JP2018116234A - Luminous flux control member, light-emitting device, surface light source device, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminous flux control member highly stable even in a case where a post-like leg is provided.SOLUTION: A luminous flux control member 1 configured such that light emitted from a light-emitting element is made incident on the inside, the width of the light in an X-axis direction orthogonal to a Z-axis direction parallel to the optical axis of light emitted from the light-emitting element is made wider than that when the light is made incident on, and the light is emitted to the outside, comprises: a leg part 14 projecting toward the light-emitting element from a bottom face 11 facing the light-emitting element, the dimension of the leg in the X-axis direction being longer than the dimension of the leg in a Y-axis direction orthogonal to the Z-axis direction and the X-axis direction; and an overturn prevention structure 15 projecting toward the light-emitting element, at least part of the overturn prevention structure 15 being located outside the leg part 14 in the Y-axis direction.SELECTED DRAWING: Figure 1

Description

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

  As a light source of an edge light type surface light source device, one using a light emitting diode (hereinafter also referred to as “LED”) is known. In such a surface light source device, in order to control the light distribution of the light emitted from the LED, a linear light source body in which the LED and a rod-shaped light flux controlling member are combined may be used (for example, see Patent Document 1). ).

  FIG. 9A is a perspective view showing a configuration of a surface light source element (surface light source device) 110 described in Patent Document 1, and FIG. 9B is a partially enlarged plan view thereof. As shown in FIG. 9, the surface light source element 110 described in Patent Document 1 includes a linear light source 120 and a plate-shaped light guide (light guide plate) 130. The linear light source body 120 is disposed so as to face the side surface of the light guide body 130. The linear light source body 120 includes a plurality of light emitting elements 122 and a translucent resin substrate (light flux controlling member) 124 that controls light emitted from the plurality of light emitting elements 122. On the surface of the translucent resin substrate 124 facing the light guide 130, a plurality of first notches 126 arranged on the optical axes of the light emitting elements 122 and the optical axes of the adjacent light emitting elements 122 are arranged. The second notch portion 128 is formed in each. The light guide 130 guides the light emitted from the linear light source body 120. The side surface 131 of the light guide 130 on the linear light source body 120 side is formed by continuously forming a curved surface 132 that is convex toward the linear light source body 120 and a curved surface 133 that is concave with respect to the linear light source body 120. The whole is formed into a waveform.

  In the surface light source element 110 described in Patent Document 1, light is emitted from the first cutout portion 126 and the second cutout portion 128. That is, the translucent resin substrate 124 has a plurality of light emitting points. At this time, the light emitted from the light emitting element 122 is divided into a direct light group La that is transmitted through the first cutout 126 and an indirect light group Lb that is transmitted through the second cutout 128. . As shown in FIG. 9, in the surface light source element 110 described in Patent Document 1, the emission patterns of the direct light group La and the indirect light group Lb are different. For this reason, in the surface light source element 110 described in Patent Document 1, the distribution of light incident on the light guide 30 is made uniform by forming the shape of the side surface 131 of the light guide 130 into a waveform. The light incident on the light guide 130 is uniformly emitted from the entire top surface of the light guide 130.

JP 2009-295334 A

  In the assembly process of manufacturing the surface light source element 110 of Patent Document 1, the plurality of light emitting elements 122 are mounted on a mounting substrate provided with wiring for supplying power and the like, and further cover the light emitting elements to cover the light transmitting resin substrate. After 124 is arranged on the mounting substrate and the linear light source body 120 is assembled, the linear light source body 120 is arranged on the side of the light guide 130 in the housing. When manufacturing in this way, the translucent resin substrate 124 of the linear light source body 1 is unstable because it is thin and plate-shaped, and may be inclined with respect to the mounting substrate or may fall over. there were.

  Further, in order to prevent heat generation of the light-emitting element 122 and align the translucent resin substrate 124, a columnar leg is provided on the light source side end surface of the translucent resin substrate 124, and the tip of the columnar leg is attached to the mounting substrate. The translucent resin substrate 124 may be fixed by adhering to an adhesive portion. When the columnar legs are provided on the translucent resin substrate 124, the columnar legs can be aligned with the light emitting element 122 by arranging the columnar legs on the bonding portion of the mounting substrate. A gap is provided between the mounting substrate and the translucent resin substrate 124 so that heat generated from the light emitting element 122 can be released. However, the structure fixed by the columnar leg portion makes the translucent resin substrate 124 more unstable, resulting in a decrease in yield in the manufacturing process.

  Further, in the surface light source element 10 described in Patent Document 1, as described above, since the emission patterns of the direct light group La and the indirect light group Lb are different, light is uniformly incident on the light guide 130. For this purpose, the shape of the side surface of the light guide 130 has to be a special shape.

  Accordingly, an object of the present invention is to provide a light flux controlling member having high stability even when a columnar leg is provided. Furthermore, as another object, a light beam control member having a plurality of light emitting points, and the light emission pattern of light emitted from each light emitting point is made the same so that the shape of the light guide plate does not need to be a special shape. It is possible to provide a light flux controlling member that can improve the utilization efficiency of the light emitted from the light emitting element. Another object of the present invention is to provide a light emitting device, a surface light source device, and a display device having the light flux controlling member.

  In order to solve the above-described problems, the light flux controlling member according to the present invention allows light emitted from a light emitting element to enter the inside, and is orthogonal to the Z-axis direction parallel to the optical axis of the light emitted from the light emitting element. A light beam control member that expands the width of light in the axial direction and emits the light outside, and the dimension in the X-axis direction is a dimension in the Y-axis direction orthogonal to the Z-axis direction and the X-axis direction. The bottom surface facing the light emitting element side is longer than the leg part protruding to the light emitting element side, and the fall prevention structure protruding to the light emitting element side, and at least a part of the fall prevention structure is It is arrange | positioned in the position outside the said leg part about the Y-axis direction.

