JP2018125079A - Light emitting device, surface light source device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device in which deterioration of optical characteristics of a luminous flux control member caused by attachment of an adhesive agent which has moved from the periphery of a convex part of the luminous flux control member to an optical surface can be suppressed.SOLUTION: A light emitting device includes a base body, a light emitting element and a luminous flux control member. The luminous flux control member has a first optical surface, a second optical surface, a rear surface and a convex part. The rear surface comes into contact with one surface of the base body. The convex part is arranged on the rear side of the luminous flux control member, and fitted in a first concave part so that a gap is generated between itself and an inner surface of the first concave part formed on the base body. On the rear surface, a second concave part is formed which surrounds a base end part of the convex part so as to communicate with the gap and which opens to the outside in a radial direction of the luminous flux control member and to the rear side of the luminous flux control member. The luminous flux control member is fixed to the base body at least via a cured material of an adhesive agent filled in the gap.SELECTED DRAWING: Figure 1

Description

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

  A display device such as a liquid crystal display has a surface light source device including a light emitting device as a backlight. The light emitting device includes, for example, a base, a light emitting element held on the base, and a light flux controlling member that is disposed on the light emitting element and controls the light distribution of light emitted from the light emitting element. (For example, refer to Patent Document 1).

  The light flux controlling member described in Patent Document 1 has a convex portion disposed on the back surface thereof. The shape of the tip of the convex portion is a spherical crown shape convex toward the base. The light emitting device can be manufactured by disposing a light flux controlling member on the base and curing the adhesive in a state where the adhesive is applied at a position on the base where the convex portion is disposed. Since the shape of the convex portion is a spherical crown shape, the adhesive is easily pushed around the convex portion when the light flux controlling member is disposed on the base. For this reason, the light flux controlling member can be appropriately disposed on the substrate in a state where the tip of the convex portion is in contact with the surface of the base. As a result, in the light emitting device described in Patent Document 1, it is possible to suppress the light flux controlling member from being fixed in a state of being separated from the surface of the substrate by the adhesive.

Japanese Patent Laying-Open No. 2015-041437

  As another type of light emitting device, for example, a light emitting device in which a light flux controlling member is fixed on a substrate so that the back surface of the light flux controlling member and the surface of the substrate are in contact with each other is also known. In such a light emitting device, in order to position the light flux controlling member, a fitting concave portion is formed on one surface of the base, and the convex portion of the light flux controlling member may be fitted into the concave portion. In such a light emitting device in which the back surface of the light beam control member and the surface of the substrate are in contact with each other, when the light beam control member described in Patent Document 1 is adopted as the light beam control member, the adhesion is pushed to the outside of the convex portion. There is a possibility that the agent enters the gap between the back surface of the light flux controlling member and the surface of the substrate and reaches the optical surface of the light flux controlling member. Therefore, in the conventional light emitting device, the optical characteristics of the light flux controlling member deteriorate due to the adhesion of the adhesive that has moved from the periphery of the convex portion through the gap between the back surface and the surface of the substrate to the optical surface. There is a fear.

  An object of the present invention is to provide a light emitting device capable of suppressing a decrease in optical characteristics of a light flux controlling member due to adhesion of an adhesive that has moved from the vicinity of a convex portion of the light flux controlling member to an optical surface, and the light emitting device. A surface light source device and a display device are provided.

  The light-emitting device according to the present invention includes a base having a first recess formed on one surface, a light-emitting element held on the base, the base and the light-emitting element, and A light flux control member for controlling the light distribution of the emitted light, and the light flux control member is disposed on the back side of the light flux control member, and transmits the light emitted from the light emitting element to the inside of the light flux control member. A first optical surface for incidence on the first optical surface, and a first optical surface disposed on the front side thereof, abutting on the second optical surface for transmitting or reflecting the light incident on the first optical surface and the one surface of the substrate And between the back surface extending along the direction orthogonal to the central axis of the light flux controlling member outside the first optical surface and the inner surface of the first recess Fits into the first recess so that there is a gap in the A convex portion that surrounds a base end portion of the convex portion so as to communicate with the gap, and a radially outer side of the light flux controlling member and a back side of the light flux controlling member. The light flux controlling member is fixed to the base body through a cured product of an adhesive filled in at least the gap.

