JP6274974B2 - Luminous flux control member, light emitting device, and illumination device - Google Patents

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, and an illumination device.

  In recent years, lighting devices (for example, LED bulbs and LED fluorescent tubes) that use light-emitting diodes (hereinafter also referred to as “LEDs”) as light sources have been used as lighting devices to replace light bulbs and fluorescent tubes from the viewpoint of energy saving and environmental conservation. It has come to be.

  As the LED fluorescent tube, a plurality of LEDs are arranged on a substrate at a predetermined interval, and a cover is arranged so as to cover these LEDs (for example, see Patent Document 1).

  Patent Document 1 describes an LED lighting device in which LEDs arranged on a substrate are covered with a cover. The LED lighting device described in Patent Document 1 includes a substrate, a plurality of LEDs arranged in a row on the substrate, a cylindrical lens having a ridge line along the arrangement direction of the LEDs, a plurality of LEDs, and a single cylindrical A light transmission cover arranged to cover the lens.

  In the LED lighting device described in Patent Document 1, light emitted from the LED is spread in a direction perpendicular to the LED arrangement direction by a cylindrical lens. And the light which permeate | transmitted the cylindrical lens permeate | transmits a light transmissive cover, and is radiate | emitted outside.

Special table 2011-513913 gazette

  However, in the LED lighting device described in Patent Document 1, the light distribution in the direction perpendicular to the LED arrangement direction is controlled, but the light distribution in the LED arrangement direction is not controlled. Therefore, when the light distribution is examined in the LED arrangement direction, it is too bright immediately above the LEDs and too dark between the LEDs. As described above, the LED lighting device described in Patent Document 1 has a problem of uneven brightness in the LED arrangement direction.

  Therefore, an object of the present invention is to distribute light in a direction perpendicular to the LED arrangement direction and the LED arrangement direction when applied to an illumination device (for example, an LED fluorescent tube) having a plurality of light emitting elements and a cover. An object of the present invention is to provide a light flux controlling member that can control the light distribution of light emitted from the light emitting elements so that the cover can be uniformly irradiated with light by a small number of light emitting elements.

  Another object of the present invention is to provide a light emitting device and a lighting device having the light flux controlling member.

  A light beam control member according to the present invention includes a first light beam control member and a second light beam control member, and controls the light distribution of light emitted from a light emitting element, wherein the first light beam control member Is formed at an incident surface on which a part of the light emitted from the light emitting element is incident and a position facing the light emitting element across the incident surface, and a part of the light incident on the incident surface is emitted from the light emitting element. Two total reflection surfaces that are reflected in two directions that are substantially perpendicular to the optical axis of the element and opposite to each other, and disposed between the two total reflection surfaces, and the light emitted from the light emitting element A slit that travels the other part in the direction along the optical axis as it is, and the incident surface, the total reflection surface, and a portion of the light incident from the incident surface, are arranged at positions facing each other across the slit, and 2 to guide the light reflected by the total reflection surface And a light exit surface that is formed on the outer surface of the light guide portion and emits the light guided by the light guide portion to the outside, and the second light flux controlling member covers the slit And a diffusive transmission part that diffuses and transmits the light that has traveled through the slit.

  Moreover, the light-emitting device which concerns on this invention has a light-emitting element and the light beam control member which concerns on this invention arrange | positioned so that the optical axis of the said light-emitting element may pass the said slit.

  Further, an illumination device according to the present invention includes a plurality of light emitting devices according to the present invention, a cover disposed via an air layer for each of the plurality of light emitting devices so as to cover the plurality of light emitting devices, Have

  ADVANTAGE OF THE INVENTION According to this invention, an illuminating device (for example, LED fluorescent tube) with small brightness nonuniformity can be provided.