  Further, another light flux controlling member of the present invention allows light emitted from the light emitting element to enter the inside, and performs light in the X axis direction orthogonal to the Z axis direction parallel to the optical axis of the light emitted from the light emitting element. A beam control member that widens the width of the light beam and emits it to the outside. The dimension in the X-axis direction is longer than the dimension in the Y-axis direction perpendicular to the Z-axis direction and the X-axis direction. A leg portion protruding to the light emitting element side and a tipping prevention structure protruding to the light emitting element side on the bottom surface facing the light emitting element side, and the protruding height of the tip of the tipping prevention structure is the leg portion It is characterized by being the same as or lower than the protruding height of the tip of.

  Furthermore, in the light flux controlling member, the light flux controlling member has an emission surface located on the opposite side of the bottom surface, and an incident portion for allowing light emitted from the light emitting element to enter the inside is formed on the bottom surface. The light exiting surface is located on the opposite side of the incident portion in the optical axis direction, partially reflects a part of the light incident from the incident portion, and transmits light to the positive side and the negative side in the X-axis direction. When the light emitting surface concave portion to be distributed is formed and the direction in which light is emitted from the light emitting element is the positive direction of the Z axis, at least the position where the light totally reflected by the light emitting surface concave portion reaches the bottom surface In part, a pair of Z coordinate increasing regions in which the Z coordinate increases as it goes outward in the X axis direction is formed on the positive side and the negative side in the X axis direction, and at least a part of the fall prevention structure includes: Between the pair of Z coordinate increasing regions It is preferably arranged.

  Further, in the light flux controlling member, at least a part of the fall prevention structure may protrude outward in the Y-axis direction, and the fall prevention structure is juxtaposed apart from the Y-axis direction. Alternatively, the fall prevention structure and the leg portion may be provided on a plane portion of a bottom surface parallel to the XY plane. Further, the light flux controlling member preferably has a concave portion formed on the bottom surface and including a bottom concave portion including an incident surface on which at least a part of the light emitted from the light emitting element is incident.

  The light-emitting device of the present invention includes a light-emitting element, and the bundle arranged so that the bottom surface faces the light-emitting element and the Z-axis direction is parallel to an optical axis of light emitted from the light-emitting element. And a control member. Furthermore, the light emitting device may include a mounting substrate on which the light emitting element is mounted, and the leg portion of the light flux controlling member may be fixed to the mounting substrate, and the leg portion is disposed on the mounting substrate. The part may have a substrate recess, and a plurality of the light emitting elements and the light flux controlling member may be arranged side by side in the X-axis direction on the mounting substrate.

  The surface light source device of the present invention includes the light emitting device and a light guide plate that emits light while guiding light from the light emitting device. Moreover, the display apparatus of this invention has the said surface light source device and the to-be-illuminated member with which the light from the said surface light source device is irradiated. According to another aspect of the invention, an electronic apparatus includes the display device as a display unit.

  According to the present invention, the light flux controlling member can be stably fixed to the substrate, and the yield in the assembly process can be improved. In addition, the light beam control member having a plurality of light emitting points, the light emission pattern of the light emitted from each light emitting point can be made the same to the extent that the light guide plate does not need to have a special shape, and from the light emitting element. A light flux controlling member that can improve the utilization efficiency of the emitted light can be provided. Therefore, according to the present invention, it is possible to provide a surface light source device and a display device that have high light utilization efficiency and good productivity in combination with a light guide plate having a simple shape.

It is a figure which shows 1st Embodiment of the light beam control member of this invention, (A) is a top view, (B) is a front view, (C) is a side view, (D) is a bottom view, (E) is a figure. It is a perspective view. It is a figure which shows the light-emitting device of this invention, and is a figure which shows the light-emitting device 4 of this invention, (A) is sectional drawing, (B) is an enlarged view, (C) is a perspective view. It is a figure which shows the surface light source device of this invention, (A) is a top view, (B) is a front view, (C) is a side view, (D) is sectional drawing, (E) is a perspective view. The perspective view which shows the surface light source device which has a some light-emitting device. It is a figure which shows 2nd Embodiment of the light beam control member of this invention, (A) is a top view, (B) is a front view, (C) is a side view, (D) is a bottom view, (E) is a figure. It is a perspective view. It is a figure which shows 3rd Embodiment of the light beam control member of this invention, (A) is a top view, (B) is a front view, (C) is a side view, (D) is a bottom view, (E) is a figure. It is a perspective view. It is a figure which shows a comparative example, (A) is a top view, (B) is a front view, (C) is a side view, (D) is a bottom view, (E) is a perspective view. The figure which shows a shear-force measurement experiment result. (A) is a perspective view which shows the structure of the surface light source element of patent document 1, (B) is the partial enlarged plan view.

[First Embodiment]
FIG. 1 is a view showing a first embodiment of a light flux controlling member 1 of the present invention, (A) is a plan view, (B) is a front view, (C) is a side view, (D) is a bottom view, (E) is a perspective view when viewed from the light emitting element 2 side.