  The surface light source device according to the present invention includes the light emitting device according to the present invention and a light diffusing member that diffuses the light emitted from the light emitting device while transmitting the light.

  The display device according to the present invention includes the surface light source device according to the present invention and an irradiated member that is irradiated with light emitted from the surface light source device.

  According to the present invention, it is possible to suppress a decrease in optical characteristics of the light flux controlling member due to adhesion of the adhesive that has moved from the vicinity of the convex portion of the light flux controlling member to the optical surface.

FIG. 1 is a cross-sectional view illustrating a configuration of a display device according to an embodiment. 2A to 2D are diagrams showing the configuration of the light flux controlling member according to the embodiment. 3A and 3B are schematic views showing a process of fixing the light flux controlling member to the base. 4A to 4C are diagrams illustrating a configuration of a light flux controlling member according to Modifications 1 to 3 of the embodiment.

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

(Configuration of display device)
FIG. 1 is a cross-sectional view illustrating a configuration of a display device 100 according to the present embodiment. As shown in FIG. 1, the display device 100 includes a surface light source device 110 and an irradiated member 120.

  The surface light source device 110 is a light source of the display device 100. The irradiated member 120 is irradiated with light emitted from the surface light source device 110. An example of the irradiated member 120 includes a liquid crystal panel.

(Configuration of surface light source device)
As shown in FIG. 1, the surface light source device 110 includes a substrate 130, a light emitting device 140, and a light diffusing member 150.

  The substrate 130 holds the light emitting device 140. The substrate 130 is not particularly limited as long as it can hold the light emitting device 140. Examples of the substrate 130 include a glass composite substrate and a glass epoxy substrate.

  The light emitting device 140 is a light source of the surface light source device 110. Details of the light emitting device 140 will be described later.

  The light diffusion member 150 diffuses the light emitted from the light emitting device 140 while transmitting the light. The light diffusing member 150 is not particularly limited as long as it has the function. Examples of the light diffusing member 150 include a transparent plate member subjected to a light diffusion process (for example, a roughening process) and a transparent plate member mixed with scatterers such as beads. Examples of the material of the plate-like member include polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), and methyl methacrylate-styrene copolymer resin (MS). Examples of the material of the beads include glass and acrylic resin.

(Configuration of light emitting device)
As shown in FIG. 1, the light emitting device 140 includes a base body 160, a light emitting element 170, and a light flux controlling member 180. The light flux controlling member 180 is fixed to the base body 160 via the cured adhesive 10. In the present specification, the “adhesive” means both the adhesive 10 ′ in a state before curing and the adhesive (cured product) 10 in a state after curing.

  The base body 160 holds the light emitting element 170. The shape of the substrate 160 is not particularly limited as long as the light emitting element 170 can be held. In the present embodiment, the shape of the base body 160 is a substantially rectangular parallelepiped shape. As the substrate 160, a known substrate used as a package substrate for an LED package can be used. In the present embodiment, a light emitting element recess 161 and three first recesses 162 are formed on one surface (top surface) of the base body 160.

  The light emitting element recess 161 is formed at the center of the top surface of the base 160. A light emitting element 170 is disposed inside the light emitting element recess 161. The shape and size of the light emitting element recess 161 are not particularly limited as long as the light emitting element 170 is disposed inside the light emitting element recess 161 and does not interfere with the light emitted from the light emitting element 170. Moreover, it is preferable that the inner surface of the light emitting element recess 161 is a reflective surface having a high light reflectance.

  The first recess 162 is formed outside the light emitting element recess 161 on the top surface of the base 160. Although details will be described later, a convex portion 184 (described later) of the light flux controlling member 180 is fitted inside the first concave portion 162. A gap is formed between the inner surface of the first concave portion 162 and the convex portion 184, and the adhesive 10 is filled in the gap. In the present embodiment, a gap is formed between the inner side surface of the first concave portion 162 and the side surface of the convex portion 184.

