JP5749555B2 - Luminous flux control member, light emitting device including the luminous flux control member, and surface light source device including the light emitting device - Google Patents

Description

  The present invention relates to a light flux controlling member, a light emitting device including the light flux controlling member, and a surface light source device including the light emitting device, and particularly suitable for controlling a traveling direction of light emitted from a light emitting element. The present invention relates to a control member, a light emitting device including the light flux controlling member, and a surface light source device including the light emitting device.

  Conventionally, edge light type or direct type surface light source devices have been used for applications such as backlights for liquid crystal display devices and internally illuminated signboards.

  Here, the edge light type surface light source device is known as a method for extracting light from a light source disposed on a side end surface of a light guide plate to a surface side (viewing side) orthogonal to the side end surface by the light guide plate. On the other hand, the direct type is known as a system in which a plurality of point light sources are arranged on the back side (directly below) of the light diffusion plate, and the light from each light source is diffused by the light diffusion plate and taken out to the front side (Patent Literature). 1).

  Among these methods, the direct type method is advantageous in terms of high brightness, and this method is often employed particularly in applications where large area image display and light emission are performed.

  In recent years, in such a direct type, a surface light source device has been developed that enables illumination of a large area with a small number of point light sources (see Patent Document 2).

  Side-view LEDs are used in the surface light source device shown in FIGS. 5 and 6 of Patent Document 2, and light emitted from the LEDs emitted mainly in parallel with the LED mounting surface is inclined (curved). By being reflected by the formed light reflecting surface member, the entire surface of the light emitting surface member is uniformly irradiated.

  When a top view LED that emits light in a direction orthogonal to the LED mounting surface is used instead of the side view LED, a light flux controlling member for changing the traveling direction of the light to a direction parallel to the LED mounting surface is used. This is effective for obtaining a high-quality surface light source device having a light emitting surface.

  FIG. 18 is a plan view showing a conventional example of this type of direct-type surface light source device. 19 is a cross-sectional view taken along the line AA in FIG. 18, and FIG. 20 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIGS. 18 to 20, the surface light source device 1 has a rectangular housing 2 in plan view, and the inner surface of the housing 2 is in the Y-axis direction (vertical direction in FIG. 18). A bottom surface 3 that is long in the X-axis direction (lateral direction in FIG. 18) located in the center, side surfaces 4 and 5 that are vertically connected to both ends of the bottom surface 3 in the X-axis direction, and the Y-axis of the bottom surface 3 It is comprised by the reflective surfaces 6 and 7 connected to the both ends in the direction.

  As shown in FIG. 19, on the bottom surface 3, a plurality (nine) of light emitting elements 12 made up of light emitting diodes (LEDs) or the like are arranged in a line at equal intervals in the X-axis direction as point light sources. In addition, each light emitting element 12 is arrange | positioned on the bottom face 3 in the state mounted on the board | substrate 13 provided with the lead and control circuit (not shown) etc. which apply the electrical signal with respect to these. Each light emitting element 12 emits light according to a predetermined light distribution with a certain degree of directivity (Lambertian distribution in the case of LED) toward the front (upward in FIGS. 19 and 20). It has become. At this time, the light emitting element 12 is arranged at the center in the Y axis direction of the housing 2 so that the central axis (center light) of the emitted light of each light emitting element 12 is in a state parallel to the Z axis direction.

  As shown in FIG. 20, the reflecting surfaces 6 and 7 are formed as upward inclined surfaces that are inclined in the Z-axis direction (vertical direction in FIG. 20) as they are separated from the light emitting element 12. Furthermore, as shown in FIG. 20, the reflecting surfaces 6 and 7 are formed in a plane-symmetric shape with a virtual plane S perpendicular to the bottom surface 3 that bisects the bottom surface 3 in the Y-axis direction as a symmetry plane. That is, the inclination angles of the reflecting surfaces 6 and 7 with respect to the bottom surface 3 are the same. And both these reflective surfaces 6 and 7 are formed of the reflective member. As the reflecting member, for example, UXSP188 (manufactured by Teijin DuPont) or the like is used.

  Further, as shown in FIGS. 18 to 20, a plurality of light flux control members 14 for controlling the traveling direction of the emitted light of each light emitting element 12 are arranged on each light emitting element 12. These light flux controlling members 14 are made of, for example, a resin material such as PMMA (polymethyl methacrylate), PC (polycarbonate) and EP (epoxy resin), or a translucent material such as glass.