1A to 1C are diagrams illustrating a configuration of a lighting device according to an embodiment. FIG. 2 is a cross-sectional view of the light flux controlling member according to the embodiment. 3A to 3C are diagrams showing the configuration of the first light flux controlling member. 4A to 4C are diagrams showing the configuration of the first light flux controlling member. 5A to 5E are diagrams for explaining the total reflection surface. 6A to 6C are diagrams illustrating the configuration of the second light flux controlling member. 7A to 7C are diagrams showing the configuration of the second light flux controlling member. FIG. 8A is a cross-sectional view showing a configuration of a light flux controlling member of a comparative example, FIG. 8B is a diagram for explaining simulation conditions, and FIG. 8C is a graph showing simulation results. FIG. 9A is a graph showing a simulation result, and FIG. 9B is a graph showing the relationship between the distance from the center of the slit and the luminance on the outer surface of the cover. FIG. 10A is a diagram showing a configuration of a light flux controlling member of a comparative example, FIG. 10B is a graph showing a simulation result, and FIG. 10C is a graph showing the distance from the center of the slit and the amount of light passing through the slit. It is a graph which shows a relationship. 11A and 11B are diagrams showing the configuration of a light flux controlling member according to a modification of the embodiment. 12A and 12B are diagrams showing a configuration of a light flux controlling member according to another modification of the embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, a lighting device that can be used in place of a fluorescent tube will be described as a representative example of the lighting device of the present invention.

(Configuration of lighting device)
FIG. 1 is a diagram showing a configuration of an illumination device 100 according to an embodiment of the present invention. 1A is a plan view of the lighting device 100, FIG. 1B is a cross-sectional view taken along line AA shown in FIG. 1A, and FIG. 1C is a partially enlarged cross-sectional view of a region surrounded by a broken line in FIG. 1B. It is.

  As illustrated in FIG. 1, the lighting device 100 includes a frame (housing) 110, a substrate 120, a plurality of light emitting devices 130 each having a light emitting element 132 and a light flux controlling member 150, and a cover 140. The plurality of light flux controlling members 150 are arranged in a line on the substrate 120 so as to be paired with one light emitting element 132, respectively.

  The plurality of light emitting elements 132 are light sources of the lighting device 100 and are arranged in a row on the substrate 120 attached to the frame 110. Each light emitting element 132 is disposed at a position facing an incident surface 153 of a light flux controlling member 150 described later. The light emitting element 132 is a light emitting diode (LED) such as a white light emitting diode. The frame 110 and the substrate 120 are made of a metal having high thermal conductivity such as aluminum or copper. When the substrate 120 does not require high thermal conductivity, a resin substrate in which a glass nonwoven fabric is impregnated with an epoxy resin may be used as the substrate 120.

  The cover 140 transmits the light emitted from the light flux controlling member 150 to the outside while diffusing it. The cover 140 is disposed via an air layer for each of the plurality of light emitting devices 130 so as to cover all the light emitting devices 130. The outer surface of the cover 140 is an effective light emitting area.

  The shape of the cover 140 is not particularly limited as long as it can cover all the light emitting devices 130 through the air layer. The shape of the cover 140 may be a cylindrical shape, or may be a shape in which a part of the cylinder is cut out. In the present embodiment, cover 140 has a shape in which a part of a cylinder is cut out. The material of the cover 140 is not particularly limited as long as it has light transparency. Examples of the material of the cover 140 include light transmissive resins such as polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), and styrene / methyl methacrylate copolymer resin (MS), and light transmissive glass. Etc. are included. Also, the means for imparting light diffusing power to the cover 140 is not particularly limited. For example, light diffusion treatment (for example, roughening treatment) may be performed on the inner surface or the outer surface of the cover 140, or scatterers such as beads may be dispersed in the light transmissive resin.

(Configuration of luminous flux control member)
FIG. 2 is a cross-sectional view of light flux controlling member 150 according to the present embodiment. As shown in FIG. 2, the light flux control member 150 includes a first light flux control member 151 and a second light flux control member 152. The light flux controlling member 150 controls the light distribution of the light emitted from the light emitting element 132. The first light flux control member 151 and the second light flux control member 152 are separately formed by integral molding. The material of the first light flux control member 151 and the second light flux control member 152 is not particularly limited as long as it can pass light having a desired wavelength. Examples of the material of the first light flux control member 151 and the second light flux control member 152 include light transmissive resins such as polymethyl methacrylate (PMMA), polycarbonate (PC), and epoxy resin (EP), and light transmissive resins. Glass etc. are included. Further, light scatterers such as beads may be dispersed inside the first light flux controlling member 151 and the second light flux controlling member 152.

  3 and 4 are diagrams showing the configuration of the first light flux controlling member 151. FIG. 3A is a front view of the first light flux controlling member 151, FIG. 3B is a bottom view, and FIG. 3C is a plan view. 4A is a side view of the first light flux controlling member 151, FIG. 4B is a cross-sectional view taken along the line AA shown in FIG. 3B, and FIG. 4C is a cross-sectional view taken along the line BB shown in FIG. 3B. FIG.

