 131, and a lens case 133 is disposed on the surface side of the light emitting elements 132. The lens case 133 is placed in close contact with the display panel substrate 131. In the lens case 133, a substantially hemispherical convex portion 134 is formed at a position corresponding to the light emitting element 132, and a hollow portion 135 that encloses the light emitting element 132 is formed inside the convex portion 134. The side wall of the cavity 135 takes in the light emitted from the light emitting element 132 by being refracted toward the front side (the upper side in FIG. 2). The incident surface of the light emitted from the light emitting element 132 is only the side wall of the cavity portion 135. In the lens case 133, a gap 136 is formed around a cavity 135 that encloses the light emitting element 132. The gap 136 totally reflects light, which is emitted from the light emitting element 132 in the lateral direction and then taken into the lens case 133, toward the front side by the inclined surface 137 and the insulating substrate 138 of the gap 136. Thereby, the illumination light luminance on the front side of the matrix display device 130 is increased.

JP 2002-49326 A JP 2001-250986 A

  However, in such a conventional surface light source device, the light emitted from the light emitting element is incident on the back surface (the surface facing the substrate) of the light flux control member, and the light flux control member collects and emits this light. Therefore, there is a problem that unevenness in illuminance occurs on the irradiated surface. Illuminance unevenness hinders uniform planar illumination and degrades illumination quality.

  This invention is made | formed in view of this point, and it aims at providing the light beam control member, light-emitting device, surface light source device, and display apparatus which can suppress illumination intensity nonuniformity.

The light flux controlling member of the present invention is a light flux controlling member for controlling the traveling direction of the light emitted from the light emitting element, the light control emitting surface for controlling the traveling direction of the light emitted from the light emitting element, and the light control. A grid having a recess located on the opposite side of the exit surface and a back surface extending in a radial direction from an opening edge of the recess, and on the back surface, a plurality of projections of a plurality of filaments are arranged in a grid pattern A grid-like convex part or a grid-like concave part in which concave parts of a plurality of filaments are arranged in a grid pattern, and the convex part of the filaments or the concave part of the filaments is in the extending direction of the filaments. The orthogonal cross-sectional shape is a triangular shape, a triangular shape with an R chamfered at the top, or a semicircular shape, and the light control emitting surface is disposed on the side of the recess that intersects with the optical axis of the light emitting element. A first exit surface that is a convexly curved surface, and a front surface continuously disposed around the first exit surface On the opposite side of the back surface includes a second exit surface which is convex curved surface, and a configuration.
The light-emitting device of the present invention is a light-emitting element that emits light, the light flux control that is arranged such that the light-emitting element and the recess face each other, and the first emission surface intersects the optical axis of the light-emitting element. And a member.

  The surface light source device of the present invention employs a configuration having the light emitting device and a light diffusing member that diffuses and transmits light emitted from the light emitting device.

  The display apparatus of this invention takes the structure which has the said surface light source device and the to-be-illuminated member to which the light from the said surface light source device is irradiated.

  ADVANTAGE OF THE INVENTION According to this invention, the light which injects into the back surface of a light beam control member among the lights radiate | emitted from a light emitting element can be scattered. As a result, illuminance unevenness can be suppressed, the illuminance of the irradiated surface irradiated with light from the light flux controlling member can be made uniform, and high-quality illumination quality can be obtained.

The figure which shows typically the surface light source device which used the conventional LED as the light source. Configuration diagram showing a conventional display device Diagram for explaining the basic principle of the present invention The top view of the surface light source device which comprises the display apparatus which concerns on Embodiment 1 of this invention. Sectional drawing of the display apparatus cut | disconnected and shown along the X1-X1 line | wire of FIG. The top view of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention Sectional drawing of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention The bottom view of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention The perspective view which cuts off a part of back surface of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention, and shows the structure of a grid | lattice-like convex part typically The figure explaining the effect | action of the light beam control member by which the grid | lattice-like convex part was formed in the back surface of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention. The figure explaining the effect | action of the light beam control member whose back surface of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention is a smooth surface. The figure which shows the illumination intensity distribution of the light of the irradiation surface of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention. The figure explaining the convex part formed in the back surface of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention. The figure explaining the convex part and scattered light which are formed in the back surface of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention. The figure explaining the convex part and scattered light which are formed in the back surface of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention. The figure explaining the convex part and scattered light which are formed in the back surface of the light beam control member of the surface light source device which concerns on Embodiment 1 of this invention. Sectional drawing of the light beam control member of the light-emitting device concerning Embodiment 2 of this invention The perspective view which cuts off a part of back surface of the light-emitting device which concerns on Embodiment 2 of this invention, and shows the structure of a grid | lattice-like convex part typically Sectional drawing of the light beam control member of the light-emitting device which concerns on Embodiment 3 of this invention. The figure explaining a mode that light is retroreflected in the back surface of the light beam control member of the light-emitting device concerning Embodiment 3 of this invention. The figure explaining a mode that light is retroreflected in the back surface of the light beam control member of the light-emitting device concerning Embodiment 3 of this invention. The figure which shows the result of the simulation performed in order to verify the effect of the light-emitting device which concerns on Embodiment 3 of this invention. The figure which shows the variation of the light beam control member of the light-emitting device which concerns on Embodiment 3 of this invention. Sectional drawing of the light beam control member of the light-emitting device which concerns on Embodiment 4 of this invention. The figure which cuts off part of the back surface of the light beam control member of the variation 1 of the light-emitting device concerning Embodiment 5 of this invention, and shows the structure of a grid | lattice-like convex part typically The figure which cuts off part of the back surface of the light beam control member of the variation 2 of the light-emitting device concerning Embodiment 5 of this invention, and shows the structure of a grid | lattice-like recessed part typically The figure which cuts off part of the back surface of the light beam control member of the variation 3 of the light-emitting device concerning Embodiment 5 of this invention, and shows the structure of a grid | lattice-like convex part typically

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Principle explanation)
The basic concept of the present invention will be described.

  FIG. 3 is a diagram for explaining the basic principle of the present invention.

  Conventionally, no consideration has been given to light incident from the back surface of the light flux controlling member. As a result of experiments by the present inventors, when such light enters the light flux control member from the back surface of the light flux control member, the light flux control member condenses and emits this light, thereby causing uneven illumination on the irradiated surface. It was found to occur. However, it has been found that the illuminance unevenness cannot be prevented by simply making the back surface of the light flux controlling member rough.