  Here, FIG. 21 is a plan view showing the light flux controlling member 14. FIG. 22 is a bottom view of FIG. 23 is a cross-sectional view taken along the line AA in FIG. 21, and FIG. 24 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIGS. 22 to 24, the light flux controlling member 14 has a light emitting element facing surface portion 15 disposed to face the light emitting element 12 in the Z-axis direction (light emission direction). Further, as shown in the respective drawings, the light flux controlling member 14 has an anti-light emitting element facing surface portion 16 formed on the opposite side of the light emitting element 12 in the Z-axis direction with respect to the light emitting element facing surface portion 15. Furthermore, as shown in each drawing, the light flux controlling member 14 has an outer peripheral surface 17 extending from the outer peripheral end of the light emitting element facing surface portion 15 toward the side opposite to the light emitting element 12. Furthermore, as shown in the drawings, the light flux controlling member 14 is on the opposite side of the outer peripheral surface 17 from the light emitting element 12 in the Z-axis direction and on the outer side in the Y-axis direction with respect to the counter-light emitting element facing surface portion 16. It has the output surface 18 formed in this.

Specifically, as shown in FIGS. 23 and 24, the light emitting element facing surface portion 15 is formed as a substantially truncated cone-shaped concave portion 15 for allowing light emitted from the light emitting element 12 (not shown) to enter. Yes. Here, as shown in FIGS. 22-24, the recessed part 15 has the 1st entrance plane 19 which exhibits the concentric circle with the optical axis OA in the bottom view formed as a plane orthogonal to the optical axis OA. As shown in FIG. 23, the first incident surface 19 has a first light (light beam) emitted from the light emitting element 12 (not shown) on the smaller angle side with respect to the optical axis OA (light beam). light beam) _{L 1} is incident. However, in FIG. 23, the first light L _1, is representatively shown as a single beam contained therein. Then, the first light L ₁ incident on the first incident surface 19 is refracted so that the angle with respect to the optical axis OA is generally reduced on the first incident surface 19 in accordance with Snell's law (the central light for normal incidence is Then, the light travels on the optical path inside the light flux controlling member 14 toward the counter light emitting element facing surface portion 16. Further, as shown in FIGS. 22 to 24, the recess 15 has a second incident surface 20 extending from the outer peripheral end of the first incident surface 19 toward the light emitting element 12 side. The two incident surfaces 20 are formed on a tapered surface concentric with the optical axis OA so that the inner diameter gradually increases toward the light emitting element 12 side. As shown in FIG. 23, the second incident surface 20 has second light (light flux) outside the _first light L ₁ out of light (light flux) emitted from the light emitting element 12 (not shown). ) _{L 2} is incident. However, in FIG. 23, the second light L _2, are representatively shown as one light beam contained therein. The second light L ₂ incident on the second incident surface 20 is refracted on the second incident surface 20 and travels on the optical path inside the light flux controlling member 14 toward the outer peripheral surface 17.

Further, as shown in FIG. 23, the outer peripheral surface 17 has a concentric curve with the optical axis OA so that the outer diameter gradually increases toward the side opposite to the light emitting element 12 and slightly bulges outward in the radial direction. The outer peripheral surface 17 is formed as a first total reflection surface 17. That is, as shown in FIG. 23, the first total reflection surface 17, the second light L ₂ which advances within the optical path of the light flux controlling member 14 after entering the second incident surface 20, than the critical angle Is incident at a large incident angle. Then, the second light L ₂ incident inside is totally reflected by the first total reflection surface 17 in a direction in which the angle with respect to the optical axis OA is reduced as a whole, and then on the optical path inside the light flux controlling member 14. It proceeds toward the counter light emitting element facing surface portion 16.