  As shown in FIGS. 3 and 4, the first light flux controlling member 151 has an incident surface 153, two total reflection surfaces 154, two light guides 155, two output surfaces 156, and a slit 157. The first light flux controlling member 151 is disposed so that the optical axis LA of the light emitting element 132 passes through the slit 157. Here, the “optical axis of the light emitting element” refers to the traveling direction of light at the center of the three-dimensional light flux from the light emitting element 132.

  The incident surface 153 allows a part of light emitted from the light emitting element 132 which is a point light source such as an LED to enter. The incident surface 153 is an inner surface of the first recess 158 formed at the center of the bottom surface (the surface on the light emitting element 132 side) of the first light flux controlling member 151. The shape of the first recess 158 is not particularly limited. The shape of the first recess 158 is preferably a curved surface that does not include an edge, such as a hemispherical shape or a semi-ellipsoidal shape.

  The two total reflection surfaces 154 are formed at positions facing the light emitting element 132 with the incident surface 153 interposed therebetween. The two total reflection surfaces 154 include the optical axis LA (see FIG. 2) of the light emitting element, are parallel to the slit 157, and are formed in plane symmetry with respect to a virtual plane perpendicular to the substrate 120. . Each of the two total reflection surfaces 154 transmits part of the light incident from the incident surface 153 in two directions (2) that are substantially perpendicular to the optical axis LA of the light emitting element 132 and the virtual plane and are opposite to each other Reflected in the direction of two light guides 155. That is, the two total reflection surfaces 154 reflect the reached light toward the two light guide portions 155.

  The shape of the total reflection surface 154 will be described with reference to FIG. 5A and 5B are diagrams showing a configuration of the light flux controlling member 10 used in a spotlight using a light emitting element as a light source. FIG. 5A is a perspective view of the light flux controlling member 10, and FIG. 5B is a cross-sectional view of the light flux controlling member 10. As shown in FIGS. 5A and 5B, the light flux controlling member 10 includes an incident surface 12 on which light emitted from the light emitting element is incident, and a total reflection surface 14 that totally reflects part of the light incident from the incident surface 12. And a light exit surface 16 that emits a part of the light incident from the light incident surface 12 and the light reflected by the total reflection surface 14. The incident surface 12 is an inner surface of a truncated cone-shaped recess formed at the bottom of the light flux controlling member 10. The total reflection surface 14 is a surface that extends from the outer edge of the bottom of the light beam control member 10 to the outer edge of the emission surface 16, and is a rotationally symmetric surface formed so as to surround the central axis of the light beam control member 10. The diameter of the total reflection surface 14 gradually increases from the incident surface 12 side (bottom side) toward the exit surface 16 side. The generatrix constituting the total reflection surface 14 is an arc-shaped curve convex outward. The exit surface 16 is a plane located on the opposite side of the entrance surface 12 (bottom) in the light flux controlling member 10.

  FIG. 5C is a diagram illustrating an optical path when the light flux controlling member 10 is used. As shown in FIG. 5C, the light emitted from the point light source arranged at a predetermined position enters the light flux controlling member 10 from the incident surface 12. A part of the light incident on the light flux controlling member 10 is emitted from the emission surface 16 to the outside as it is. The remaining part of the light incident on the light flux controlling member 10 is reflected by the total reflection surface 14 toward the emission surface 16 and emitted from the emission surface 16 toward the outside. Thus, the light emitted from the point light source is emitted from the emission surface 16 with the light distribution controlled.

  When this light flux controlling member 10 is divided into two along the line AA shown in FIG. 5B and the bottoms of the two divided pieces are joined together, a light flux controlling member 10 'shown in FIG. 5D is obtained. As shown in FIG. 5E, in such a light flux controlling member 10 ′, the light emitted from the point light source is reflected by the two total reflection surfaces 14 and travels in two directions opposite to each other. Become. The shape of the total reflection surface 154 of the first light flux controlling member 151 of the present embodiment is basically the same as the shape of the total reflection surface 14 of the light flux controlling member 10 'shown in FIG. 5D. In the following description, a portion in the vicinity of the boundary line between the two total reflection surfaces 14 indicated by reference numeral “18” in FIGS. 5D and 5E may be referred to as a “total reflection surface connection portion”. At this time, the boundary line of the total reflection surface 14 is an arc.