  Therefore, the present inventors have found a configuration in which a plurality of convex portions or a plurality of concave portions are formed in a lattice shape on the back surface of the light flux controlling member in order to scatter light incident on the back surface of the light flux controlling member from the light emitting element. It was. This configuration has the following characteristics.

  FIG. 3 shows coordinate axes that serve as a guide when arranging the light flux controlling member. A light emitting point, which is one point on the emission surface of the light emitting element, is arranged at the origin O of the XYZ orthogonal coordinates, and the back surface of the light flux controlling member is placed on the surface S parallel to the XY plane away from the origin O and the reference light of the light flux controlling member. Arrange so that the axis coincides with the Z-axis. When the intersection point between the reference optical axis of the light flux controlling member and the surface S is a point P0, the point P1 on the intersection line between the virtual weight-shaped weight surface having the origin O as the vertex and the surface S, and the Z axis Is a point P2 obtained by rotating the point P1 by θ1 = 45 degrees with respect to the rotation axis as an incident point of light emitted from the origin O. For example, on the back surface of the light flux controlling member, if a plurality of projections (protrusions) or strip recesses (grooves) are formed in a lattice shape so that the ridge line extends in a direction orthogonal to the line P0-P1, Light emitted from the origin O can be refracted anisotropically. And the distance L1 from the reference optical axis of the point where the light incident from the point P1 reaches the irradiated surface S ′ parallel to the surface S, and the point where the light incident from the point P2 reaches the irradiated surface S ′. The distance L2 from the reference optical axis is different. Thereby, it can suppress that a ring-shaped specific bright part generate | occur | produces on a to-be-irradiated surface.

(Embodiment 1)
[Overall shape of surface light source device]
FIG. 4 is a plan view of the surface light source device constituting the display device according to Embodiment 1 based on the above basic concept. In FIG. 4, a member to be illuminated such as a liquid crystal display panel is not shown. FIG. 5 is a cross-sectional view of the display device of FIG. 4 taken along line X1-X1. The surface light source device of this embodiment is an example applied to a liquid crystal display panel.

  As shown in FIG. 4, the surface light source device 1 includes a plate-like light diffusing member 2, a light emitting element 3 as a point light source, and a light flux controlling member 4. The light diffusing member 2 is disposed on the back surface of an illuminated member such as a liquid crystal display panel and has substantially the same shape as the illuminated member. A plurality of light emitting elements 3 are arranged on the back surface side of the light diffusing member 2 at substantially equal intervals P. The light beam control member 4 controls the traveling direction of the light beam emitted from the light emitting element 3.

  The light emitting element 3 and the light flux controlling member 4 constitute a light emitting device 5.

  As shown in FIG. 5, the display device 6 includes the surface light source device 1 and a member 7 to be illuminated that is disposed on the light emission surface 8 (surface opposite to the back surface 9) side of the light diffusing member 2.

  The light diffusing member 2 is formed into a sheet shape or a flat plate shape using a resin material such as PMMA (polymethyl methacrylate) or PC (polycarbonate) having excellent light transmittance. The light diffusing member 2 is formed in substantially the same size as the planar shape of a member to be illuminated such as a liquid crystal display panel, an advertisement display panel, or a sign display panel.

  On the surface of the light diffusing member 2, fine irregularities (prism-like protrusions, irregularities formed by embossing or diffusion processing by bead coating) are formed, or a diffusing material is mixed inside the light diffusing member 2. The

  By this processing, the light diffusing member 2 diffuses while transmitting the light emitted from the light control emitting surface 11 (see FIG. 6) of the light flux controlling member 4, and uniformizes the light irradiated to the illuminated member.

  The light emitting element 3 is, for example, an LED. The light emitting elements 3 are arranged in a matrix on the back side of the light diffusing member 2.

  The light flux controlling member 4 is a diffusing lens that controls the traveling direction of the light emitted from the light emitting element 3, and is, for example, an aspheric lens. The light flux controlling member 4 is made of, for example, a transparent resin material such as PMMA (polymethyl methacrylate), PC (polycarbonate), EP (epoxy resin), or transparent glass.

[Overall shape of light flux controlling member 4]
6 to 8 are diagrams showing a detailed configuration of the light flux controlling member 4. 6 is a plan view thereof, FIG. 7A is a cross-sectional view taken along the line AA ′ in FIG. 6, FIG. 7B is an enlarged view of a portion C in FIG. 7A, and FIG. 4 is a bottom view of FIG.

  FIG. 7 is a view for explaining the shape of the light flux controlling member 4 including the reference optical axis L of the light emitting element 3. The reference optical axis L is a virtual light beam that is representative of the light beam, and refers to the traveling direction of light at the center of the three-dimensional light beam emitted from the light emitting element 3. In the present embodiment, a case where the optical axis of the light emitting element 3 (the optical central axis of the light emitting element 3) and the reference optical axis L are described as an example.

  As shown in FIGS. 6 to 8, the light flux controlling member 4 has a light control emitting surface 11, a back surface 12, and a recess 14. The light control emission surface 11 controls the emission direction when emitting the light emitted from the light emitting element 3 and incident on the light flux controlling member 4. The dent 14 allows the principal ray, which is light emitted within a predetermined angle range with respect to the reference optical axis direction, out of the light emitted from the light emitting element 3 to enter the inside. The back surface 12 extends in the radial direction from the opening edge of the recess 14 and makes a sub-light, which is light other than the principal light, emitted from the light-emitting element 3 at a large angle with respect to the reference optical axis, enter the inside. . On the back surface 12, lattice-like convex portions 13 that scatter light incident on the back surface 12 of the light flux controlling member 4 from the light emitting element 3 are formed.

  The light flux controlling member 4 is a round that is attached in a state where the light flux controlling member 4 is positioned on the substrate 18 (see FIG. 5), and a substantially annular flange 15 that projects radially outward of the light control emitting surface 11. A rod-shaped leg 16 and a protrusion 17 for guiding the positioning of the leg 16 are provided.

  As shown in FIG. 7A, the light control emission surface 11 protrudes upward (to the light diffusing member 2 side) from the flange portion 15.

  Three legs 16 are formed at equal intervals on the concentric circumference of the inner peripheral surface of the flange 15. The protrusion 17 corresponds to the positions of the three legs 16 and is formed to protrude outward in the radial direction of the flange portion 15.

  The light flux controlling member 4 is attached to the substrate 18 by the legs 16 being bonded to the surface 18 a (see FIG. 5) of the substrate 18 while being positioned with respect to the substrate 18.