Furthermore, as shown in FIG. 23, the anti-light emitting element facing surface portion 16 is formed in a plane-symmetric shape with the above-described virtual plane S (a predetermined plane including the optical axis OA) as a plane of symmetry and is parallel to the virtual plane S. When viewed from a direction orthogonal to the optical axis OA (when viewed from the side), the shape expands in a direction orthogonal to the virtual plane S toward the opposite side of the light emitting element 12. Yes. More specifically, the anti-light-emitting element facing surface portion 16 has a circular shape in the plan view and an intersection position with the virtual plane S is a valley in an arbitrary cross section (for example, FIG. 23) orthogonal to the virtual plane S. It is formed on a surface that exhibits a V-shape. Such an anti-optical element facing surface portion 16 is a second total reflection surface 16. That is, as shown in FIG. 23, the second total reflection surface 16 travels on the optical path inside the light flux controlling member 14 after entering the first incident surface 19 (arrived from the first incident surface 19 side). first light L ₁ is internally incident at a large incident angle than the critical angle. At this time, the second total reflection surface 16 has the second light L ₂ that has traveled on the optical path inside the light flux controlling member 14 after being totally reflected by the first total reflection surface 17, more than the critical angle. Internal incidence with a large incident angle. The second total reflection surface 16 has both the first incident light L ₁ and the second light L ₂ incident on the inside thereof in plane symmetry with each other with the virtual plane S as a symmetry plane (opposite sides) (see FIG. 23 in the horizontal direction), and the optical path is changed so as to be substantially orthogonal to the optical axis OA. More specifically, the light L ₁ and L _{2 that} are internally incident on the left half of FIG. 23 of the second total reflection surface 16 are totally reflected toward the left side, Lights L ₁ and L ₂ (not shown) internally incident on the right half in FIG. 23 are totally reflected toward the right side.

Furthermore, as shown in FIGS. 21 to 23, the exit surface 18 is formed in a cylindrical surface concentric with the optical axis OA, and the exit surface 18 is directed to both sides by the second total reflection surface 16. first light L ₁ and the second light L _2, which is totally reflected Te is internally incident respectively. The exit surface 18 to emit first light L ₁ and the second light L ₂ which is internally incident on the left and right both sides of the light flux controlling member 14. FIG. 25 shows the traveling directions of the first light L ₁ and the second light L ₂ emitted at this time, and three different light beams together with a plan view of the light flux controlling member 14.

Then, the first light L ₁ and the second light L ₂ emitted from the emission surface 18 in this manner are reflected by the inclined reflection surface 10 and are emitted from the surface light source device 1 as shown in FIG. Proceed toward (upward in FIG. 20).

  Further, as shown in FIG. 23, the light flux controlling member 14 has a cylindrical holder 22 concentric with the optical axis OA extended from the lower end portion of the emission surface 18 toward the light emitting element 12 side. The holder 22 surrounds the first total reflection surface 17 from the outside in the radial direction.

Returning to FIGS. 18 to 20, the surface light source device 1 has an optical sheet 25 that shields the front opening of the housing 2, and this optical sheet 25 is arranged on the optical axis OA of each light flux controlling member 14. The light flux controlling members 14 and the inclined reflecting surface 10 are disposed so as to be orthogonal to each other. The first light L ₁ and the second light L ₂ reflected by the inclined reflecting surface 10 are incident on the optical sheet 25 from the rear (downward in FIG. 20). Then, the optical sheet 25 emits the incident light as light having a rectangular spread when viewed in plan. As the optical sheet 25, DBEF (manufactured by 3M), a diffusion sheet, a diffusion plate, a prism sheet, or the like is used.

Special table 2009-542017 JP 2010-9785 A

However, conventionally, since the shape of the emission surface 8 on the plan view is a cylindrical surface having a positive power, the emitted lights L ₁ and L ₂ from the emission surface 8 are X as shown in FIG. It was focused light in the axial direction.

  For this reason, when the irradiation area of the emitted light of each light flux controlling member 14 on the inclined reflecting surface 10 becomes narrow in the X-axis direction, the irradiated portion (bright part) of the emitted light of each light flux controlling member 14 on the inclined reflecting surface 10 ) Since the light reaching between them is insufficient, there is a problem that the luminance on the light emitting surface becomes non-uniform when used as a surface light source.

  Therefore, the present invention has been made in view of such problems, and a light flux controlling member that can improve the uniformity of luminance when used as a surface light source by increasing the light flux diameter of the emitted light, It is an object of the present invention to provide a light emitting device including the light flux controlling member and a surface light source device including the light emitting device.