  The two light guides 155 are opposed to each other with the incident surface 153, the total reflection surface 154, and the total reflection surface 154 sandwiched therebetween (including the optical axis LA of the light emitting element and are plane-symmetric with respect to a virtual plane perpendicular to the substrate 120) ). The light guide unit 155 guides a part of the light incident from the incident surface 153 and the light reflected by the total reflection surface 154 in a direction away from the incident surface 153 and the total reflection surface 154 while emitting the light little by little to the outside. . The light guide unit 155 includes a light guide unit main body 160, a pair of reinforcing members 161, a pair of positioning projections 162, and four guide engagement grooves 164. Therefore, the outer surface of the light guide unit main body 160 functions as an emission surface 156 that emits the guided light to the outside.

  From the viewpoint of making the amount of light emitted from the emission surface 156 uniform, it is preferable that scatterers such as beads are dispersed in the light guide portion 155. Further, the light exit surface 156 may be subjected to light diffusion processing (for example, roughening processing).

  The shape of the light guide 155 is not particularly limited. In the present embodiment, the light guide unit 155 is a rod-shaped member. The two light guides 155 are respectively connected to the exit surface 16 of the light flux controlling member 10 'shown in FIG. 5D. The cross-sectional area of the light guide 155 in the minor axis direction is not particularly limited. In the present embodiment, the cross-sectional area in the short axis direction of the light guide 155 is the same at any position in the long axis direction of the light guide 155. In addition, the light guide 155 may be formed so that the cross-sectional area decreases as the distance from the total reflection surface 154 increases. When the cross-sectional area in the minor axis direction of the light guide 155 becomes smaller as the distance from the total reflection surface 154 decreases, the light guide 155 may be controlled by adjusting both the thickness and the width of the light guide 155, Control may be performed by adjusting only one of the widths. Further, the cross-sectional shape of the light guide unit 155 in the short axis direction is not particularly limited, and is appropriately selected according to the required light distribution characteristics. In the present embodiment, the cross-sectional shape of the light guide 155 in the minor axis direction is substantially semicircular.

  In addition, second concave portions 163 are formed on the bottom surface of the light guide body 160 (the surface on the light emitting element 132 side in the optical axis LA direction of the light emitting element). By forming the second recess 163, it is possible to suppress the occurrence of sink marks during injection molding and to reduce the manufacturing cost. The two second recesses 163 are both formed near the center of the first light flux controlling member 151, but are not in communication with the first recess 158.

  The size and shape of the second recess 163 can provide desired light distribution characteristics (light distribution characteristics that do not impair the effects of the present invention) and can ensure the strength required for the first light flux controlling member 151. There is no particular limitation. In the present embodiment, the shape of the second recess 163 in plan view is a trapezoid whose base is located on the light emitting element 132 side (see FIG. 3B). Further, the depth of the second recess 163 is not particularly limited, and can be set as appropriate. In addition, when shape | molding the 1st light beam control member 151 by injection molding, it is preferable to form the 2nd recessed part 163 in the site | part which may generate | occur | produce a sink.

  The reinforcing member 161 improves the strength of the first light flux controlling member 151. The position and shape of the reinforcing member 161 are not particularly limited as long as the function of the total reflection surface 154 of the first light flux controlling member 151 is not significantly impaired and the strength of the first light flux controlling member 151 can be improved. In the present embodiment, the reinforcing member 161 is disposed on the bottom surface (surface on the light emitting element 132 side) side of the first light flux controlling member 151, and connects the side surfaces of the light guide unit 155.

  The positioning convex portion 162 is a convex portion for positioning the light flux controlling member 150 with respect to the substrate 120. The positioning convex portion 162 is disposed on the back surface of the reinforcing member 161.

  The guide engaging groove 164 is disposed at a position farther from the light emitting element 132 than the reinforcing member 161 and the positioning convex portion 162. The guide engagement groove 164 positions the second light flux control member 152 with respect to the first light flux control member 151 by engaging an engagement protrusion 174 (see FIG. 6) of the second light flux control member 152 described later. It is a groove for.