  2A and 2B are views showing a light emitting device 4 of the present invention using the light flux controlling member 1 of the first embodiment, wherein FIG. 2A is a cross-sectional view, FIG. 2B is an enlarged view of the vicinity of the light emitting element 2, and FIG. ) Is a perspective view when viewed from the light guide plate 5 side. The light emitting device 4 of the present invention includes at least the light emitting element 2 and the light flux controlling member 1 and may further include a mounting substrate 3. In the light emitting device 4 of FIG. 2, the light emitting element 2 is mounted on the mounting substrate 3, and the light flux controlling member 1 is fixed so as to cover the light emitting element 2.

  FIG. 3 is a diagram showing a surface light source device 6 of the present invention using the light flux controlling member 1 (light emitting device 4) of the first embodiment. (A) is a plan view, (B) is a front view, (C) is a side view, (D) is a cross-sectional view, and (E) is a perspective view when viewed from the light guide plate 5 side. The surface light source device 6 of the present invention has at least a light emitting device 4 (light flux controlling member 1 and light emitting element 2) and a light guide plate 5, and further, although not shown, a casing, a reflecting plate, and a light diffusing member. You may have. In the surface light source device 6 of FIG. 3, one light emitting device 4 is disposed on one side surface of the long side of the light guide plate 5.

  In this specification, the axis along the optical axis OA of the light emitting element 2 is referred to as “Z axis”, the axis orthogonal to the Z axis is referred to as “X axis”, and the axis orthogonal to the Z axis and X axis is referred to as “Y axis”. The direction parallel to the Z-axis (optical axis) is referred to as “Z-axis direction”, the direction parallel to the X-axis is referred to as “X-axis direction”, and the direction parallel to the Y-axis is referred to as “Y-axis direction”. Further, “outside in the Y-axis direction” means that the distance from the XZ plane passing through the optical axis OA is away in the Y-axis direction, and “outside in the X-axis direction” means in the X-axis direction. Means that the distance from the YZ plane passing through the optical axis OA is long, and when either one is set as the “positive side” in the X-axis direction with reference to the YZ plane passing through the optical axis OA, The other is the “negative side” in the X-axis direction. Further, the light incident on the inside of the light flux controlling member 1 is referred to as “internal incident light”. Further, in the Z-axis direction, the light emitting element 2 side may be referred to as the lower side, and the light guide plate 5 side may be referred to as the upper side.

  The optical control member 1 is a translucent member capable of passing light having a desired wavelength that controls the light distribution of the light emitted from the light emitting element 2. In particular, when used as the surface light source device 6, the optical control member 1 causes the light emitted from the light emitting element 2 to enter the inside, widens the width of the light in the X-axis direction, and emits the light to the outside. For example, the light flux controlling member 1 controls the light distribution so that light emitted from one light emitting element 2 is multipointed. The dimension of the optical control member 1 in the Y-axis direction is preferably about the same as the thickness of the light guide plate 5, and the dimension in the X-axis direction is longer than the dimension in the Y-axis direction. The material of the light flux controlling member 1 is not particularly limited as long as it can pass light having a desired wavelength. For example, the material of the light flux controlling member 1 is light transmissive resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), epoxy resin (EP), silicone resin, or glass.

  As shown in FIG. 1, the optical control member 1 includes a bottom surface 11 facing the light emitting element 2, a light exit surface 12 facing the side opposite to the bottom surface 11 (light guide plate 5 side), and a pair of Y-axis directions. The bottom surface 11 is provided with a leg portion 14 projecting toward the light emitting element 2 and a toppling prevention structure 15 projecting toward the light emitting element 2, and the exit surface 12 includes the exit surface 12. An exit surface recess 17 is formed in the vicinity of a region where 12 and the optical axis intersect. Further, the optical control member 1 may have a bottom surface recess 16 formed on the bottom surface 11.

  The bottom surface 11 faces the light emitting element 2 side of the optical control member 1, and part of the light is emitted from the light emitting element 2 to enter the inside of the optical control member 1. A portion where the light emitted from the light emitting element 2 is incident is defined as an incident portion. The incident portion varies depending on the light distribution characteristics of the light emitting element 2, the arrangement of the light emitting element 2, and the like, but includes at least a position that intersects the optical axis of the bottom surface 11. The bottom surface 11 is provided with the leg portion 14 and the fall prevention structure 15, but the leg portion 14 and the fall prevention structure 15 are formed in a region where the bottom surface 11 has little optical influence. The shape of the bottom surface 11 is extended from the position facing the light emitting element 2 (in this embodiment, the position where the bottom surface recessed portion 16 is formed) to the positive side and the negative side of the X axis. 2 has a Z coordinate increasing region (curved surface portion 11b in FIG. 1) formed so that the Z coordinate increases as the distance from the position facing 2 increases. The shape of the portion connecting such a pair of Z coordinate increasing regions is not particularly limited, and may be a plane (XY plane) perpendicular to the optical axis, an inclined surface, or a curved surface. Alternatively, the shape may be a combination of these. In the aforementioned Z coordinate increasing region, at least part of the light totally reflected by the exit surface recess 17 arrives directly or via the exit surface 12 or the like, and is totally reflected toward the exit surface 12 (a flat surface portion 12a described later). Thus, forming the leg portion 14 and the fall prevention structure 15 at such a position has a great optical effect. Therefore, a region between the pair of Z coordinate increasing regions (for example, the flat surface portion 11a) is selected as a region where the optical influence of the bottom surface 11 is small. In addition, in the case where the incident portion is the flat portion 11a parallel to the XY plane, light having a large emission angle (angle from the optical axis OA) among the light emitted from the light emitting element 2 is reflected on the surface by the flat portion 11a on the bottom surface. Since it becomes easy, there exists a possibility of reducing the utilization efficiency of light. For this reason, it is preferable to provide the bottom surface recessed part 16 in the center part including the optical axis OA of the plane part 11a. Even if the inner surface of the bottom recess 16 is light having a large emission angle from the light emitting element 2, the incident angle with respect to the inner surface can be reduced and can be efficiently incident on the inside of the optical control member 1. When the light emitting element 2 is disposed inside the bottom recess 16, the inner surface of the bottom recess 16 becomes the incident portion. The bottom surface 11 of FIG. 1 has a bottom surface recess 16 formed in the central portion including the optical axis OA, and has a flat surface portion 11a parallel to the XY plane around it, and is continuously outside the flat surface portion 11a in the X-axis direction. The convex curved surface portion 11b extends to the emission surface 12, and the curved surface portion 11b also serves as a side surface in the X-axis direction. The curved surface portion 11b corresponds to a Z coordinate increasing region. The optical control member 1 may be provided with a side surface in the X-axis direction that can be distinguished from the bottom surface 11 (for example, a plane parallel to the YZ plane).