In order to achieve the above-mentioned object, a light flux controlling member according to claim 1 of the present invention is a light flux controlling member that controls the traveling direction of light emitted from a light emitting element, and is opposed to the light emitting element. A light emitting element facing surface portion to be disposed; an anti-light emitting element facing surface portion formed on the opposite side of the light emitting element with respect to the light emitting element facing surface portion; and an outer peripheral end of the light emitting element facing surface portion opposite to the light emitting element An outer peripheral surface extending toward the outer peripheral surface, and an emission surface formed on the opposite side of the outer peripheral surface to the light emitting element and outside the counter light emitting element opposing surface portion, , A recess for allowing the light emitted from the light emitting element to enter, the recess being formed in a plane perpendicular to the optical axis, and a first one on the center side of the light emitted from the light emitting element. A first incident surface on which light is incident and the first incident surface; A second incident surface that extends from the outer peripheral end of the incident surface toward the light emitting element side and on which the second light outside the first light of the light emitted from the light emitting element is incident. And the outer peripheral surface is formed such that an outer diameter gradually increases toward the opposite side of the light emitting element, and the second light incident on the second incident surface is directed toward the counter light emitting element facing surface portion. The anti-light-emitting element facing surface portion is formed in a plane-symmetric shape with a predetermined plane including the optical axis as a symmetry plane and is orthogonal to the predetermined plane. In an arbitrary cross section, the cross-section position with the predetermined plane has a V shape having a valley, and has a second total reflection surface that totally reflects the first light and the second light, and the emission surface Are formed in plane symmetry with the predetermined plane as a plane of symmetry. A first emission surface and a second emission surface for emitting the first and second lights totally reflected by the total reflection surface, wherein the first emission surface and the second emission surface are the second total reflection; The first and second lights totally reflected by the surface are refracted so as to spread in the longitudinal direction of the valley and are emitted in a diverged state.

According to the first aspect of the present invention, the first and second light beams totally reflected on the second total reflection surface are spread in the longitudinal direction of the valley by the first emission surface and the second emission surface. Since the light can be refracted and emitted, the irradiation range can be increased, and as a result, the luminance uniformity when used as a surface light source can be improved.

A feature of the light flux controlling member according to claim 2 is a light flux controlling member that controls a traveling direction of light emitted from the light emitting element, the light emitting element facing surface portion disposed to face the light emitting element, The light emitting element facing surface portion includes a counter light emitting element facing surface portion formed on the opposite side of the light emitting element, and an emission surface formed outside the counter light emitting element facing surface portion. An incident region for allowing light emitted from the light emitting element to enter, and the incident region has a concentric annular shape centered on the optical axis when viewed from the optical axis direction, and a cross section including the optical axis; A plurality of protrusions that are adjacent to each other in the radial direction so as to have a saw blade shape, and the protrusions receive light emitted from the light emitting element, and incident surfaces that refract the incident light; and The optical axis with respect to the incident surface A first total reflection surface that is formed at a reference radial outer position and totally reflects light incident from the incident surface toward the anti-light emitting element facing surface portion; and the anti-light emitting element facing surface portion is It is formed in a plane-symmetric shape with a predetermined plane including the optical axis as a plane of symmetry, and in an arbitrary cross section orthogonal to the predetermined plane, it exhibits a V shape in which the intersection point with the predetermined plane is a valley. A second total reflection surface that further totally reflects the light totally reflected by the first total reflection surface, and the emission surface is formed in plane symmetry with the predetermined plane as a symmetry plane, The first and second emission surfaces for emitting light totally reflected by the second total reflection surface, and the first and second emission surfaces are totally reflected by the second total reflection surface. refracted been light so as to spread in the longitudinal direction of the trough In that it is formed in a shape to be emitted in a state of being diverged.

According to the second aspect of the invention, the light totally reflected by the second total reflection surface is refracted and emitted so as to spread in the longitudinal direction of the valley by the first emission surface and the second emission surface. Therefore, the irradiation range can be increased, and as a result, the luminance uniformity when used as a surface light source can be improved.

  Further, the light beam control member according to claim 3 is characterized in that, in claim 1 or 2, the first emission surface and the second emission surface are formed in parallel to the predetermined plane. It is in.

  According to the third aspect of the invention, the first emission surface and the second emission surface can appropriately emit divergent light with a simple surface shape.

  Still further, the light flux controlling member according to claim 4 is characterized in that, in claim 1 or 2, the first emission surface and the second emission surface are on the predetermined plane side when viewed from the optical axis direction. It is in the point formed in the concave curved surface which exhibits the shape curved so that it may dent into.

  According to the fourth aspect of the invention, the first emission surface and the second emission surface can appropriately emit divergent light with a simple surface shape.

  The light emitting device according to claim 5 is characterized in that the light flux controlling member and the light emitting element according to any one of claims 1 to 4 are provided.

  According to the fifth aspect of the present invention, the uniformity of luminance when used as a surface light source can be improved by increasing the irradiation range of the emitted light from the light flux controlling member.