  The position, shape, size, and number of the first recesses 162 can be appropriately changed according to the position, shape, size, and number of the convex portions 184 of the light flux controlling member 180. The position, shape, size, and number of the first concave portions 162 correspond to the position, shape, size, and number of the convex portions 184. Examples of the shape of the first recess 162 include a cylindrical shape and a polygonal column shape. The shape of the tip portion of the first recess 162 may be a spherical crown shape. In the present embodiment, the first recess 162 has a cylindrical shape. The size of the first concave portion 162 is larger than the convex portion 184 by the amount corresponding to the gap.

  The light emitting element 170 is a light source of the light emitting device 140. The light emitting element 170 is held on the base body 160. More specifically, the light emitting element 170 is accommodated in the light emitting element recess 161 of the base 160. The light emitting element 170 may be sealed with a resin filled in the light emitting element recess 161. Examples of the light emitting element 170 include a light emitting diode (LED). The base 160 and the light emitting element 170 may be integrated as an LED package.

  2A to 2D are diagrams showing a configuration of light flux controlling member 180 according to the present embodiment. 2A is a plan view of the light flux controlling member 180, FIG. 2B is a bottom view, FIG. 2C is a front view, and FIG. 2D is a cross-sectional view taken along line DD in FIG. 2A.

  The light flux controlling member 180 is disposed on the base body 160 and the light emitting element 170 and controls the light distribution of the light emitted from the light emitting element 170. In the present embodiment, light flux controlling member 180 is a diffusing lens. That is, in the light beam control member 180, the angle of the light emitted to the outside of the light beam control member 180 with respect to the optical axis OA of the light emitting element 170 is larger than the light incident on the light beam control member 180. Control the traveling direction of light. In the present specification, “optical axis OA of the light emitting element” means a light beam at the center of a three-dimensionally emitted light beam from the light emitting element 170.

  As shown in FIGS. 2A to 2D, the light flux controlling member 180 has an incident surface 181, a back surface 182, an exit surface 183, a convex portion 184, and a flange 185. An incident surface recess 1821 is formed at the center of the back surface 182 (the surface on the light emitting element 170 side). Three second recesses 1822 that are spaced apart from each other are formed on the outer edge of the back surface 182.

  Note that the shapes of the incident surface 181 and the exit surface 183 of the light flux controlling member 180 are both rotationally symmetric, and their rotational axes substantially match. Hereinafter, the rotation axes of the entrance surface 181 and the exit surface 183 are referred to as “center axis CA of the light flux controlling member”.

  As shown in FIG. 1, the light flux controlling member 180 is arranged such that the central axis CA substantially coincides with the optical axis OA of the light emitting element 170. The back surface 182 of the light flux controlling member 180 and the top surface of the base 160 are in contact with each other, and the incident surface 181 of the light flux controlling member 180 and the light emitting surface of the light emitting element 170 are opposed to each other.

  The incident surface 181 is disposed on the back side of the light flux controlling member 180. The incident surface 181 is an optical surface that allows the light emitted from the light emitting element 170 to enter the light flux controlling member 180. The incident surface 181 constitutes the inner surface of the incident surface recess 1821. The shape of the incident surface 181 can be appropriately set according to the desired light distribution. In the present embodiment, the shape of the incident surface 181 is the same as that of a part of the surface of an ellipsoid formed so that its major axis is along the central axis CA of the light flux controlling member 180. Thereby, the incident surface 181 refracts the traveling direction of the light emitted from the light emitting element 170 so that the angle with respect to the optical axis OA becomes larger, and the light emitted from the light emitting element 170 of the light flux controlling member 180. It can be incident inside.

  The back surface 182 is disposed on the back side of the light flux controlling member 180 and extends along the direction perpendicular to the central axis CA of the light flux controlling member 180 outside the incident surface 181. In the present embodiment, back surface 182 is a plane perpendicular to central axis CA. The back surface 182 is in contact with the top surface of the base body 160. This seals the space (in this embodiment, the light emitting element concave portion 161 and the incident surface concave portion 1821) formed between the base 160 and the light flux controlling member 180 inside the inner edge of the back surface 182. Intrusion of foreign matter such as dust can be suppressed.