  The emission surface 12 faces the side of the optical control member 1 opposite to the light emitting element 2 and emits the light incident on the inside of the optical control member 1 in the substantially Z-axis direction. The shape of the exit surface 12 is a shape in which the exit surface recess 17 is formed in the vicinity of the region intersecting the optical axis, but the other shapes are not particularly limited, and are a plane (XY plane) perpendicular to the optical axis. Alternatively, it may be an inclined surface, a curved surface, or a combination of these. 1 is a plane portion 12a parallel to the XY plane, and has a shape in which an exit surface recess 17 is formed in a central portion including the optical axis OA.

  The side surfaces 13 positioned on the front and back sides in the Y-axis direction reflect internal incident light traveling in the Y-axis direction toward the exit surface. The shape of the side surface 13 is not particularly limited, and may be a plane (XZ plane) perpendicular to the Y axis, an inclined surface, a curved surface, or a combination of these. But you can. The side surface 13 in FIG. 1 has a shape in which a planar portion 13a parallel to the XZ plane is formed on the light guide plate 5 side and an inclined portion 13b is formed on the light emitting element 2 side. The inclined portion 13b has a function of increasing the proportion of light traveling toward the exit surface 12 with total reflection rather than transmitting the light reaching the inclined portion 13b to the outside with respect to the internally incident light traveling in the Y-axis direction. The light from the element 2 can be used effectively. Instead of the inclined portion, a downwardly convex curved surface portion may be provided.

  The leg portion 14 is for fixing the optical control member 1 to the mounting substrate 3, and is provided so as to protrude from the bottom surface 11 of the optical control member 1 to the optical element 2 side. The leg portion 14 is usually formed of the same material as the optical control member 1 and is integrally formed with the optical control member 1. When the internal incident light enters the leg portion 14, the leg portion 14 is emitted from the side surface of the leg portion 14 or the emission surface 12. In order to disturb the light distribution of the light emitted from the bottom surface 11, the bottom surface 11 is formed in a region having little optical influence. The method for fixing the leg portion 14 to the mounting substrate 3 is not particularly limited. For example, the tip of the leg portion 14 and the surface of the mounting substrate 3 may be bonded with an adhesive, A structure for fitting the tip of the leg portion 14 on the surface may be provided and mechanically fixed. The protruding height to the tip of the leg part 14 (the length from the flat part 11a to the tip of the bottom surface 11) correlates with the width of the gap between the optical control member 1 and the mounting board 3, and is formed on the flat part 11a. When the formed leg portion 14 is fixed to the surface 3 a of the mounting substrate 3, the protruding height of the leg portion 14 matches the width of the gap, and the leg portion 14 is fixed in the substrate recess 31 formed in the mounting substrate 3. In this case, the difference between the protruding height and the depth of the substrate recess 31 is the width of the gap. The leg part 14 of FIG. 1 is a pair of columnar shape, and is provided in the X-axis direction in the symmetrical position centering on an optical axis so that the center of a cylinder may overlap with an X-axis in the plane part 11a of the bottom face 11. .

  The fall prevention structure 15 has a function for preventing the optical control member 1 from tilting or falling after the optical control member 1 is fixed to the mounting substrate 3. Projecting toward the optical element 2 side. The fall prevention structure 15 is also formed integrally with the optical control member 1 with the same material as the optical control member 1. When the internal incident light enters the fall prevention structure 15, the fall prevention structure 15 emits from the side surface of the fall prevention structure 15. In order to disturb the light distribution of the light emitted from the surface 12, the bottom surface 11 is formed in a region having little optical influence. The number of the fall prevention structures 15 is not particularly limited, but it is preferable that the number of the fall prevention structures 15 be an even number since it is preferably provided symmetrically about the optical axis in the X-axis direction.

  Moreover, since the fall prevention structure 15 can support the tilting of the optical control member 1 in the Y axis direction by arranging at least a part of the fall prevention structure 15 at a position outside the leg portion 14 in the Y axis direction. The fall prevention function can be enhanced. Further, the tip of the leg portion 14 needs to be fixed in contact with the surface of the mounting substrate 3, but the tip of the fall prevention structure 15 only needs to support the tipping or tilting, so that the surface of the mounting substrate 3 is not necessarily required. May not be in contact with each other, and may not be fixed (for example, adhered) to the surface of the mounting substrate 3. For this reason, it is preferable that the protruding height of the tip of the fall prevention structure 15 (the length from the flat portion 31a of the bottom surface 11 to the tip) is the same as or lower than the protruding height of the tip of the leg portion 14. In particular, when the substrate recess 31 is provided in the mounting substrate 3 and the leg 14 is fixed in the substrate recess 31, the protruding height of the tip of the leg 14 is higher than the protruding height of the tip of the fall prevention structure 15. There is a need.