  When the light flux controlling member 4 is attached to the substrate 18, a gap ε is formed between the light emitting surface of the light emitting element 3 and the back surface 12 (reference surface) of the light flux controlling member 4 (see FIG. 5). The reason why the gap ε is formed is, for example, a negative reason for mounting errors when the light flux controlling member 4 is placed on the substrate 18 so that the light emitting element 3 is accommodated in the recess 14, or a light emitting element There is a positive reason such as the purpose of radiating the heat generated from 3.

[Light Control Exit Surface 11 of Light Beam Control Member 4]
The light control exit surface 11 of the light flux controlling member 4 has a first exit surface 11a located in a predetermined range centered on the optical axis L, and a second formed continuously around the first exit surface 11a. It consists of an exit surface 11b and a third exit surface 11c that connects the second exit surface 11b and the flange 15.

  As shown in FIG. 7A, the first emission surface 11a has a smooth curved surface convex downward, and is formed in a concave shape obtained by cutting off a part of a sphere. Further, the second emission surface 11b is formed in a continuous shape with the first emission surface 11a, has a smooth curved surface shape that is convex upward, and has a substantially hollow disk shape in which the planar shape surrounds the first emission surface 11a. Is formed. Moreover, the 3rd output surface 11c is formed continuously with the 2nd output surface 11b, and the cross section is formed as a substantially linear inclined surface. The third exit surface 11c may be formed in a curved shape as long as the third exit surface 11c does not obstruct a wide and uniform exit from the light flux controlling member 4.

[Lattice-like convex portion 13 of light flux controlling member 4]
As described above, the light flux controlling member 4 is supported on the substrate 18 by the legs 16, and a gap ε for heat dissipation or the like is provided between the back surface 12 of the light flux controlling member 4 and the light emitting surface of the light emitting element 3. Is formed. Since the gap ε is formed, a part of the light emitted from the light emitting surface of the light emitting element 3 enters the light flux controlling member 4 from the back surface 12 of the light flux controlling member 4. When the back surface 12 is a smooth surface, the light reaching the back surface 12 of the light beam control member 4, that is, the lens bottom surface, is refracted near the reference optical axis L, enters the light beam control member 4, and exits from the light control light output surface 11. To do. The emitted light is not light that can be controlled so as to be smoothly spread and emitted by the light flux controlling member 4, but is unintentionally condensed by passing through the smooth back surface 12 and the light-controlled emitting surface 11, and is subject to being covered. An annular bright portion is formed on the irradiated surface, resulting in uneven illuminance (described later with reference to FIG. 12B).

  In the present embodiment, a lattice-like convex portion 13 is formed on the back surface 12 of the light flux controlling member 4, and light incident on the back surface 12 of the light flux controlling member 4 is scattered by the lattice-like convex portion 13. That is, a light beam incident from an arbitrary light incident point P1 on the back surface 12 and a light beam incident from a light incident point P2 obtained by rotating the light incident point by 45 degrees about the reference optical axis L as a rotation axis, The angle with respect to the normal line of the back surface 12 at the light incident point is different. Therefore, the irradiated portion (light reaching the irradiated surface is irradiated on the irradiated surface obtained by light incident from each point on the locus obtained by rotating the light incident point P1 360 degrees with the reference optical axis L as the rotation axis. The trajectory to be drawn is not circular but scattered over a wide range.

  In addition, the shape of each filament of the grid | lattice-shaped convex part 13 should just be able to fully scatter the light which injects into the back surface 12 of the light beam control member 4, and is a cross section orthogonal to the direction where a protrusion extends. The shape may be a triangular shape, a triangular shape having a chamfered chamfer at the top, or a semicircular shape, and an R shape may be added to a groove between these filaments. In consideration of transferability for transferring the light flux controlling member 4 from the mold, each protrusion of the grid-like convex portion 13 is preferably a curved surface, but for the purpose of preventing light from being refracted in the optical axis direction, a triangular cross section is used. Shape is preferred. In addition, it has been found by experiments by the present inventors that the convex portions are preferably arranged in a lattice pattern in order to sufficiently scatter the light incident on the back surface 12 of the light flux controlling member 4.

  As shown in FIG. 7A and FIG. 8, lattice-like convex portions 13 are formed on the back surface 12 of the light flux controlling member 4. The grid-like convex portion 13 is characterized in that (1) it is a convex portion and (2) it is in a grid shape.

(1) Convex portion As shown in FIG. 7 (b), the lattice-like convex portion 13 includes a plurality of linear convex portions 13 a protruding outward from the back surface 12 of the light flux controlling member 4, and their ridge lines. Are arranged so that they are parallel to each other, and convex portions 13b (see FIG. 9 to be described later) orthogonal to these are arranged so that their ridgelines are parallel. The cross-sectional shape of the convex portion 13a orthogonal to the extending direction of the filament is a shape close to a semicircle, and is a triangular shape with the top chamfered in an R shape. For example, the length of the bottom surface of the convex portion 13a is 0.5 mm, the bottom angle of the inclined surface forming the filament is 45 °, and the tip R is 0.2 mm. Although the inclination angle of the convex portion 13a may be smaller than 45 °, the inclination angle of the convex portion 13a is preferably 45 ° or more for the purpose of scattering light incident on the back surface 12 of the light flux controlling member 4.

  The lattice-shaped convex portion 13 is integrally formed on the back surface 12 of the light flux controlling member 4 by being transferred from a mold using a transparent resin material such as PMMA, PC, EP together with the light flux controlling member 4 body. For this reason, when the inclination angle of the convex portion 13a is large, in order to obtain the transfer accuracy required at the time of molding, it is easy to transfer the resin or mold at a high temperature, or the pressure is sufficiently maintained to suppress sink marks. Therefore, it takes time for the cooling time and the pressure holding time, which may increase the cost.

  In the present embodiment, by making the cross-sectional shape of the convex portion 13a substantially semicircular, the lattice-shaped convex portion 13 can sufficiently scatter light incident on the back surface 12 of the light flux controlling member 4, and Transfer from the mold when forming the light flux controlling member 4 can be facilitated and the manufacturing cost can be reduced.

(2) Lattice Shape As shown in FIG. 8, the lattice-like convex portion 13 is formed by the plurality of convex portions 13a and convex portions 13b orthogonal thereto (see FIG. 9 described later). Here, the grid-shaped convex part 13 should just be provided in the predetermined area | region from the center of the back surface 12 of the light beam control member 4 toward an outer peripheral surface. In FIG. 8, the lattice-like convex portion 13 is formed up to the substantially inner peripheral surface of the leg 16. The grid-shaped convex portion 13 may be formed on the entire back surface 12 of the light flux controlling member 4.