  The exit surface 183 is disposed on the front side of the light flux controlling member 180. The exit surface 183 is an optical surface that transmits the light incident on the inside of the light flux controlling member 180 through the incident surface 181 and emits the light to the outside of the light flux controlling member 180. The shape of the emission surface 183 can be appropriately set according to the desired light distribution.

  The emission surface 183 includes a first emission surface 183a arranged over a predetermined range centered on the central axis CA, and a second emission surface 183b arranged continuously around the first emission surface 183a. And a third emission surface 183c arranged continuously around the second emission surface 183b (see FIG. 2D). In the present embodiment, the third emission surface 183c connects the outer edge of the second emission surface 183b and the inner edge of the top surface of the flange 185.

  The first emission surface 183 a is a smooth curved surface that is convex on the back side of the light flux controlling member 180. The second exit surface 183b is a smooth curved surface that is located on the front side of the light flux controlling member 180 and is located around the first exit surface 183a. The third exit surface 183c is a smooth curved surface convex to the front side of the light flux controlling member 180 located around the second exit surface 183b. The shapes of the second emission surface 183b and the third emission surface 183c are annular shapes.

  The convex portion 184 is disposed on the back side of the light flux controlling member 180 and is fitted in the first concave portion 162 so that a gap is formed between the convex portion 184 and the inner surface of the first concave portion 162 (see FIG. 1). ). The convex portion 184 protrudes from the back surface 182 of the light flux controlling member 180 toward the back side. By fitting the convex portion 184 into the first concave portion 162, the position of the light flux controlling member 180 can be determined appropriately and easily. The number and position of the convex portions 184 are not particularly limited as long as the light flux controlling member 180 can be appropriately positioned. In the present embodiment, the number of convex portions 184 is three. The three convex portions 184 are arranged on the virtual circle along the outer periphery of the light flux controlling member 180 so as to be spaced apart from each other at equal intervals.

  The shape and size of the convex portion 184 are not particularly limited as long as a gap having an intended size is formed between the inner surface of the first concave portion 162. In the present embodiment, the shape of the convex portion 184 is a cylindrical shape like the shape of the first concave portion 162, and the outer diameter of the convex portion 184 is smaller than the inner diameter of the first concave portion 162 by the amount corresponding to the gap. .

  The gap extends along the fitting direction of the convex portion 184 (the depth direction of the second concave portion 1822). The shape and size of the gap can be appropriately adjusted within a range in which the effect of the present embodiment can be obtained. The said clearance gap may be arrange | positioned over the whole circumferential direction of the convex part 184, and may be arrange | positioned over a part of circumferential direction of the convex part 184 (refer the modification 1 mentioned later). In the present embodiment, the gap is arranged over the entire circumferential direction of the convex portion 184.

  The flange 185 is disposed between the emission surface 183 and the back surface 182 at the outer edge of the light flux controlling member 180. Although details will be described later, it is preferable that the light flux controlling member 180 has a flange 185 from the viewpoint of suppressing the adhesion of the adhesive 10 to the emission surface 183 when the light emitting device 140 is manufactured. The shape and size of the flange 185 are not particularly limited, and can be appropriately adjusted as necessary. In the present embodiment, the flange 185 has an annular shape.

  As described above, the second recess 1822 is formed on the back surface 182. The second concave portion 1822 surrounds the base end portion of the convex portion 184 so as to communicate with the gap, and is open to the outside in the radial direction of the light flux controlling member 180 and the back side of the light flux controlling member 180. In the present embodiment, second recess 1822 opens only on the outer edge of flange 185 and the surface of back surface 182. That is, the second recess 1822 is not opened in the light emitting element recess 1821. In the light emitting device 140, the gap between the inner surface of the first concave portion 162 and the convex portion 184 communicates with the outside via the second concave portion 1822.