  Furthermore, the surface light source device according to claim 6 is characterized in that the light emitting device according to claim 5 has a predetermined interval in an alignment direction parallel to the predetermined plane and orthogonal to the optical axis according to claims 1-4. A plurality of light emitting devices are arranged and arranged, and the first light emitting surface and the second light emitting device are disposed at positions on the light emitting side of the light beam control members from the first light emitting surface and the second light emitting surface with respect to the light emitting devices. This is in that a reflection / diffusion means for reflecting and / or diffusing light emitted from the surface is provided.

  According to the sixth aspect of the present invention, it is possible to realize a good surface light source with reduced luminance unevenness by arranging and arranging the light beam control members having a large irradiation range of the emitted light.

  According to the light flux controlling member according to the present invention, it is possible to increase the area to be irradiated by the light emitted from the light emitting device. By using this light emitting device for the surface light source device, the luminance on the light emitting surface of the surface light source device is uniform. Can be improved.

The top view which shows embodiment of the light beam control member which concerns on this invention Bottom view of FIG. AA sectional view of FIG. BB cross section of FIG. In embodiment of the light beam control member which concerns on this invention, the schematic diagram which shows the emitted light from an output surface as three typical light rays The top view which shows embodiment of the surface light source device which concerns on this invention AA sectional view of FIG. BB sectional view of FIG. The top view which shows the 1st modification of a light beam control member Bottom view of FIG. AA sectional view of FIG. BB sectional view of FIG. Bottom view showing a second modification of the light flux controlling member AA sectional view of FIG. BB sectional view of FIG. Configuration diagram showing an embodiment of the present invention In an embodiment of the present invention, a graph showing the measurement result of luminance A plan view showing an example of a conventional surface light source device AA sectional view of FIG. BB sectional view of FIG. A plan view showing an example of a conventional light flux controlling member 21 is a bottom view of FIG. AA sectional view of FIG. BB sectional view of FIG. In the conventional light flux controlling member, the schematic diagram showing the outgoing light from the outgoing surface as three representative light beams

  Embodiments of a light flux controlling member, a light emitting device, and a surface light source device according to the present invention will be described below with reference to FIGS.

  Note that portions having the same or similar basic configuration as those in the related art will be described using the same reference numerals.

  FIG. 1 is a plan view showing a light flux controlling member 30 in the present embodiment. FIG. 2 is a bottom view of FIG. 3 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 4 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIGS. 1 to 4, the light flux controlling member 30 in the present embodiment is a concave portion formed of a first incident surface 19 and a second incident surface 20 as light emitting element facing surface portions, similarly to the conventional light flux controlling member 14. 15, a first total reflection surface 17 as an outer peripheral surface, and a second total reflection surface 16 having a rectangular shape in a plan view as an anti-light emitting element facing surface portion. Since the optical functions of these components are the same as those in the prior art, the details are omitted.

  On the other hand, the configuration of the light exit surface of the light flux controlling member 30 in the present embodiment is different from the conventional one.

  That is, as shown in FIG. 1, the emission surface in the present embodiment is configured by a first emission surface 31 and a second emission surface 32 that are formed in a plane-symmetric shape with the above-described virtual plane S as a symmetry surface. Yes. The first emission surface 31 and the second emission surface 32 are formed in a plane parallel to the virtual plane S.

As shown in FIG. 3, the first exit surface 31 and the second exit surface 32 are totally reflected on the second total reflection surface 16 toward both sides symmetrical with respect to the virtual plane S. The first light L ₁ and the second light L ₂ are incident. However, in FIG. 3, the first light L ₁ and the second light L ₂ incident on each of the emission surfaces 31 and 32 are representatively illustrated as one light beam. Then, the first light L ₁ and the second light L ₂ incident on the emission surfaces 31 and 32 are emitted in a state of being diverged from the emission surfaces 31 and 32. FIG. 5 shows the light emitted from the light exit surfaces 31 and 32 as three representative light beams together with a plan view of the light flux controlling member 30.

  Such a light flux controlling member 30 in the present embodiment constitutes a light emitting device in the present embodiment by being opposed to the light emitting element 12 similar to the conventional one, and is disposed in the casing 2 similar to the conventional one. By doing so, the surface light source device in the present embodiment is configured.