  FIG. 9 is a perspective view schematically showing the structure by cutting a part of the grid-like convex portion 13.

  As shown in FIG. 9, the grid-like convex part 13 is formed by making a plurality of convex parts 13a and a plurality of convex parts 13b having a substantially semicircular cross-sectional shape orthogonal to each other in a grid pattern. By forming the convex portions in a lattice shape, a cone symmetrical to the reference optical axis L with one point on the light emitting surface of the light emitting element 3 as an apex is arranged so that the bottom surface of the cone overlaps the back surface 12 of the light flux controlling member 4. Is virtually arranged, the shape connecting the intersection of the back surface 12 with the light beam that exits from the apex of the cone and travels along the weight surface matches the peripheral shape (circular shape) of the bottom surface of the cone. However, the shape formed on the illuminated surface of the illuminated member 7 by the intersection of the light beam emitted from the light flux controlling member 4 after passing through these intersections and the illuminated member 7 is not circular. Therefore, the light incident on the back surface 12 of the light flux controlling member 4 can be scattered in both the vertical direction and the horizontal direction. On the other hand, if the convex portions are formed in a radial pattern from the center without forming a lattice shape, or conical protrusions are formed at a uniform pitch, a strong regular light collection pattern is formed on the irradiated surface. In some cases, the light is collected, and there is a possibility that light is collected in a narrow range on the irradiated surface and a specific bright portion is generated.

  Further, when the convex portions are formed in a lattice shape, it has been found that the illuminance value of the bright portion is lower than that when the back surface 12 is smooth. In this way, when the convex portions are formed in a lattice shape, a mold necessary for transferring a shape sufficient to scatter light by injection molding or the like can be easily processed, thereby reducing the manufacturing cost. be able to.

[Operation of luminous flux control member 4]
Hereinafter, the operation of the light flux controlling member 4 configured as described above will be described.

  FIG. 10 is a diagram for explaining the operation of the light beam control member 4 in which the lattice-shaped convex portions 13 are formed on the back surface 12 of the light beam control member 4. FIG. 11 is a diagram for explaining the operation of the light flux controlling member 4 in which the back surface 12 of the light flux controlling member 4 is a smooth surface (that is, a smooth surface that does not form the grid-like convex portions 13). FIG. 12 is a diagram showing the illuminance distribution of the light on the irradiated surface by the light emitted from the light flux controlling member 4, and is the illuminance distribution on the back surface (irradiated surface) of the light diffusing member 2. 12A shows the illuminance distribution on the irradiated surface by the light irradiated from the light flux controlling member 4 on which the grid-like convex portions 13 of FIG. 10 are formed, and FIG. 12B shows the back surface 12 of FIG. An illuminance distribution on the irradiated surface by light irradiated from the smooth surface light flux controlling member 4 is shown as a comparative example of the first embodiment. The vertical axis and the horizontal axis represent dimensions from the reference optical axis L of the light emitting device 5.

  First, as shown in FIG. 10 and FIG. 11, most of the light emitted from the light emitting element 3 is in the range of the half-value width, and enters the light flux control member 4 from the recess 14. After propagating through the inside, the light is emitted from the first emission surface 11a to the third emission surface 11c to the outside (in the air) according to Snell's law. At this time, the light beam emitted from the light beam control member 4 spreads smoothly toward the irradiation range.

  However, since a gap ε is formed between the back surface 12 of the light flux controlling member 4 and the substrate 18 (see FIG. 5), light enters the gap ε from the light emitting surface of the light emitting element 3 and enters. Light enters the light flux control member 4 from the back surface 12 of the light flux control member 4.

  As shown in FIG. 11, when the back surface 12 of the light beam control member 4 is a smooth surface, that is, when the lattice-shaped convex portion 13 is not formed on the light beam control member 4, the light beam control member 4 is incident on the back surface 12 (lens bottom surface). The transmitted light travels in the light flux controlling member 4 in a state of being refracted toward the reference optical axis L, and is emitted from the second emission surface 11b and the third emission surface 11c. As a result, due to refraction at the entrance surface to the light flux controlling member 4 and condensing at the convex lens-shaped exit surface of the light flux controlling member 4, the light condensing portion (bright portion) is on the irradiated surface from the other portions. Further, an annular illuminance unevenness 21 that shines brightly and annularly occurs. The annular illuminance unevenness 21 is visually recognized from the light exit surface side of the light diffusing member 2 and deteriorates the illumination quality.

  On the other hand, in the present embodiment, the light incident on the back surface 12 of the light beam control member 4 is scattered by forming the lattice-like convex portions 13 on the back surface 12 of the light beam control member 4.

  As shown in FIG. 10, when the grid-like convex portion 13 is formed on the back surface 12 of the light flux controlling member 4, the back surface 12 (lens bottom surface) of the light flux controlling member 4 in order to scatter light by the grid-like convex portion 13. The light incident on the light is emitted from the light flux controlling member 4 toward the wide range of the irradiated surface without being condensed near the reference optical axis L. As a result, as shown in FIG. 12A, the illuminance unevenness 22 on the irradiated surface is significantly reduced. In FIG. 12A, for the sake of convenience of explanation, it is expressed as illuminance unevenness 22, but in reality, this light intensity difference is small, and it is not necessary to call it illuminance unevenness 22. In addition, the illuminance unevenness 22 is not only the light intensity difference is suppressed to be much smaller than the annular illuminance unevenness 21 in FIG. Since it has a discrete shape, light gathered parts (bright parts) are dispersed, and the illuminance unevenness is less noticeable. The reason why the uneven illuminance 22 in FIG. 12A has a discrete cross shape is that the lattice-shaped convex portions 13 are square lattices.

  By the way, if the optical path of the light incident from the back surface 12 of the light flux controlling member 4 can be scattered, it is considered that the same effect as this embodiment can be obtained. However, it has been found by experiments of the present inventors that a sufficient effect may not be obtained with a simple diffusion surface.

  As a general method for diffusing light, it is conceivable to form a rough surface on the back surface 12 of the light flux controlling member 4. The rough surface can be easily produced by etching the surface of the light flux controlling member 4 to be a mold and roughening the surface.

  FIG. 13 is a diagram for explaining a convex portion formed on the back surface 12 of the light flux controlling member 4. FIG. 13A shows the convex portions of the grid-like convex portions 13. Moreover, FIG.13 (b) shows the back surface 12 which performed the rough surface process. FIG. 13C shows a roughened mold surface for forming a rough surface on the back surface 12 and the back surface 12 onto which the shape has been transferred.