  The fall prevention structure 15 shown in FIG. 1 has a pair of quadrangular prisms, and is disposed at a position that is symmetrical about the optical axis in the X-axis direction and that is outside the legs. The dimension of the fall prevention structure 15 in the Y-axis direction is the same width as that between the flat portions 13a of the side surface 13 in the Y-axis direction of the optical control member 1, and the portion in the vicinity of the side surface in the Y-axis direction of the fall prevention structure 15 is a leg portion. 14 is located outside in the Y axis direction. Note that, as in a second embodiment (FIG. 5) described later, at least a part of the fall prevention structure may protrude outward in the Y-axis direction. 1 is slightly lower than the protrusion height of the tip end of the leg portion 14, and the tip end of the leg portion 14 is the substrate recess of the mounting substrate 3, as shown in FIG. The depth of the substrate recess 31 is lowered so that the tip of the fall prevention structure 15 is in contact with the surface of the mounting substrate 3 when in contact with 31.

  In the bottom surface 11, the region where the optical influence is small varies depending on the propagation mechanism of the internally incident light of the light flux controlling member 1, but the light emitted from the optical element 2 (light whose angle with respect to the optical axis is close to 90 degrees) is a light flux. It is a region that is incident on the inside of the control member 1 and is not easily incident on the legs 14 and the fall-preventing structure 15 as internal incident light. For example, in FIG. 1, a flat portion disposed between the Z coordinate increasing regions It is preferable to provide the leg part 14 and the fall prevention structure 15 in 11a. Further, the internal incident light may travel downward due to reflection on the exit surface 12 or the like, but it is more preferable to set the region where the downward internal incident light is small. When the total amount of light emitted from the light emitting element 2 is 100%, the region where the amount of light reaching the region is 7% or less can be said to be a region with little internal incident light. As a result of simulating the amount of light emitted to the exit surface 12 and the amount of light incident on the flat portion 11a of the bottom surface 11 for the light flux controlling member 1 in FIG. The amount of incident light was 78.7%, and the amount of light incident on the flat surface portion 11a was 3.4%. In this way, by simulating the light amount, it is possible to specify a region on the bottom surface 11 that is less optically affected.

  The bottom surface recess 16 is formed in the vicinity of the region where the bottom surface 11 and the optical axis intersect, and allows the light emitted from the optical element 2 to be efficiently incident. The inner upper surface of the bottom recess 16 serves as an incident surface on which at least part of the light emitted from the optical element 2 is incident. If the light emitting surface of the optical element 2 is positioned so as to be located above the flat surface portion 11a of the bottom surface 11 in the bottom surface recess 16, the light emitted from the optical element 2 in the X-axis direction (the angle with respect to the optical axis is 90 degrees). Is incident on the inner side surface of the bottom concave portion 16 and passes as an internal incident light above the plane portion 11a, so that the leg portion 14 provided on the plane portion 11a and the fall prevention structure 15 are optically coupled. The influence can be reduced, and for example, the leg portions 14 and the fall-preventing structure 15 can be easily arranged other than the flat portion 11 a of the bottom surface 11. Furthermore, by making the inner surface of the bottom recess 16 a curved surface or an inclined surface, it is possible to provide a light beam control function. 1 has a substantially rectangular parallelepiped shape.

  The exit surface recess 17 is provided in the center of the exit surface 12, and at least a part of the light incident near the optical axis in the vicinity of the optical axis of the internal incident light is close to 0 degrees on the positive side and the negative side in the X-axis direction. A pair of side surfaces 17a for total reflection toward the surface. In FIG. 1, the pair of side surfaces 17 a are inclined surfaces that are arranged in the X-axis direction with the optical axis as the center, and the intersection with the optical axis is parallel to the Y-axis that is arranged closest to the light emitting element. Note that the total reflection surfaces (the pair of side surfaces 17a in FIG. 1) formed by the exit surface recesses 17 need only be designed so that the light emitted from the light emission center of the optical element 2 can be efficiently totally reflected, as shown in FIG. Thus, the light radiate | emitted outside from the side surface 17a may arise.

[Light emitting device]
As shown in FIG. 2, the light emitting device 4 has the light emitting element 2 disposed so that the optical axis OA of the light emitted onto the mounting substrate 3 is substantially parallel to the normal to the surface of the mounting substrate 3, and further emits light. The light flux controlling member 1 is fixed so as to cover the element 2 and so that the center of the bottom surface 11 of the light flux controlling member 1 (or the center of the bottom concave portion 16) overlaps the optical axis. The numbers of the optical control member 1 and the light emitting elements 2 arranged on the mounting substrate 3 are not particularly limited. The light-emitting device 4 may be a light-emitting device 4 having a plurality of light sources by disposing a plurality of optical control members 1 and light-emitting elements 2 on a mounting substrate 3, or as shown in FIG. The optical control member 1 and the light emitting element 2 may be disposed, and the light source 4 may have one light source.

  The light emitting element 2 is a light source of the light emitting device 4 (and the surface light source device 6 and the display device). As the light emitting element 2, an LED, a light bulb, a xenon lamp, a semiconductor laser, an organic EL element, a micro fluorescent tube, or the like can be adopted. Although the light emitting element 2 is not specifically limited, For example, it is light emitting diodes (LED), such as a white light emitting diode.