  The position, shape, size, and number of the second recesses 1822 correspond to the position, shape, size, and number of the protrusions 184. In the present embodiment, the number of second recesses 1822 is three. Although details will be described later, the shape and size of the second recess 1822 is determined so that the adhesive 10 ′ for adhering the light flux controlling member 180 to the base 160 during the manufacture of the light-emitting device 140 is appropriate in the second recess 1822. As long as it can flow, the material is not particularly limited.

  2B, w indicates the width of the second recess 1822, and in FIG. 2D, d indicates the depth of the second recess 1822. The width w and depth d of the second recess 1822 may or may not be constant in the radial direction of the light flux controlling member 180. From the viewpoint of facilitating the flow of the adhesive 10 ′ in the second recess 1822, the width w of the second recess 1822 is preferably, for example, the outer diameter of the projection 184 + 2 × 0.02 mm or more. That is, it is preferable that a groove having a width of 0.02 mm or more is formed around the convex portion 184, and this groove is preferably opened on the side surface of the light flux controlling member 180. Moreover, it is preferable that the depth d of the 2nd recessed part 1822 is 0.02-0.3 mm, for example. From the above viewpoint, it is preferable that the cross-sectional area of the second concave portion 1822 in the cross section perpendicular to the radial direction of the light flux controlling member 180 increases from the inside to the outside of the light flux controlling member 180. That is, it is preferable that the width w of the second recess 1822 becomes wider in the radial direction of the light flux controlling member 180 from the inner side to the outer side of the light flux controlling member 180. The depth of the second recess 1822 is preferably deeper from the inside toward the outside in the radial direction of the light flux controlling member 180.

  The material of the light flux controlling member 180 is not particularly limited as long as it can transmit light having a desired wavelength and has a desired heat resistance. Examples of the material of the light flux controlling member 180 include a silicone resin composition.

(Method for manufacturing light emitting device)
Hereinafter, a method for manufacturing the light emitting device 140 will be described. First, the substrate 130, the base 160, the light emitting element 170, and the light flux controlling member 180 are prepared. The substrate 130, the base body 160, and the light emitting element 170 may be off-the-shelf products. The base 160 and the light emitting element 170 may be packaged in advance. The light flux controlling member 180 can be manufactured by, for example, an injection molding method.

  Next, the light emitting device 140 is assembled. When the base body 160 and the light emitting element 170 are not packaged, the base body 160 and the light emitting element 170 are packaged by disposing and fixing the light emitting element 170 in the light emitting element recess 161 of the base body 160. At this time, a method for fixing the light emitting element 170 to the base 160 is not particularly limited. For example, the light emitting element recess 161 may be filled with a resin transparent to light emitted from the light emitting element 170 in a state where the light emitting element 170 is disposed in the light emitting element recess 161 of the base 160.

  Next, the base body 160 is placed on the substrate 130 and fixed. At this time, a method for fixing the base 160 on the substrate 130 is not particularly limited. For example, the substrate 160 can be fixed on the substrate 130 by heat welding, an adhesive, or the like.

  Next, the light flux controlling member 180 is fixed on the base 160. 3A and 3B are schematic views showing a process of fixing the light flux controlling member 180 to the base 160. FIG. First, an appropriate amount of the adhesive 10 ′ is injected into the first recess 162 of the base body 160 (see FIG. 3A). In a state where the adhesive 10 ′ is disposed in the first recess 162 of the base body 160, the light emitting surface of the light emitting element 170 and the incident surface 181 of the light flux controlling member 180 face each other, and the back surface of the light flux controlling member 180. The light flux controlling member 180 is arranged so that 182 and the top surface of the base 160 are in contact with each other. Finally, the adhesive 10 ′ is cured to fix the light flux controlling member 180 to the base body 160 (see FIG. 3B). In the light emitting device 140, the adhesive 10 is filled in at least the gap. Excess adhesive 10 that is not accommodated in the gap is filled in the second recess 1822. In the present embodiment, the adhesive 10 is filled in the gap and the second recess 1822.