  As shown in FIG. 13C, in the rough surface treatment using a general etchant, the transfer surface 31 formed on the mold is very fine (μ order unit). Even if such fine processing is applied to the back surface 12 of the light flux controlling member 4, the incident light cannot be sufficiently scattered. However, the addition of such fine irregularities to the grid-like convex portions 13 of the present embodiment exhibits the effect of further diffusing light. This point will be described later in the second embodiment.

  Further, when the light flux control member 4 is transferred and formed from the transfer surface 32 of the mold by injection molding or the like, the back surface 12 of the light flux control member 4 is not suitable if the temperature setting and holding pressure of the resin and the mold are not appropriate. As shown in FIG. 13 (c), the processed surface 31 is more uneven than the fine unevenness of the transfer surface 32 of the mold, and the incident light cannot be sufficiently scattered. If the transfer is to be performed more accurately from the transfer surface 32 of the mold, the molding cycle becomes longer, requiring a great deal of time and adjustment, resulting in an increase in cost.

  In addition, by performing a rough surface treatment using a special etchant or a file, the height d of the rough surface 33 in FIG. 13B is set to about the convex portion 13a of the lattice-shaped convex portion 13 in FIG. Then, the incident light can be scattered. However, the present inventors have found that such rough surface treatment has the following disadvantages in addition to the cost increase. That is, it is necessary to obtain a sufficient amount of height difference d for one convex portion of the rough surface 33 by the rough surface treatment of the back surface 12 of the light flux controlling member 4, whereas the rough surface shown in FIG. If the molding cycle of the surface 33 is slightly shortened, transfer becomes insufficient, and a necessary amount of height difference d cannot be obtained. On the rough surface 33 where such a sufficient height difference d cannot be obtained, the light irradiated from the light emitting surface of the light emitting element 3 is subjected to the light flux control for the same reason as the case where the back surface 12 of the light flux controlling member 4 is a smooth surface. The light is refracted toward the reference optical axis L on the back surface 12 (lens bottom surface) of the member 4. Therefore, after the light is emitted from the light flux controlling member 4, it is condensed on the irradiated surface, and illuminance unevenness occurs.

  As described above, the general rough surface treatment cannot sufficiently scatter the optical path of the light incident from the back surface 12 of the light flux controlling member 4. In the rough surface treatment used for general purposes, even if the convex portion can be formed, when viewed optically, illuminance unevenness similar to that when the back surface 12 is a smooth surface is generated.

  Therefore, in the present embodiment, as shown in FIG. 13A, a grid pattern is formed on the back surface 12 of the light flux controlling member 4 instead of the rough surface processing that forms a processing surface with a small height difference using an etchant or a file. The convex portion 13 is formed with high accuracy.

[Explanation of convex part and scattered light]
14 to 16 are diagrams for explaining the convex portion 13a formed on the back surface 12 of the light flux controlling member 4 and the scattered light of the light incident thereon. In FIG. 14A, the direction of the light incident on the back surface 12 when the convex portion 13 a is formed on the back surface 12 of the light flux controlling member 4 so as to be parallel to the X axis of the XYZ orthogonal coordinates is viewed from the back surface 12 side. The figure is shown. Moreover, FIG.14 (b) shows typically the shape which looked at Fig.14 (a) from the side surface (X-axis direction). FIG. 15A shows the direction of light rays incident on the convex portion 13a of the back surface 12 of the light flux controlling member 4 shown in FIG. FIG. 15B shows the operation of the convex portion 13a of the back surface 12 of the light flux controlling member 4 that is received by light incident from the orthogonal direction. FIG. 16A shows the direction of light rays incident on the convex portion 13 a of the back surface 12 of the light flux controlling member 4 from an oblique 45 ° direction. FIG. 16B shows the operation of the convex portion 13a of the back surface 12 of the light flux controlling member 4 that is received by light incident from an oblique 45 ° direction. Note that one of the light beams shown in FIG. 15B matches the light beam indicated by the line O-P1 in FIG. 3, and one of the light beams shown in FIG. This coincides with the light beam indicated by the line OP2 in FIG.

  As shown in FIG. 14B, a convex portion 13 a is formed on the back surface 12 of the light flux controlling member 4. As shown in FIG. 14A, a light ray direction x parallel to the convex portion 13a and a light ray direction orthogonal to the convex portion 13a are taken.

  As shown in FIG. 15 (a), when light is incident on the convex portion 13a of the back surface 12 of the light flux controlling member 4 from the orthogonal direction, the light incident on the convex portion 13a as shown in FIG. 15 (b). The incident angle varies. For this reason, the light incident on the back surface 12 (lens bottom surface) of the light flux controlling member 4 is emitted from the light control emitting surface 11 of the light flux controlling member 4 as the scattered light without being condensed.

  As shown in FIG. 16 (a), when the light beam is incident on the convex portion 13a of the back surface 12 of the light flux controlling member 4 from an oblique direction of 45 °, the light beam enters the convex portion 13a as shown in FIG. 16 (b). The incident angle of the emitted light varies. In addition, since light is incident on the convex portion 13a at an angle (in this case, oblique 45 °), the incident angle of light also varies in the height and depth directions of the paper surface of FIG. For this reason, the light incident on the back surface 12 (lens bottom surface) of the light flux controlling member 4 is emitted from the light control emitting surface 11 of the light flux controlling member 4 as the scattered light without being condensed.

  As described above in detail, in the present embodiment, a lattice-like convex made of a plurality of filaments that scatter light incident on the back surface of the light beam control member 4 from the light emitting element 3 on the back surface 12 of the light beam control member 4. Part 13 was formed. Thereby, the light incident on the back surface 12 (lens bottom surface) of the light flux controlling member 4 is scattered without being collected, and is emitted from the light control emitting surface 11 toward a wide range on the irradiated surface. As a result, as shown in FIG. 12A, it is possible to suppress illuminance unevenness on the irradiated surface, to make the illuminance uniform, and to obtain high quality illumination quality.

  Further, in the present embodiment, when the light flux control member 4 is attached to the substrate 18, the light flux control is performed when a gap ε is formed between the light emitting surface of the light emitting element 3 and the back surface 12 of the light flux control member 4. Condensing light incident on the back surface 12 (lens bottom surface) of the member 4 toward the reference optical axis L is suppressed. As described above, since the gap ε between the light emitting surface of the light emitting element 3 and the back surface 12 of the light flux controlling member 4 is allowed in the present embodiment, excessive mounting accuracy is not required. Therefore, this embodiment can reduce the cost, for example, by using a general-purpose light-emitting element 3 instead of an expensive one that is reduced to a size that can be accommodated in the recess 14.