  The mounting substrate 3 mounts the light emitting element 2 and the light control member 1 is fixed. Furthermore, it is preferable that the mounting substrate 3 has a bonding substrate recess 31 for bonding the leg portion 14 of the light flux controlling member 1. Further, the mounting substrate 3 may be provided with wiring for supplying power or the like to the light emitting element 2. The shape of the mounting substrate 3 is preferably elongated in the X-axis direction like the light control member 1 and is preferably arranged as shown in FIG. 2 with the X-axis direction of the light control member 1 aligned.

  In the light emitting device 4 shown in FIG. 2A, the emission surface of the light emitting element 1 is disposed to face the bottom surface recess 16 in the bottom surface 11 of the light control member 1, and most of the light emitted from the light emitting element 1 is The light enters the light control member 1 through the inner surface of the bottom recess 16 of the light control member 1. Of the internal incident light, part of the light near the optical axis that travels to the exit surface recess 17 is internally reflected by the side surface 17a of the exit surface recess 17 to the positive side and the negative side in the X-axis direction, and part of the light is transmitted outside To exit. The light reflected to the positive side and the negative side in the X-axis direction is internally reflected by the emission surface 12, and is internally reflected to the emission surface 12 side by the curved surface portion 11b of the bottom surface 11 arranged on the outer side in the X-axis direction. To the outside. At this time, the position where the light is emitted from the exit surface 12 after being internally reflected by the curved surface portion 11b is like a light emitting point.

  Further, a part of the internal incident light that is directed outward in the X-axis direction from the exit surface recess 17 is partially reflected internally by the exit surface 12 and partially transmitted to exit to the outside. The internally reflected light is reflected or transmitted by the flat surface portion 11a or the curved surface portion 11b of the bottom surface 11 and is emitted to the outside. As described above, a part of the light traveling outward in the X-axis direction from the exit surface concave portion 17 may be irradiated to the flat portion 11 a of the bottom surface 11, and may be disturbed by the leg portion 14 or the fall prevention structure 15. There is sex. For this reason, it is possible to widen the area | region with little optical influence in the bottom face 11 by making the output surface recessed part 17 wide.

  Note that the light distribution state of the internal incident light can be controlled by changing the position of the light emitting element 2 with respect to the bottom recess 16. Specifically, for example, by narrowing the distance between the bottom surface recess 16 and the light emitting element 2, the amount of light incident on the top surface of the bottom surface recess 16 out of the light emitted from the light emitting element 2 can be increased. . Further, for example, by widening the gap between the bottom surface recess 16 and the light emitting element 2, the amount of light incident on the side surface of the bottom surface recess 16 among the light emitted from the light emitting element 2 can be increased.

[Surface light source device, etc.]
As shown in FIG. 3, the surface light source device 6 is configured such that the emission surface 12 of the light flux controlling member 1 in the light emitting device 4 faces the side surface of the light guide plate 5 and guides the light emitted from the light emitting device 4 from the side surface of the light guide plate 5. The light is made incident inside the optical plate 5. The surface light source device 6 is used, for example, for a backlight of a display device, a lighting device, or the like. One light emitting device 4 may be disposed on one side surface of the light guide plate 5, or a plurality of light emitting devices 4 may be disposed. Further, a plurality of light emitting devices 4 may be arranged on a plurality of side surfaces of the light guide plate 5. The surface light source device 6 includes a housing (not shown) that houses the light guide plate 5, the light emitting device 4, etc., a reflection plate (not shown) that reflects light emitted outside the surface of the light guide plate 5, You may have the light-diffusion member (not shown) which diffuses the light radiate | emitted on the surface.

  The light guide plate 5 guides the light emitted from the light flux controlling member 1 and emits it from the front surface and / or the back surface. The planar view shape of the light guide plate 5 preferably corresponds to the shape of the display area of the irradiated member (for example, a liquid crystal panel). Further, from the viewpoint of increasing the utilization efficiency of the light emitted from the light beam control member 1, the thickness of the light guide plate 5 is preferably thicker than the length of the light emission surface 12 of the light beam control member 1 in the Y-axis direction. The light emitted from the front surface or the back surface of the light guide plate 5 becomes planar light traveling in the Y-axis direction. The material of the light guide plate 5 is a light transmissive resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), epoxy resin (EP), silicone resin, or glass. The material of the light guide plate 5 may be the same material as the light flux controlling member 1 or a different material.

  The housing is a housing body having a shape in which at least a part of one surface is opened for housing the light emitting device, the light guide plate, and the reflection plate therein. The housing is formed with an opening serving as a light emitting region, and the opening is closed by a light diffusing member. The opening is usually rectangular, but may have other shapes, and the size of the opening corresponds to the size of the light emitting region (light emitting surface) formed in the light diffusing member. The housing is made of, for example, a resin such as polymethyl methacrylate (PMMA) or polycarbonate (PC), or a metal such as stainless steel or aluminum.

  The reflection plate is provided on at least a part of the inner surface of the region other than the light emitting region, and is disposed, for example, on the bottom or side surface of the housing. The reflection plate reflects light emitted from the back surface, side surface, and the like of the light guide plate, and light emitted from a surface other than the light emission surface of the light emitting device, and directs the light toward the light diffusion member via the light guide plate. The reflector is made of, for example, a metal such as stainless steel or aluminum. Moreover, you may give the function of a reflecting plate by making the inner surface of a housing | casing into a reflective surface.

  The light diffusing member is disposed on the light exit side of the light guide plate 5 and is disposed, for example, so as to close the opening of the housing. The light diffusing member is a plate-like or film-like member having light diffusibility, and allows light emitted from the light guide plate to pass through while diffusing. Usually, the light diffusing member is approximately the same size as an irradiated member such as a liquid crystal panel. For example, the light diffusing member is made of a light transmissive resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), styrene / methyl methacrylate copolymer resin (MS). In order to impart light diffusibility to the light diffusion member, fine irregularities are formed on the surface, or light diffusers such as beads are dispersed inside the light diffusion member.