  The slit 157 is a through-hole disposed along the boundary line of the total reflection surface 154 between the two total reflection surfaces 154. The slit 157 advances another part of the light emitted from the light emitting element 132 in the direction along the optical axis LA as it is. The shape and position of the slit 157 between the total reflection surfaces 154 are not particularly limited. In the present embodiment, the slit 157 causes the light emitted from the light emitting element 132 to travel as it is at an angle of at least 45 ° with respect to the optical axis LA of the light emitting element 132 in the cross section including the virtual plane. A slit 157 is disposed. The amount of light emitted from the slit 157 does not change greatly even if the light emitted at an angle of more than 45 ° with respect to the optical axis LA of the light emitting element 132 is allowed to travel as it is. The length (width) in the major axis direction of the slit 157 is not particularly limited. What is necessary is just to set suitably according to the light quantity of the light which advances the slit 157. FIG.

  As shown in FIG. 2, the second light flux controlling member 152 is disposed so as to cover at least the slit 157, is emitted from the light emitting element 132, and travels as it is without entering the first light flux controlling member 151 (slit 157) is diffused and transmitted. The shape of the second light flux controlling member 152 is not particularly limited as long as the above function can be exhibited. Examples of the shape of the second light flux controlling member 152 include a semi-cylindrical shape and a bell-like shape (inverted U shape). In the present embodiment, the second light flux controlling member 152 has a bell-like shape.

  6 and 7 are diagrams showing the configuration of the second light flux controlling member 152. FIG. 6A is a front view of the second light flux controlling member 152, FIG. 6B is a plan view, and FIG. 6C is a bottom view. 7A is a side view of the second light flux controlling member 152, FIG. 7B is a cross-sectional view taken along line AA shown in FIG. 6B, and FIG. 7C is a cross-sectional view taken along line BB shown in FIG. 6B. FIG. As shown in FIGS. 6 and 7, the second light flux controlling member 152 has a semi-cylindrical portion 171 and two side wall portions 172.

  The semi-cylindrical portion 171 is disposed in the vicinity immediately above the total reflection surface 154. On the inner surface of the semi-cylindrical portion 171, a plurality of concave stripes (diffuse transmission portions) 173 are formed. The plurality of concave stripes 173 are arranged in a semicircular shape in a direction perpendicular to the axial direction of the second light flux controlling member 152. Here, the “axis of the second light flux controlling member 152” refers to the axis of the semi-cylindrical portion 171.

  The two side wall portions 172 are respectively connected to the side edges of the semi-cylindrical portion 171. A plurality of concave stripes 173 (diffuse transmission portions) are formed in the central portion of the inner surface of the side wall portion 172. The plurality of concave stripes 173 are linearly arranged in a direction perpendicular to the axial direction of the second light flux controlling member 152. In addition, the plurality of recesses 173 disposed in the semi-cylindrical portion 171 and the plurality of recesses 173 disposed in the side wall portion 172 corresponding to the plurality of recesses 173 disposed in the semi-cylindrical portion 171 are respectively connected. Are arranged as follows. The concave stripe 173 allows the transmitted light to pass through while diffusing. The cross-sectional shape of the recess 173 is not particularly limited. Examples of the cross-sectional shape of the concave stripe 173 include a semicircular shape and a triangle. In the present embodiment, the cross-sectional shape of the recess 173 is a semicircular shape. Each recess 173 may have the same shape or a different shape. In the present embodiment, each recess 173 is formed in the same shape.

  In addition, four engagement protrusions 174 are arranged inside the both end portions of the side wall portion 172. The four engaging protrusions 174 engage the four guide engaging grooves 164 disposed on the first light flux controlling member 151, thereby positioning the second light flux controlling member 152 on the first light flux controlling member 151. A projection 175 for positioning and fixing the second light flux controlling member 152 to the substrate 120 is disposed at the end of the side wall 172 where the semi-cylindrical part 171 is not connected. The protrusion 175 of the second light flux control member 152 is engaged with the guide engagement groove 164 of the first light flux control member 151 fixed to the substrate 120 while the protrusion 175 of the second light flux control member 152 is engaged with the guide 120. The second light flux controlling member 152 can be fixed to the substrate 120 and the first light flux controlling member 151 by being fitted into the engaging recess (not shown).

  A part of the light emitted from the light emitting element 132 enters the first light flux controlling member 151 from the incident surface 153. A part of the light incident on the light flux controlling member 150 (light emitted at a small angle with respect to the optical axis LA of the light emitting element 132) is reflected toward the light guide unit 155 on the total reflection surface 154. Further, another part of the light incident on the first light flux controlling member 151 (light emitted at a large angle with respect to the optical axis LA of the light emitting element 132) reaches the light guide 155 as it is. Further, the light emitted from the light emitting element 132 and along the optical axis LA of the light emitting element 132 passes through the slit 157 as it is.