  For the same reason, the present embodiment can obtain high quality illumination quality even when the entire area of the back surface 12 of the light flux controlling member 4 can be the incident surface. In addition, this embodiment can provide a high-quality irradiation surface even when the light flux controlling member is disposed at a position away from the light emitting element by a predetermined dimension, and can suppress adverse effects caused by heat generated by the light emitting element. it can.

(Embodiment 2)
[Overall shape of luminous flux control member]
FIG. 17 is a cross-sectional view of a light flux controlling member of the light emitting device according to Embodiment 2. FIG. 17A is a cross-sectional view of the light flux controlling member, and FIG. 17B is an enlarged view of a portion C shown in FIG. In FIG. 17, the same reference numerals are given to the same components as those in FIG.

  The light flux controlling member 40 is used in place of the light flux controlling member 4 of FIGS.

  The light flux controlling member 40 shown in FIG. 17A is different from the light flux controlling member 4 shown in FIG. 7A in the shape of the lattice-like convex portion 43 from the shape of the lattice-like convex portion 13.

  The lattice-shaped convex portions 43 are integrally formed on the back surface 12 of the light flux controlling member 40 by being transferred from a mold using a transparent resin material such as PMMA, PC, EP together with the light flux controlling member 40 main body.

  As shown in FIG. 17B and FIG. 18, the lattice-like convex portion 43 includes a plurality of linear convex portions 43 a that protrude outward from the back surface 12 of the light flux controlling member 40, and their ridge lines are parallel to each other. And a plurality of linear protrusions 43b orthogonal to these are arranged so that their ridgelines are parallel. And a recessed part is formed between the convex part 43a and the convex part 43a which adjoin, and the convex part 43b and the convex part 43b. On the surfaces of the convex portions 43a and the convex portions 43b, fine concave and convex surfaces 43c are formed.

  FIG. 18 is a perspective view schematically showing the structure of the lattice-shaped convex portion by cutting out a part of the lattice-shaped convex portion 43, and corresponds to FIG.

  As shown in FIG. 18, the lattice-shaped convex portion 43 is formed by orthogonally crossing a plurality of convex portions 43 a and a plurality of convex portions 43 b having a substantially semicircular cross-sectional shape. By forming the convex portions in a lattice shape, light incident on the back surface 12 of the light flux controlling member 40 can be scattered in both the vertical direction and the horizontal direction.

  The cross-sectional shape of the convex portion 43a is a shape close to a semicircle. For example, the bottom length of the convex portion 43a is 0.5 mm, the base angle is 45 °, and the tip R is 0.2 mm. The inclination angle of the convex portion 43a may be 45 ° or more or smaller than 45 °. For the purpose of appropriately scattering the light incident on the back surface 12 of the light flux controlling member 40, the inclination angle of the convex portion 43a is preferably 45 ° or more.

  The fine uneven surface 43c is a rough surface of about 70 μm formed on the surface of the convex portion 43a. The fine concavo-convex surface 43c is produced by roughening the mold on which the convex portions 43a are formed by etching.

  As described above, according to the present embodiment, the light incident on the back surface 12 of the light flux controlling member 40 can be appropriately scattered by forming the grid-like convex portions 43 on the back surface 12 of the light flux controlling member 40. And by forming the surface of the convex part 43a and the convex part 43b in the fine uneven surface 43c, scattering performance can be improved and illuminance nonuniformity can be suppressed further.

(Embodiment 3)
[Overall shape of luminous flux control member]
In the said Embodiment 1, 2, the invention which scatters the light which injects into the back surface 12 by providing the grid-like convex part 13 (43) in the back surface 12 of the light beam control member 4 (40) was demonstrated.

  The present inventors further devise the shape of the grid-like convex portion 13 to retroreflect the light reflected by the light diffusing member 2 and increase the amount of the retroreflected light. It was found that the effect of being able to be obtained is also obtained.

  In the third embodiment, an invention of the shape of the lattice-shaped convex portion 13 for increasing the amount of light retroreflected will be described.

  FIG. 19 is a cross-sectional view of the light flux controlling member of the light emitting device according to the present embodiment. FIG. 19A is an overall cross-sectional view of the light flux controlling member, and FIG. 19B is an enlarged view of a portion C shown in FIG. In FIG. 19, the same components as those in FIG.

  The light flux controlling member 50 is used in place of the light flux controlling member 4 shown in FIGS.

  In the light flux controlling member 50 shown in FIG. 19A, the shape of the lattice-like convex portion 53 is different from the shape of the lattice-like convex portion 13 as compared with the light flux controlling member 4 shown in FIG.

  The lattice-like convex portion 53 is integrally formed on the back surface 12 of the light flux controlling member 50 by being transferred from a mold using a transparent resin material such as PMMA, PC, EP together with the light flux controlling member 50 main body.

  As shown in FIG. 19B, the lattice-like convex portion 53 is formed of a plurality of linear convex portions 53 a that protrude outward from the back surface 12 of the light flux controlling member 50 so that their ridge lines are parallel to each other. And a plurality of linear protrusions 53b orthogonal to these are arranged so that their ridge lines are parallel to each other. A quadrangular pyramid recess is formed between the adjacent protrusions 53a and 53a and between the protrusions 53b and 53b. The cross-sectional shape of the convex part 53a and the convex part 53b orthogonal to the extending direction of the filament is an isosceles triangle.

  Note that the grid-like convex portion 53 may be provided in a predetermined region from the center of the back surface 12 of the light flux controlling member 50 toward the outer peripheral surface, and may be formed on the entire back surface 12 of the light flux controlling member 50.

[Explanation of the convex portion 53a of the grid-like convex portion 53 and the retroreflected light]
A part of the light emitted from the light control exit surface 11 of the light flux controlling member 50 does not pass through the light diffusing member 2 (see FIG. 5) and is reflected by the light diffusing member 2. A part of the light reflected by the light diffusing member 2 enters the light control emission surface 11.

  As shown in FIG. 19, by forming the cross-sectional shape of the convex portion 53a of the lattice-like convex portion 53 into an isosceles triangle, the light incident on the light control emission surface 11 is retroreflected by the convex portion 53a, The light is emitted again from the light control exit surface 11.

  20 and 21 are diagrams for explaining how the light reflected by the light diffusing member 2 and incident on the light control emission surface 11 is retroreflected by the convex portion 53a. 20 shows a case where the inclination angle θ, which is an angle formed between the bottom surface (reference surface) and the pyramid surface, is 45 °, and FIG. 21 shows a case where the inclination angle θ is 55 °. 20B is an enlarged view of a C portion in FIG. 20A, and FIG. 21B is an enlarged view of a C portion in FIG.