  Here, FIG. 6 is a plan view showing the surface light source device 34 in the present embodiment. 7 is a cross-sectional view taken along the line AA in FIG. 6, and FIG. 8 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIG. 6, in this embodiment, when the virtual plane S is defined as an XZ plane passing through the origin of the Y coordinate, the conventional focused light (see FIG. 18) in the + Y direction and the −Y direction is used. In comparison, light flux controlling members 30 capable of emitting divergent light having a large irradiation range are arranged at equal intervals in the X-axis direction. The emitted light from each light flux controlling member 30 is irradiated onto the inclined reflecting surface 10 in a state where the irradiation area is expanded in the X-axis direction. As a result, the interval in the X-axis direction between the irradiated portions (bright portions) by the adjacent light flux controlling members 30 on the inclined reflecting surface 10 can be reduced, so that the light emitting surface of the surface light source device 34 is compared with the conventional case. The dark part between the bright parts can be reduced (the width in the X-axis direction is reduced) or removed.

  Moreover, since the output surfaces 31 and 32 which exhibit such an effect can be easily formed as a simple plane, cost can be suppressed.

  The present invention can be applied to various modifications as shown below.

(First modification)
That is, FIG. 9 is a plan view showing a first modification of the light flux controlling member 30. FIG. 10 is a bottom view of FIG. 11 is a cross-sectional view taken along the line AA in FIG. 9, and FIG. 12 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIG. 9, in the present modification, the first emission surface 31 and the second emission surface 32 have a plane-symmetric shape with the imaginary plane S as the symmetry plane, and are viewed from the direction of the optical axis OA. It is formed on a concave surface curved in an arc shape on the virtual plane S side. The position where the dimension between the two exit surfaces 31 and 32 is the minimum is coincident with the cross section (FIG. 11) perpendicular to the virtual plane S and including the optical axis OA. However, the curved shape of the concave surface need not be limited to an arc (spherical surface), and may be an aspherical surface.

As shown in FIG. 11, the first emission surface 31 and the second emission surface 32 in this modification also diverge light L ₁ and L ₂ totally reflected on both sides by the second total reflection surface 16. It can be emitted as light. At this time, since each of the emission surfaces 31 and 32 has negative power, it is possible to emit divergent light that can irradiate a wider area than in the case of a planar emission surface (see FIG. 1). Therefore, according to the present modification, it is possible to reduce or remove the dark part more effectively than when each of the emission surfaces 31 and 32 is a plane.

(Second modification)
Next, FIG. 13 is a bottom view showing a second modification of the light flux controlling member 30. 14 is a cross-sectional view taken along the line AA in FIG. 13, and FIG. 15 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIGS. 13 to 15, in the light flux controlling member 30 in the present modification, the light emitting element facing surface portion has a Fresnel surface-shaped incident region 35 instead of the recessed portion 15. That is, the incident region 35 has a concentric annular shape centered on the optical axis OA when viewed from the optical axis OA direction, and a plurality of adjacent regions in the radial direction such that a cross section including the optical axis OA has a sawtooth shape. A protrusion 36 is provided. As shown in FIG. 14 (partially enlarged view), each protrusion 36 receives light emitted from the light emitting element 12, and enters the incident surface 36a that refracts the incident light, and light with respect to the incident surface 36a. A first total reflection surface b that is formed at a radially outer position with respect to the axis OA and that totally reflects light incident from the incident surface a toward the second total reflection surface 16 (opposite surface of the light-emitting element). Have. However, the incident surface 36a is not necessarily limited to a flat surface, and may be formed on a bent surface such that the distal end side has a greater radial outward inclination with respect to the optical axis OA than the proximal end side. By doing so, it is possible to avoid manufacturing disadvantages (for example, insufficient filling of the resin material on the transfer surface of the tip when molding using a mold) due to the tip of the protrusion 36 being too sharp. Can do. In addition, although the center part 35a in the incident area | region 35 is formed in the flat surface orthogonal to the optical axis OA, this center part 35a injects the light from the light emitting element 12 toward the 2nd total reflection surface 16 side. It is supposed to let you. At this time, the light that enters the light flux controlling member 30 from the central portion 35a is refracted in a direction in which the angle with respect to the optical axis OA is reduced except for the central light passing on the optical axis OA.

  The light flux controlling member 30 in this modification has the second total light reflected by the Fresnel-shaped first total reflection surface 36b or transmitted through the central portion 35a by the light emitted from the light emitting element 12 incident on the incident region 35. It can be appropriately advanced toward the reflecting surface 16 side.

  Then, the light that has arrived from the incident region 35 side is totally reflected by the second total reflection surface 16 toward both sides that are symmetrical with respect to the virtual plane S, and the first emission surface 31 and the second emission surface. 32 can be emitted as diverging light.