  The light incident on the light guide unit 155 is guided toward the end of the light guide unit 155 while being gradually emitted from the emission surface 156 to the outside. As a result, light is emitted substantially uniformly from the entire outer surface of the light flux controlling member 150. On the other hand, the light that has passed through the slit 157 and the light emitted from other than the center of the light emitting element 132 reach the second light flux controlling member 152. The light incident on the second light flux controlling member 152 is transmitted through the light flux controlling member 150 while being diffused by the plurality of concave stripes 173. The light emitted from the emission surface 156 of the light flux controlling member 150 passes through the air layer and reaches the inner surface of the cover 140. The light reaching the inner surface of the cover 140 passes through the cover 140 while being diffused. As a result, light is emitted substantially uniformly from the entire outer surface of the cover 140. In this manner, the light emitted from the light emitting element 132 that is a point light source can be converted into linear light by the light flux control member 150.

(Simulation 1)
In the simulation 1, the luminance distribution on the outer surface of the cover 140 of the lighting apparatus 100 according to the present embodiment was simulated. For comparison, the luminance distribution on the outer surface of the cover of the illumination device (see FIG. 8A) according to the comparative example having the light flux controlling member according to the comparative example not having the slit 157 was also simulated.

  FIG. 8B is a diagram for explaining the simulation conditions of the luminance distribution when the illumination device 100 is observed from the front. As shown in FIG. 8B, in this simulation, a plurality of light emitting elements 132 (white LEDs) are arranged in a line on the substrate 120 so that the center-to-center distance (P) is 48 mm, and the light emitting elements 132 are placed on the light emitting elements 132. A light flux controlling member 150 having a length of 38 mm was disposed. Further, the distance from the light emitting surface of the light emitting element 132 to the outer surface of the cover 140 was 16 mm, the height of the light flux controlling member 150 was 6.7 mm, and the inner diameter of the cover 140 was 24 mm. In this simulation, an example in which only one light emitting element 132 is turned on is shown.

FIG. 8C is a graph showing a simulation result. The horizontal axis in FIG. 8C indicates the distance (mm) from the optical axis LA of the light emitting element 132 adjacent to the simulated light emitting element 132 (light flux controlling member 150). The vertical axis represents luminance (cd / m ² ). The solid line in FIG. 8C shows the simulation result when the light flux controlling member 150 according to the present embodiment is used, and the broken line shows the simulation result when the light flux controlling member of the comparative example is used.

  As shown in FIG. 8B, the illumination device 100 according to the present embodiment using the light flux controlling member 150 having the slit 157 uses the light flux controlling member of the comparative example (see FIG. 8A) that does not have the slit 157. Compared with the illumination device of the comparative example, the brightness on the outer surface of the cover 140 immediately above the slit 157 was high. Further, the luminance of the light emitted from the light flux controlling member 150 was lower as the distance from the intersection between the optical axis LA of the light emitting element 132 and the outer surface of the cover 140 was increased.

(Simulation 2)
Next, the effect of the width of the slit 157 on the luminance distribution on the cover 140 was simulated. For the simulation, four types of first light flux controlling members 151 having a slit 157 width of 0.05 mm, 0.1 mm, 0.3 mm, and 1.0 mm were used. In this simulation, the brightness distribution of the outer surface of the cover 140 irradiated with only the light passing through the slit 157 was examined without using the second light flux controlling member 152. Other simulation conditions are the same as those of simulation 1.

FIG. 9A is a graph showing the simulation results, and FIG. 9B shows the distance from the center of the slit 157 in the major axis direction of the light flux controlling member 150 (the arrangement direction of the light emitting elements 132) and the luminance on the outer surface of the cover 140. It is a graph which shows the relationship. The horizontal axis in FIG. 9A indicates the distance (mm) from the center of the slit 157 (the center of the first light flux controlling member 151), and the horizontal axis in FIG. 9B indicates the slit width (mm). The vertical axis in FIGS. 9A and 9B indicates the luminance (cd / m ² ) on the outer surface of the cover 140. The broken line in FIG. 9A shows the result when the first light flux controlling member 151 having the width of the slit 157 of 0.05 mm is used, and the one-dot chain line shows the first light flux controlling member 151 having the width of the slit 157 of 0.1 mm. The results when used are shown. The two-dot chain line shows the results when the first light flux controlling member 151 with the slit 157 width of 0.3 mm is used, and the solid line shows the width of the slit 157 with 1.0 mm. The result at the time of using the 1st light beam control member 151 of this is shown.