  As shown in FIG. 20, when θ = 45 °, a part of the light 54 incident on the light control emission surface 11 from the direction perpendicular to the reference surface is totally reflected within one convex portion 53a and again. The light is emitted from the light control exit surface 11.

  On the other hand, as shown in FIG. 21, when θ = 55 °, a part of the light 54 incident on the light control emission surface 11 from the direction perpendicular to the reference surface is reflected between the plurality of convex portions 53a. The light passes through while being refracted and is emitted again from the light control exit surface 11.

  The light totally reflected within one convex portion 53a is brighter than the light emitted through the plurality of convex portions 53a while being reflected or refracted. That is, the amount of retroreflected light is large.

  However, in the case of θ = 45 °, some of light incident from directions other than the direction perpendicular to the reference plane is emitted while being reflected or refracted between the plurality of convex portions 53a. is there. Therefore, it cannot be generally said that the amount of retroreflected light is the largest when θ = 45 °.

〔simulation result〕
Therefore, the inventors performed a simulation on the relationship between the inclination angle θ and the amount of retroreflected light in order to verify the effect of the present embodiment. FIG. 22 is a diagram showing the simulation result.

  The horizontal axis in FIG. 22 indicates the inclination angle θ. The vertical axis in FIG. 22 represents the ratio of the amount of light reaching the front surface 18a (light receiving surface) of the substrate 18 with respect to the case where the inclination angle is 0 ° (the back surface 12 is flat).

  That is, the smaller the value on the vertical axis in FIG. 22, the more light is retroreflected. As shown in FIG. 22, it has been found by simulation that the amount of retroreflected light becomes the maximum when the inclination angle θ is approximately 55 °.

〔variation〕
As shown in FIG. 10, the amount of light incident on the back surface 12 increases as the distance from the light emitting element 3 increases.

  Therefore, as shown in FIG. 23, processing (texture processing or the like) mainly for light scattering is performed in a region 55 at a predetermined distance from the center of the back surface 12, and the main region is applied to another region 56 of the back surface 12. Alternatively, processing for retroreflection (processing for providing the lattice-like convex portions 53) may be performed. Thus, a light scattering portion is formed in the region 55 (inner region) near the periphery of the recess 14 where light from the light emitting device 3 is likely to be incident, and the light emitting device 3 is a region away from the recess 14 on the back surface 12. By forming the retroreflective portion in the region 56 (outer region) where it is difficult for light from reaching, it is possible to effectively exhibit the two functions of light scattering and retroreflection.

  As described above, according to the present embodiment, the light diffusion is performed by forming the grid-like convex portions 53 on the back surface 12 of the light flux controlling member 50 by the convex portions 53a and 53b having an isosceles triangular section. Since the light reflected by the member 2 is retroreflected and re-irradiated to the light diffusing member 2, it can be used effectively, so that the amount of decrease in luminance on the display surface can be reduced.

  In order to reduce the amount of decrease in luminance on the display surface, a reflective sheet may be provided on the surface 18a of the substrate 18 of the display device. According to the present embodiment, the light retroreflected by the light flux controlling member 50 is transmitted through the light diffusing member 2 and irradiated onto the display surface (irradiated surface). Even if a reflective sheet is not provided in the portion, uneven luminance on the display surface can be suppressed, and high-quality illumination quality can be obtained.

(Embodiment 4)
In the fourth embodiment, a case where a plurality of concave portions are formed in a lattice shape on the back surface of the light flux controlling member will be described.

  FIG. 24 is a cross-sectional view of the light flux controlling member of the light emitting device according to the present embodiment. FIG. 24A is an overall cross-sectional view of the light flux controlling member, and FIG. 24B is an enlarged view of a portion C shown in FIG. In FIG. 24, the same components as those in FIG.

  The light flux controlling member 60 is used in place of the light flux controlling member 50 shown in FIGS.

  The light flux controlling member 60 shown in FIG. 24A is different from the light flux controlling member 50 shown in FIG. 19A in that a lattice-shaped concave portion 63 is formed instead of the lattice-shaped convex portion 53. . A concave portion 63a is formed instead of the convex portion 53a of the light flux controlling member 50, and a concave portion 63b is formed instead of the convex portion 53b.

  The grid-shaped concave portion 63 has a plurality of concave concave portions 63a arranged on the back surface 12 of the light flux controlling member 60 so that their ridge lines are parallel to each other, and a plurality of concave concave portions 63b orthogonal to these are arranged on the ridge lines. Are arranged so as to be parallel to each other. And the convex part 63c of a quadrangular pyramid is formed between the recessed part 63a and the recessed part 63a which adjoin, and the recessed part 63b and the recessed part 63b.

  The plurality of quadrangular pyramid protrusions 63c projecting outward from the back surface 12 of the light flux controlling member 60 are transferred from the mold together with the light flux controlling member 60 main body using a transparent resin material such as PMMA, PC, EP or the like. And are integrally formed.

  Note that the lattice-shaped recess 63 may be provided in a predetermined region from the center of the back surface 12 of the light flux controlling member 60 toward the outer peripheral surface, and may be formed on the entire back surface 12 of the light flux controlling member 60.

  Also according to the present embodiment, light incident on the back surface of the light flux controlling member from the light emitting element can be scattered.

(Embodiment 5)
In each of the above embodiments, the case where a plurality of concave portions or a plurality of convex portions are formed in a square lattice shape on the back surface of the light flux controlling member has been described. However, the present invention is not limited to this, and a plurality of concave portions or a plurality of convex portions are provided. May be formed in a three-way lattice shape or a hexagonal lattice shape.

  In the fifth embodiment, a case will be described in which a plurality of concave portions or a plurality of convex portions are formed in a three-sided lattice shape or a hexagonal lattice shape on the back surface of the light flux controlling member.

[Variation 1]
Variation 1 of the present embodiment is a case where a plurality of convex portions are formed in a three-way lattice pattern on the back surface of the light flux controlling member. FIG. 25 is a diagram schematically showing the structure of the lattice-shaped recess by cutting out a part of the back surface of the light flux controlling member of variation 1 of the light emitting device according to the present embodiment. FIG. 25A is a perspective view, FIG. 25B is a bottom view, and FIG. 25C is a side view.