  Thereby, the shortage of the light quantity between the irradiation parts (bright part) by the adjacent light beam control member 30 on the inclined reflective surface 10 can be compensated similarly to the structure of FIGS.

  In addition to this, the incident area 35 in the present modification may be combined with the concavely-curved first exit surface 31 and second exit surface 32 in the first modification.

  Next, as an embodiment of the present invention, the results of ray tracing simulation and luminance measurement for the configuration shown in FIGS. 1 to 8 will be described by comparison with a configuration using a conventional light flux controlling member 14.

  In the present embodiment, as described above, the alignment direction of the light emitting elements 12 (light flux control members 30 and 14) is the X-axis direction, the direction orthogonal to the virtual plane S and the optical axis OA is the Y-axis direction, and the optical axis OA direction. An XYZ orthogonal coordinate system in which the (thickness direction of the surface light source devices 34, 1) was defined as the Z-axis direction was defined. More specifically, as shown in FIGS. 16 and 18, the center of the light emitting surface of one light emitting element 12 arranged at the center of the nine light emitting elements 12 arranged along the X-axis direction. The point is (X, Y, Z) = (0, 0, 1) (unit is mm, the same applies hereinafter), and the origin (0, 0, 0) is opposed to the center point of the light emitting surface in the Z-axis direction. It was set as the position on the surface of the substrate 13 to be used.

  First, in this example, one representative light beam of the light beams emitted from one light emitting element 12 at the center was traced, and the XYZ coordinates at each measurement point of this representative light beam were measured. The specific dimensions of the surface light source device are as shown in FIG. And the measurement result in each measurement point became what is shown in the following Table 1 and Table 2. Table 1 shows the measurement results for the configuration of the present invention, and Table 2 shows the measurement results for the conventional configuration.

  As shown in Table 1 and Table 2, in the configuration of the present invention and the conventional configuration, the XYZ coordinates of the representative light beam from the light emitting element 12 are the emission point (light emitting element), the second incident surface (light flux controlling member), The measurement points on the first total reflection surface (light flux control member) and the second total reflection surface (light flux control member) coincide with each other. On the other hand, due to the difference in the shape of the exit surface, the XYZ coordinates of the representative rays of the configuration of the present invention and the conventional configuration are different from each other at each measurement point at the exit surface and Y = 100 mm.

  Here, paying attention to the X coordinate at the measurement point (Y = 100 mm), it can be seen that X = 4.79 mm in the conventional configuration, whereas X = −20.04 mm in the configuration of the present invention. It can be said that this result shows that the configuration of the present invention is more suitable for divergence of outgoing light from the outgoing surface than the conventional configuration.

  Next, in the luminance measurement for the configuration of the present invention and the conventional configuration, as shown in FIG. 16, the X value is variable, and the luminance on the light emitting surface of the surface light source device 1 is measured at a measurement position of Y = 100 mm (constant). Measurements were made. The measurement results are shown in FIG. The horizontal axis in FIG. 17 is the X coordinate at each measurement position (Y = 100 mm). Moreover, the vertical axis | shaft in the same figure is the brightness nonuniformity (dimensionalless amount) in a measurement point. The luminance unevenness at each measurement point can be obtained by the following equation.

Brightness unevenness = (Brightness of measurement point−A) / A (1)
However, A in the formula (1) is an average luminance (cd / mm ² ) of about 55 mm square around the measurement point.

  Here, in FIG. 17, the luminance unevenness according to the configuration of the present invention is indicated by a solid line, and the luminance unevenness according to the conventional configuration is indicated by a broken line. From this, it can be seen that the luminance unevenness is reduced over a wider range in the configuration of the present invention than in the conventional configuration.

  Therefore, according to this example, it can be said that the configuration of the present invention is superior in luminance uniformity as compared with the conventional configuration.

  In addition, this invention is not limited to embodiment mentioned above, A various change can be made in the limit which does not impair the characteristic of this invention.

  For example, the holder 22 may be provided as necessary. Further, as the reflection / diffusion means, a known diffusion surface that diffuses the emitted light from the light flux controlling member may be provided in place of or along with the inclined reflection surface 10.