  As shown in FIG. 9A, it can be seen that the light passing through the slit 157 increases as the width of the slit 157 increases. Further, as shown in FIG. 9B, it was found that there is a correlation between the width of the slit 157 and the amount of light passing through the slit 157.

(Simulation 3)
Next, the effect of the width of the slit 157 on the luminance distribution on the outer surface of the cover 140 was simulated using the illumination device 100 having the light flux controlling member 150 according to the present embodiment. Moreover, it simulated about the illuminating device which has the light beam control member (refer FIG. 10A) by which the slit was block | closed as a comparative example. Other simulation conditions are the same as those of simulation 1.

FIG. 10B is a graph showing a simulation result, and FIG. 10C shows the distance from the center of the slit 157 in the major axis direction (the arrangement direction of the light emitting elements 132) of the light flux controlling member 150, and the amount of light passing through the slit 157. It is a graph which shows the relationship. The horizontal axis in FIGS. 10B and 10C indicates the slit width (mm), and the vertical axis in FIGS. 10B and 10C indicates the luminance (cd / m ² ) on the outer surface of the cover 140. The thick solid line in FIG. 10B shows the result when the first light flux controlling member 151 having the slit 157 width of 0.05 mm is used, and the thick broken line shows the first light flux controlling member 151 having the slit 157 width of 0.1 mm. The thick one-dot chain line shows the result when the first light flux controlling member 151 having the slit 157 width of 0.3 mm is used, and the thick two-dot chain line shows the width of the slit 157. Shows the result when the first light flux controlling member 151 of 1.0 mm is used. The thin solid line in FIG. 10B shows the result when the first light flux control member 151 having a flat portion width of 0.3 mm is used, and the thin broken line shows the first light flux control member 151 having a flat portion width of 0.6 mm. The thin dot-and-dash line shows the result when the first light flux controlling member 151 having a flat portion width of 1.2 mm is used.

  As shown in FIG. 10B, it can be seen that the light passing through the slit 157 increases as the width of the slit 157 increases. Further, as shown in FIG. 10C, it has been found that there is a correlation between the width of the slit 157 and the amount of light passing through the slit 157.

  As shown in FIG. 8B, lighting device 100 according to the present embodiment has a plurality of light emitting devices (light flux controlling member 150 and light emitting element 132) arranged on substrate 120. As shown in FIG. 8C, when only one light emitting device 130 is used, the luminance of light on the outer surface of the cover 0 decreases as the distance from the center of the light emitting device 130 increases. Therefore, in order to emit light uniformly from the entire cover 140, it is necessary to partially overlap the light emitted from the light emitting device 130 with the light emitted from the adjacent light flux controlling member 150. In this way, in order to partially overlap the light and emit light uniformly as the entire lighting device 100, the brightness A at the intersection of the optical axis LA of the light emitting element 132 and the outer surface of the cover 140, and the cover It is preferable that the luminance B at the midpoint of the two intersections adjacent to each other on the outer surface 140 satisfies “luminance A <1.7 × luminance B”. More specifically, it is preferable that (luminance A + luminance C × 2) ≈ (2 × luminance B) and 1.7 × luminance B ≦ (luminance A + luminance C × 2) ≦ 2.3 × luminance B are satisfied. . Here, “luminance C” refers to the luminance at the intersection of the optical axis LA of the light flux controlling member 150 adjacent to the light flux controlling member 150 showing the luminance A and the outer surface of the cover 140. Even if the distance between the centers of the light emitting elements 132, the spatial distance, the material of the light flux controlling member 150, and the diffusion cover are appropriately changed, if the luminance A, luminance B, and luminance C are within the aforementioned ranges, the light is emitted from the lighting device 100. The uniformity of the brightness of the light can be ensured.

  In addition, when the cross section of the some groove 173 is a triangle, the groove 173 has a 1st inclined surface and a 2nd inclined surface.

(effect)
In order to solve the problem in the LED lighting device described in Patent Document 1, the present inventor first produced a light flux controlling member having the above-described reflecting surface 154. With this light flux controlling member, it was possible to solve the problem that the upper part of the light emitting element 132 was too bright, but this time the light emitting element 132 becomes brighter and the upper part of the light emitting element 132 becomes darker. was there.