  As shown in FIG. 25, the grid-like convex portion 73 is arranged with a plurality of linear convex portions 73a protruding outward from the back surface of the light flux controlling member, and the plurality of convex portions 73b with respect to the convex portion 73a. The projections 73c are arranged so as to form 60 °, and the projections 73c are arranged so as to form 60 ° with respect to the projections 73a and 73b. A concave portion of a triangular pyramid is formed in a portion surrounded by the convex portion 73a, the convex portion 73b, and the convex portion 73c. The cross-sectional shape of the convex part 73a, the convex part 73b, and the convex part 73c orthogonal to the extending direction of a filament is an isosceles triangle.

[Variation 2]
Variation 2 of the present embodiment is a case where a plurality of recesses are formed in a three-way lattice pattern on the back surface of the light flux controlling member. FIG. 26 is a diagram schematically showing the structure of the lattice-shaped recess by cutting out a part of the back surface of the light flux controlling member of the variation 2 of the light emitting device according to the present embodiment. 26A is a perspective view, FIG. 26B is a bottom view, and FIG. 26C is a side view.

  As shown in FIG. 26, the lattice-shaped concave portion 83 is formed with a plurality of triangular pyramid convex portions 83d protruding outward from the back surface of the light flux controlling member. The triangular pyramid convex portion 83d is a three-way lattice formed so that the plurality of linear concave portions 83a, the plurality of concave portions 83b, and the plurality of concave portions 83c intersect at 60 °. It is formed in the enclosed part.

[Variation 3]
Variation 3 of the present embodiment is a case where a plurality of convex portions are formed in a hexagonal lattice pattern on the back surface of the light flux controlling member. FIG. 27 is a bottom view schematically showing the structure of the lattice-shaped recess by cutting out a part of the back surface of the light flux controlling member of variation 3 of the light emitting device according to the present embodiment.

  As shown in FIG. 27, the lattice-shaped convex portion 93 is formed by arranging hexagonal ridge lines (thick line convex portions 93a in FIG. 27) in a hexagonal lattice pattern on the back surface of the light flux controlling member. And the hexagonal pyramid recessed part enclosed by the hexagonal convex part 93a is formed.

[Variation 4]
Variation 4 of the present embodiment is a case where a plurality of recesses are formed in a hexagonal lattice pattern on the back surface of the light flux controlling member. The light flux controlling member of variation 4 is formed with a hexagonal groove (thick line concave portion 103a in FIG. 27) instead of the hexagonal convex portion 93a in variation 3 described above.

  The lattice-shaped recess 103 is formed by arranging hexagonal grooves (recesses) 103a in a hexagonal lattice pattern on the back surface of the light flux controlling member. And the convex part of the hexagonal pyramid enclosed by the hexagonal recessed part 103a is formed.

  Also in each variation of the present embodiment, light incident on the back surface of the light flux controlling member from the light emitting element can be scattered.

  In addition, when the filament is formed in the product (light flux controlling member) as in variation 1 in the first embodiment, the second embodiment, the third embodiment, and the fifth embodiment, it is easy to process the mold. It is.

  The above description is an illustration of a preferred embodiment of the present invention, and the scope of the present invention is not limited to this.

  For example, the light diffusing member may be attached to the surface of the illuminated member on the light emitting element side, or in a state separated from the illuminated member, disposed on the surface of the illuminated member facing the light emitting element. You may do it.

  The light flux controlling member may be formed with a textured surface on the light control exit surface to diffuse light emitted from the light control exit surface.

  The light flux controlling member may be formed of a material containing a light diffusing substance (for example, silicone particles or titanium oxide).

  In the above embodiments, the names of the light emitting device, the surface light source device, and the display device are used. However, this is for convenience of explanation and may be a planar light source, a display element, or the like.

  The light flux controlling member, the light emitting device, the surface light source device, and the display device according to the present invention can be widely used in applications such as a backlight of a monitor of a television monitor or a personal computer, an indoor indicator light, and various illuminations.

DESCRIPTION OF SYMBOLS 1 Surface light source device 2 Light-diffusion member 3 Light-emitting element 4, 40, 50, 60 Light flux control member 5 Light-emitting device 6 Display apparatus 7 Illuminated member 11 Light-control emission surface 12 Back surface 13, 43, 53, 73, 93 Grid-shaped convex Portions 13a, 13b, 43a, 43b, 53a, 53b, 73a, 73b, 73c, 93a 103a Recess 93a Ridge line

Claims (11)

A light flux controlling member for controlling the traveling direction of light emitted from the light emitting element,
A light control exit surface for controlling the traveling direction of the light emitted from the light emitting element;
A recess located on the opposite side of the light control exit surface;
A back surface extending in a radial direction from the opening edge of the recess,
On the back surface, a grid-like convex part in which convex parts of a plurality of filaments are arranged in a grid pattern, or a grid-like concave part in which concave parts of a plurality of filaments are arranged in a grid pattern are formed,
The protrusions of the filaments or the recesses of the filaments, the cross-sectional shape orthogonal to the extending direction of the filaments is a triangular shape, a triangular shape with an R chamfer on the top, or a semicircular shape,
The light control emission surface is continuously arranged around the first emission surface, which is a curved surface convex toward the dent and arranged so as to intersect the optical axis of the light emitting element, and around the first emission surface. look including a second exit surface which is convex curved in the opposite side of the back was,
The projections of the filaments or the recesses of the filaments are roughened,
Luminous flux control member.   The light flux controlling member according to claim 1, wherein the lattice is a square lattice.   The light flux controlling member according to claim 1, wherein the lattice is a triangular lattice.   The light flux controlling member according to claim 1, wherein the lattice is a hexagonal lattice.   The light flux controlling member according to any one of claims 1 to 4, wherein the lattice-shaped convex portion or the lattice-shaped concave portion is integrally formed with the back surface.   The light flux controlling member according to any one of claims 1 to 5, wherein the convex portion of the filament has a R-shaped groove between the filaments. Projections of the striatum, the cross-sectional shape orthogonal to the extending direction a triangular inclination angle is an angle formed between the base and the other side is substantially 55 °, claim 1-6 The light flux controlling member according to any one of the above. A light emitting element that emits light;
The light flux controlling member according to any one of claims 1 to 7 , wherein the light emitting element and the recess are opposed to each other, and the first emission surface is disposed so as to intersect an optical axis of the light emitting element. ,
A light emitting device. The light emitting device according to claim 8 , wherein the light emitting element is a point light source. A light emitting device according to claim 8 or 9 ,
A light diffusing member that diffuses and transmits light emitted from the light emitting device;
A surface light source device. A surface light source device according to claim 1 0,
An illuminated member to which light from the surface light source device is irradiated;
A display device.

Images