  In the surface light source device 6 according to the present embodiment, light emitted from one light emitting element 2 is divided by the corresponding light flux control member 1, and light is emitted from a plurality of light emitting points of one light flux control member 1. Is done. Light emitted from each light emitting point of the light emitting device 4 enters the light guide plate 5 at the side surface (incident surface) of the light guide plate 5. At this time, the light emitting points of the light emitting device 4 are substantially equally spaced, and the light amount and the emission pattern of the light emitted from each light emitting point are also similar. Therefore, even if the shape of the incident surface of the light guide plate 5 is a flat surface, light enters the light guide plate 5 almost uniformly. The light incident on the light guide plate 5 is gradually emitted from the front surface and / or the back surface while traveling through the light guide plate 5. The light emitted from the back surface of the light guide plate 5 is reflected toward the back surface of the light guide plate 5 by a reflection plate (not shown), passes through the light guide plate 5 and travels toward the light diffusion member. The light emitted from the surface of the light guide plate 5 is also directed to the light diffusing member. The light that has reached the light diffusing member passes through the light diffusing member while being diffused by the light diffusing member.

  FIG. 4 shows an embodiment of a surface light source device 6 in which a plurality of light flux controlling members 1 and light emitting elements 2 are arranged on one mounting substrate 3. The mounting board 3 has a rectangular shape extending in the X-axis direction, and three light flux controlling members 1 and three light emitting elements 2 are arranged on the mounting board 3 in the longitudinal direction. The light guide plate 5 is disposed so that the side surface of the light guide plate 5 faces the light exit surface 12 side of the three light flux control members 1. In FIG. 4, a gap is provided between the adjacent light flux control members 1, but the light emitted from the light flux control member 1 is made uniform according to the light distribution characteristics of the emitted light from the light flux control member 1. It is preferable to adjust the width of the gap. The gap may not be provided, or a plurality of light flux control members 1 may be connected at the end in the X-axis direction so as to be a light flux control member 1 common to the plurality of light emitting elements 2.

  The display device of the present invention includes the surface light source device 6 and a member to be illuminated to which light from the surface light source device 6 is irradiated. The illuminated member is, for example, a liquid crystal display panel, an electric signboard, an internally illuminated sign, or the like. The electronic apparatus of the present invention includes the display device as a display unit. Examples of electronic devices include mobile phones, display devices for car navigation systems, PDAs (Personal Digital Assistants), mobile computers, digital cameras, digital video cameras, in-vehicle devices, audio devices, portable game machines, traffic lights, and the like. However, it is not limited to these.

[Second Embodiment]
FIG. 5 is a view showing a second embodiment of the light flux controlling member 1 of the present invention, (A) is a plan view, (B) is a front view, (C) is a side view, (D) is a bottom view, (E) is a perspective view when viewed from the light emitting element 2 side. The light flux controlling member 1 in FIG. 5 differs from the light flux controlling member in FIG. The overturning prevention structure 25 of the light flux controlling member 1 in FIG. 5 is apparent from FIGS. 5A, 5 </ b> C, and 4 </ b> D, but protrudes outward in the Y-axis direction from the flat portion 13 a of the side surface 13. It has a protrusion 25a. The protrusion 25a can further prevent the light flux controlling member 1 from tilting or falling over in the Y-axis direction. In order to make the fall prevention function more effective, the protruding portions 25 a may be provided so as to protrude from both side surfaces 13 of the light flux controlling member 1. However, from the viewpoint of assembling the light beam control member 1 as the surface light source device 6, one of the side surfaces of the light beam control member 1 is the bottom of the surface light source device 6, and thus the protruding portion 25 a is provided on only one of them. The other, as the bottom of the surface light source device 6, is preferably not provided with a protruding portion, and more preferably the same plane as the flat portion 13 a of the side surface 13.

[Third Embodiment]
FIG. 6 is a view showing a third embodiment of the light flux controlling member 1 of the present invention, where (A) is a plan view, (B) is a front view, (C) is a side view, (D) is a bottom view, (E) is a perspective view when viewed from the light emitting element 2 side. The light flux controlling member 1 in FIG. 6 differs from the light flux controlling member in FIG. The fall prevention structure 35 of the light flux controlling member 1 in FIG. 6 is apparent from FIG. 6D, but a pair of two fall prevention structures 35 that are spaced apart from each other in the Y axis direction are provided in the X axis direction. As a whole, four fall prevention structures 35 are provided. Each fall prevention structure 35 has an outer side surface in the Y-axis direction that is the same plane as the flat portion 13 a of the side surface 13. Dispersion of light due to the overturning prevention structure 35 can be reduced by separating and juxtaposing them in the Y-axis direction. Furthermore, according to the result of the experiment, it was possible to further prevent the light flux controlling member 1 from being inclined or toppled over in the Y-axis direction. 6 may also be provided with a protruding portion that protrudes outward in the Y-axis direction relative to the flat surface portion 13a of the side surface 13.

[Comparative example]
FIG. 7 is a diagram showing a light flux controlling member 41 that does not have a fall prevention structure as a comparative example, where (A) is a plan view, (B) is a front view, (C) is a side view, and (D). Is a bottom view, and (E) is a perspective view when viewed from the light emitting element 2 side. The light flux control member 41 in FIG. 7 differs from the light flux control member in FIGS. 1 to 6 only in that it does not have a fall prevention structure.