  Through the above procedure, the light-emitting device 140 according to the present embodiment can be manufactured. In the step of fixing the light flux controlling member 180 to the base 160, the adhesive 10 ′ disposed in the first recess 162 of the base 160 is accommodated in a gap between the inner surface of the first recess 162 and the side of the protrusion 184. The excess adhesive 10 ′ that is not entered enters the second concave portion 1822 formed on the back surface 182 of the light flux controlling member 180 so as to communicate with the gap, and further, the inside of the second concave portion 1822 extends outside the light flux controlling member 180. Can move toward. For this reason, in the present embodiment, it is suppressed that excess adhesive 10 ′ flows between the back surface 182 of the light flux controlling member 180 and the top surface of the base 160 and reaches the incident surface 181 of the light flux controlling member 180. it can. In addition, since the gap communicates with the outside through the second recess 1822, air can be prevented from being sealed between the projection 184 and the inner surface of the second recess 1822. Therefore, it is possible to prevent the light flux controlling member 180 from being fixed in a state of being separated from the base 160 by the adhesive 10 or air. As described above, in the light emitting device 140, the light flux controlling member 180 can be appropriately fixed to the base body 160.

  In addition, light flux controlling member 180 of light emitting device 140 according to the present embodiment has flange 185. For this reason, even if the excess adhesive 10 ′ flows out to the outside of the flange 185, it is possible to suppress the adhesive 10 ′ from reaching and attaching to the emission surface 183.

(effect)
In light emitting device 140 according to the present embodiment, convex portion 184 is fitted into first concave portion 162 such that a gap is formed between first concave portion 162 and convex portion 184 of base 160. The rear surface 182 of the light flux controlling member 180 surrounds the base end portion of the convex portion 184 so as to communicate with the gap, and opens to the outer side in the radial direction of the light flux controlling member 180 and the back side of the light flux controlling member 180. A second recess 1822 is formed. For this reason, at the time of manufacturing the light emitting device 140, the excess adhesive 10 ′ that is not accommodated in the gap can move inside the second recess 1822 toward the outside of the light flux controlling member 180. Therefore, the surplus adhesive 10 ′ flows between the back surface 182 of the light flux controlling member 180 and the top surface of the base 160 and reaches the optical surface of the light flux controlling member 180 (incident surface 181 in the present embodiment). Can be suppressed. As a result, it is possible to suppress a decrease in optical characteristics of the light flux controlling member 180 due to adhesion of the adhesive 10 that has moved from the vicinity of the convex portion 184 of the light flux controlling member 180 to the optical surface.

  The shape of the light flux controlling member of the light emitting device according to the present invention is not limited to the shape of the light flux controlling member 180 according to the above embodiment. 4A to 4C are diagrams showing configurations of light flux controlling members 180a to 180c according to the first to third modifications. 4A is a bottom view of a light flux controlling member 180a according to Modification 1, FIG. 4C is a cross-sectional view of a light flux controlling member 180b according to Modification 2, and FIG. 4C is a light flux controlling member according to Modification 3. It is sectional drawing of 180c.

  As shown in FIG. 4A, the shape of the convex portion 184a of the light flux controlling member 180a is the same as the shape in which a part of the cylinder is cut out along the fitting direction of the convex portion 184a, so-called D-cut cylindrical shape. It may be. The side surface (curved surface) of the convex portion 184a facing the inner side of the light flux controlling member 180a is in contact with the inner side surface of the second concave portion 1822, and the side surface (planar surface) of the convex portion 184a facing the outer side of the light flux controlling member 180a. ) Is separated from the inner surface of the second recess 1822, and the light flux controlling member 180 a is disposed on the base body 160. That is, in the first modification, the gap is formed only on the outer edge side of the light flux controlling member 180a in the first recess 162. Thereby, at the time of manufacturing the light emitting device 140, the excessive adhesive 10 ′ easily moves toward the outer edge side of the light flux controlling member 180 a and hardly moves toward the inner side. Thus, the fact that the gap is disposed only on the outer edge side of the light flux controlling member 180a means that the light flux resulting from the adhesion of the adhesive 10 that has moved from the periphery of the convex portion 184a of the light flux controlling member 180a to the optical surface. This is more preferable from the viewpoint of suppressing the deterioration of the optical characteristics of the control member 180a.