12 Light emitting element 15 Recessed part (light emitting element facing surface part)
16 2nd total reflection surface 17 1st total reflection surface (outer peripheral surface)
19 First entrance surface 20 Second entrance surface 30 Light flux controlling member 31 First exit surface 32 Second exit surface

Claims (6)

A light flux controlling member for controlling the traveling direction of light emitted from the light emitting element,
A light emitting element facing surface portion disposed to face the light emitting element;
An anti-light emitting element facing surface portion formed on the side opposite to the light emitting element with respect to the light emitting element facing surface portion;
An outer peripheral surface extending from the outer peripheral end of the light emitting element facing surface portion toward the side opposite to the light emitting element;
An emission surface that is opposite to the light emitting element with respect to the outer peripheral surface and is formed outside the counter light emitting element facing surface portion;
The light emitting element facing surface portion is
Having a recess for allowing the light emitted from the light emitting element to enter;
The recess is
A first incident surface that is formed on a plane orthogonal to the optical axis and on which the first light on the center side of the light emitted from the light emitting element is incident;
A second incident that extends from the outer peripheral edge of the first incident surface toward the light emitting element side, and second light outside the first light out of the light emitted from the light emitting element is incident. Having a surface and
The outer peripheral surface is
The first total reflection is formed such that the outer diameter gradually increases toward the side opposite to the light emitting element, and totally reflects the second light incident on the second incident surface toward the counter light emitting element facing surface portion. Has a surface,
The anti-light emitting element facing surface portion is
A V-shape that is formed in a plane-symmetric shape with a predetermined plane including the optical axis as a plane of symmetry and that has an intersection point with the predetermined plane as a trough in an arbitrary cross section orthogonal to the predetermined plane. Presenting a second total reflection surface that totally reflects the first light and the second light;
The exit surface is
A first emission surface and a second emission surface that are formed in plane symmetry with the predetermined plane as a symmetry surface and emit the first and second light beams that are totally reflected by the second total reflection surface. Have
The first emission surface and the second emission surface are:
The first and second light beams totally reflected by the second total reflection surface are formed in a shape that refracts and spreads so as to spread in the longitudinal direction of the valley. Luminous flux control member. A light flux controlling member for controlling the traveling direction of light emitted from the light emitting element,
A light emitting element facing surface portion disposed to face the light emitting element;
An anti-light emitting element facing surface portion formed on the side opposite to the light emitting element with respect to the light emitting element facing surface portion;
An emission surface formed outside the counter-light-emitting element facing surface portion,
The light emitting element facing surface portion is
An incident region for entering the light emitted from the light emitting element;
The incident area is
When viewed from the optical axis direction, it has a plurality of protrusions adjacent to each other in the radial direction so as to exhibit a concentric ring centered on the optical axis and the cross section including the optical axis has a saw-tooth shape,
The protrusion is
An incident surface on which light emitted from the light emitting element is incident and refracts the incident light; and
A first total reflection surface that is formed at a radially outer position relative to the incident surface with respect to the optical axis and that totally reflects light incident from the incident surface toward the surface facing the anti-light-emitting element. And
The anti-light emitting element facing surface portion is
It is formed in a plane-symmetric shape with a predetermined plane including the optical axis as a plane of symmetry, and in an arbitrary cross section orthogonal to the predetermined plane, it exhibits a V shape in which the intersection point with the predetermined plane is a valley. And a second total reflection surface that further totally reflects the light totally reflected by the first total reflection surface,
The exit surface is
A first emission surface and a second emission surface that are formed in plane symmetry with the predetermined plane as a symmetry plane, and emit light totally reflected by the second total reflection surface;
The first emission surface and the second emission surface are:
The light flux controlling member, wherein the light beam control member is formed into a shape that emits the light totally reflected by the second total reflection surface in a state of being refracted and diverged so as to spread in the longitudinal direction of the valley . The first emission surface and the second emission surface are:
The light flux controlling member according to claim 1, wherein the light flux controlling member is formed in parallel to the predetermined plane. The first emission surface and the second emission surface are:
3. The light flux controlling member according to claim 1, wherein the light flux controlling member is formed into a concave curved surface having a curved shape so as to be recessed into the predetermined plane side when viewed from the optical axis direction. A light emitting device comprising the light flux controlling member according to claim 1 and a light emitting element. A plurality of light-emitting devices according to claim 5 are arranged in a line at a predetermined interval in an alignment direction parallel to the predetermined plane according to claims 1 to 4 and perpendicular to the optical axis,
The light emitted from the first emission surface and the second emission surface is reflected at positions on the light emission side from the first emission surface and the second emission surface of these light flux control members with respect to the plurality of light emitting devices. A surface light source device comprising a reflection / diffusion means for diffusing.

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