[Shearing force measurement experiment]
FIG. 8 shows a mounting board for the legs of the optical control members of the first embodiment (FIG. 1), the second embodiment (FIG. 5), the third embodiment (FIG. 6), and the comparative example (FIG. 7). It is the experimental result which measured the shear force, after fixing with an adhesive agent on the top. In the experiment, two samples were prepared and measured. The adhesive used was LOCTITE 3280, and each leg was adhered to the substrate recess of the mounting substrate with about 0.7 mg (one drop) of adhesive, and cured on a hot plate at 80 ° C. for 5 minutes to obtain an experimental sample. . Note that the fall prevention structure is not bonded to the mounting substrate. A load was applied from the Y-axis direction with the mounting substrate of this sample fixed. Shear force was evaluated by the load when the optical control member was detached from the mounting substrate. In the comparative example, it was 16.28N and 17.42N, and the average was 16.85N, but in the first embodiment, it was 21.80N and 25.08N, which increased to an average of 23.44N. In 2nd Embodiment, they were 44.65N and 33.81N, and increased large on average to 39.23N. In 3rd Embodiment, it was 30.25N and 30.31N, and increased on average 30.29N.

  As described above, it was confirmed that by providing the fall prevention structure, the optical control member became strong against the load in the Y-axis direction and was difficult to fall. In particular, as in the second embodiment, the one provided with the protruding portion in the Y-axis direction showed a shearing force twice or more that of the comparative example.

DESCRIPTION OF SYMBOLS 1 Light flux control member 2 Light emitting element 3 Mounting board 4 Light-emitting device 5 Light guide plate 6 Surface light source device 11 Bottom surface 12 Outgoing surface 13 Side surface 14 Leg part 15 Fall prevention structure 16 Bottom surface recessed part 17 Outgoing surface recessed part

Claims (14)

Light emitted from the light emitting element is incident on the inside, and the width of the light in the X-axis direction perpendicular to the Z-axis direction parallel to the optical axis of the light emitted from the light emitting element is made wider than that at the time of incidence and emitted to the outside. A light flux controlling member
The dimension in the X-axis direction is longer than the dimension in the Y-axis direction orthogonal to the Z-axis direction and the X-axis direction,
The bottom surface facing the light emitting element side has a leg portion protruding to the light emitting element side, and a fall prevention structure protruding to the light emitting element side,
At least a part of the fall prevention structure is arranged at a position outside the leg in the Y-axis direction. Light emitted from the light emitting element is incident on the inside, and the width of the light in the X-axis direction perpendicular to the Z-axis direction parallel to the optical axis of the light emitted from the light emitting element is made wider than that at the time of incidence and emitted to the outside. A light flux controlling member
The dimension in the X-axis direction is longer than the dimension in the Y-axis direction orthogonal to the Z-axis direction and the X-axis direction,
The bottom surface facing the light emitting element side has a leg portion protruding to the light emitting element side, and a fall prevention structure protruding to the light emitting element side,
The light flux controlling member, wherein a protrusion height of the tip of the fall prevention structure is the same as or lower than a protrusion height of the tip of the leg. The light flux controlling member has an exit surface located on the side opposite to the bottom surface,
The bottom surface is formed with an incident portion for making the light emitted from the light emitting element incident inside,
The exit surface is located on the opposite side of the incident portion in the optical axis direction, and partially reflects the light incident from the incident portion and distributes the light to the positive side and the negative side in the X-axis direction. A concave surface is formed,
When the direction in which light is emitted from the light emitting element is the positive direction of the Z axis,
On the bottom surface, at least a part of the position where the light totally reflected by the exit surface concave portion reaches is a Z coordinate increasing region in which the Z coordinate increases in the X-axis direction in the X-axis direction. A pair is formed on the positive side and the negative side,
The light flux controlling member according to claim 1, wherein at least a part of the fall prevention structure is disposed between the pair of Z coordinate increasing regions.   4. The light flux controlling member according to claim 1, wherein at least a part of the fall prevention structure protrudes outward in the Y-axis direction. 5.   5. The light flux controlling member according to claim 1, wherein the fall prevention structure is juxtaposed and spaced apart in the Y-axis direction.   The light flux controlling member according to any one of claims 1 to 5, wherein the fall prevention structure and the leg portion are provided on a flat surface portion of a bottom surface parallel to the XY plane.   The concave portion formed in the bottom surface, comprising a bottom surface concave portion including an incident surface for allowing at least a part of light emitted from the light emitting element to enter the inside. The light flux controlling member according to item. A light emitting element;
The light flux control according to any one of claims 1 to 7, wherein the bottom surface faces the light emitting element, and the Z-axis direction is disposed in parallel with an optical axis of light emitted from the light emitting element. Members,
A light emitting device comprising: A mounting substrate on which the light emitting element is mounted;
The light emitting device according to claim 8, wherein the leg portion of the light flux controlling member is fixed to the mounting substrate.   The light emitting device according to claim 9, wherein the mounting substrate has a substrate recess in a portion where the leg portion is disposed.   11. The light emitting device according to claim 8, wherein a plurality of the light emitting elements and the light flux controlling member are arranged side by side in the X-axis direction on the mounting substrate. A light emitting device according to any one of claims 8 to 11,
A light guide plate that emits light while guiding light from the light emitting device;
A surface light source device comprising: A surface light source device according to claim 12,
An illuminated member to which light from the surface light source device is irradiated;
A display device comprising:
A display device comprising:   An electronic apparatus comprising the display device according to claim 13 as a display unit.