  In view of this, the present inventor has provided the slit 157 between the reflecting surfaces 154 so that the light emitted from the light emitting element 132 is allowed to travel through the slit 157 as it is. Thereby, in lighting apparatus 100 according to the present embodiment, the portion directly above light emitting element 132 can be brightened, and uneven brightness in the arrangement direction of light emitting elements 132 can be reduced. Further, by arranging the second light flux controlling member 152 having the concave stripe (diffuse transmission part) 173 on the optical path of the light passing through the slit 157, the amount of light emitted from the effective light emitting region of the illumination device 100 is made uniform. can do.

(Modification)
11 and 12 are diagrams showing a configuration of a light emitting device 130 according to a modification of the embodiment. FIG. 11A is a perspective view showing the arrangement of the first light flux controlling member 151 according to the modification, and FIG. 11B is a state in which the second light flux controlling member 152 is combined with the first light flux controlling member 151 shown in FIG. 11A. FIG. 12A is a perspective view showing the light flux controlling member 150 in a state where the light guide unit 155 is connected in a plane perpendicular to the optical axis LA of the light emitting element 132, and FIG. 12B is a plane including the optical axis LA of the light emitting element 132. It is a perspective view which shows the light beam control member 150 of the state which the light guide part 155 connected in FIG.

  As shown in FIGS. 11A and 11B, in light flux controlling member 150 according to the modification of Embodiment 1, a plurality of light flux controlling members 150 (first light flux controlling member 151 and second light flux controlling member 152) are arranged in a row. May be. Moreover, as shown in FIGS. 12A and 12B, in the light flux controlling member 150 according to the modification of the first embodiment, the end surfaces on the opposite side to the total reflection surface 154 of the two light guide portions 155 are combined. As a whole, it may be formed in an annular shape.

  Since the lighting device of the present invention can be used in place of a fluorescent tube or the like, it can be widely applied to various lighting devices.

DESCRIPTION OF SYMBOLS 100 Illuminating device 110 Frame 120 Board | substrate 130 Light-emitting device 132 Light-emitting device 140 Cover 150 Light flux control member 151 1st light flux control member 152 2nd light flux control member 153 Incident surface 154 Total reflection surface 155 Light guide part 156 Output surface 157 Slit 158 1st Concave portion 160 Introducing portion main body 161 Reinforcing member 162 Positioning convex portion 163 Second concave portion 164 Guide engaging groove 171 Semi-cylindrical portion 172 Side wall portion 173 Concave strip 174 Engaging projection 175 Protruding portion

Claims (5)

A light flux controlling member having a first light flux controlling member and a second light flux controlling member, for controlling the light distribution of the light emitted from the light emitting element,
The first light flux controlling member is
An incident surface on which a part of the light emitted from the light emitting element is incident;
Two directions which are formed at positions facing the light emitting element across the incident surface, and a part of the light incident on the incident surface is substantially perpendicular to the optical axis of the light emitting element and opposite to each other Two total reflection surfaces to be reflected,
A slit that is disposed between the two total reflection surfaces and directly advances another part of the light emitted from the light emitting element in a direction along the optical axis;
Two light guide portions disposed at positions facing each other across the incident surface, the total reflection surface, and the slit, and a part of the light incident on the incident surface and the light reflected by the total reflection surface; ,
An emission surface that is formed on the outer surface of the light guide unit and emits the light guided by the light guide unit to the outside;
Including
The second light flux controlling member is disposed so as to cover the slit, and includes a diffusive transmitting portion that diffuses and transmits light that has traveled through the slit.
Luminous flux control member.   The slit, in a cross section including a boundary portion between the two total reflection surfaces, directly proceeds the light emitted from the light emitting element at an angle of at least 45 ° with respect to the optical axis of the light emitting element. The light flux controlling member according to claim 1. The light flux controlling member according to claim 1 or 2, wherein the light emitting element and the optical axis of the light emitting element are disposed so as to pass through the slit.
A light emitting device. A plurality of light emitting devices according to claim 3;
A cover disposed via an air layer for each of the plurality of light emitting devices so as to cover the plurality of light emitting devices;
A lighting device. The luminance A at the intersection between the optical axis of the light emitting element and the outer surface of the cover and the luminance B at the middle point between two adjacent points on the outer surface of the cover satisfy the following expression (1). The lighting device according to claim 4.
Luminance A <1.7 × Luminance B (1)