  As shown in FIG. 4B, the shape of the connecting portion between the convex portion 184b and the second concave portion 1822 of the light flux controlling member 180b may be an R shape. That is, the convex portion 184b and the second concave portion 1822 may be connected to each other with a smooth curved surface. It is preferable that the shape of the connecting portion is an R shape from the viewpoint of suppressing cracks in the light flux controlling member 180b that may occur at the proximal end portion of the convex portion 184b.

  As shown in FIG. 4C, the optical surface on the front side of the light flux controlling member 180c may be a reflecting surface 186c. Further, the concave portion for the incident surface may not be formed on the back surface 182c of the light flux controlling member 180c. In this case, the light flux controlling member 180c further includes an emission surface 187c arranged so as to surround the reflection surface 186c. The shape of the incident surface (first optical surface) 181c is a plane. The reflecting surface 186c reflects the light incident on the inside of the light flux controlling member 180c at the incident surface 181c. The emission surface 187c emits the light reflected by the reflection surface 186c to the outside of the light flux controlling member 180c.

  The light emitting device according to the present invention can be applied to, for example, a backlight of a liquid crystal display device or general illumination.

10 ′, 10 Adhesive 100 Display device 110 Surface light source device 120 Irradiated member 130 Substrate 140 Light emitting device 150 Light diffusing member 160 Base 161 Light emitting element concave portion 162 First concave portion 170 Light emitting element 180, 180a-c Light flux controlling member 181, 181c incident surface 182, 182c back surface 1821 incident surface recess 1822 second recess 183, 187c exit surface 183a first exit surface 183b second exit surface 183c third exit surface 184, 184a, 184b projecting portion 185 flange 186c reflecting surface CA light beam Central axis of control member OA Optical axis of light emitting element

Claims (7)

A base body having a first recess formed on one surface;
A light emitting device held on the substrate;
A light flux controlling member disposed on the base and the light emitting element, for controlling the light distribution of the light emitted from the light emitting element;
Have
The light flux controlling member is
A first optical surface that is disposed on the back side thereof and allows light emitted from the light emitting element to enter the light flux controlling member;
It is arranged on the front side, abuts against the second optical surface for transmitting or reflecting the light incident on the first optical surface and the one surface of the substrate, and on the outside of the first optical surface A back surface extending along a direction orthogonal to the central axis of the light flux controlling member;
A convex portion that is arranged on the back side and is fitted in the first concave portion such that a gap is formed between the inner surface of the first concave portion, and
Have
A second recess is formed on the back surface so as to surround the base end portion of the convex portion so as to communicate with the gap and open to the outer side in the radial direction of the light flux controlling member and the back side of the light flux controlling member. Has been
The light flux controlling member is fixed to the base body through a cured product of an adhesive filled in at least the gap,
Light emitting device. The gap is
In the first recess, it is disposed only on the outer edge side of the light flux controlling member, and extends along the fitting direction of the protrusion.
The light emitting device according to claim 1.   The light emitting device according to claim 1, wherein a shape of the convex portion is the same as a shape in which a part of a cylinder is cut out along a fitting direction of the convex portion.   The light emitting device according to any one of claims 1 to 3, wherein the second optical surface is an emission surface for emitting light incident on the first optical surface to the outside of the light flux controlling member. The light flux controlling member further includes a third optical surface disposed so as to surround the second optical surface,
The second optical surface is a reflecting surface for reflecting light incident on the light flux controlling member at the first optical surface,
The third optical surface is an emission surface for emitting the light reflected by the second optical surface to the outside of the light flux controlling member.
The light-emitting device as described in any one of Claims 1-3. The light emitting device according to any one of claims 1 to 5,
A light diffusing member that diffuses while transmitting light emitted from the light emitting device;
A surface light source device. A surface light source device according to claim 6;
A member to be irradiated with light emitted from the surface light source device;
A display device.

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