JP2014165021A - Illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination device which is thin and which can achieve narrow orientation.SOLUTION: An illumination device 100 includes: a plurality of light emitting elements 22; a light guide plate 40 for guiding light emitted from the plurality of light emitting elements; and a disk-like light condensing cover 60 arranged on a principal surface 410 side of the light guide plate. The light guide plate has a plurality of concave-shaped reflection parts 44 recessing a rear surface which is at the back of a principal surface for changing an optical path of the guided light at a plurality of places toward the principal surface. The light condensing cover has a plurality of lens parts 61 arranged by keeping an optically opposing relation individually with each of the plurality of concave-shaped reflection parts, and condensing the reflection light from each of the concave-shaped reflection parts in a main emission direction vertical to the principal surface. The individual optically opposing relation between the concave-shaped reflection parts 44 and the lens parts 61 is deviated in such a manner that a center position of the concave-shaped reflection part comes closer to the center of the light guide plate than a central axis of the lens part, and also, adjustment is made so that the deviation amount of the ones nearer to a peripheral edge of the light guide plate is larger than the deviation amount of ones existing in the center of the light guide plate.

Description

  The present invention relates to an illumination device including a semiconductor light emitting element such as an LED (light emitting diode) as a light source. The present invention particularly relates to a concentrating illumination device.

In recent years, from the viewpoint of energy saving, a lighting device using a semiconductor light emitting element as a light source such as a highly efficient LED and a long life has been developed. Particularly in recent years, downlights and spotlights using a wide light emitting area of LED light emitting modules have been proposed. For example, Patent Document 1 proposes a concentrating illumination device 800 including an LED light emitting module having a planar light emitting unit and a Fresnel lens. FIG. 27 is a cross-sectional view showing an internal configuration of a conventional lighting device 800. The lighting device 800 includes a housing 801, a light emitting module 802 housed inside the housing 801, and a Fresnel lens 803 disposed on the optical path. The light emitting module 802 includes a plate-like substrate 8020, a light emitting element (LED) 8021 mounted on the substrate 8020, and a phosphor layer 8022 disposed in front of the light emitting element 8021. By supplying power to the lighting device 800, each light emitting element 8021 is turned on. Lights L ₁ and L ₂ emitted from the light emitting element 8021 pass through the Fresnel lens 803. Lights L ₁ and L ₂ are adjusted to parallel light by a Fresnel lens 803 and irradiated outside.

JP 2012-114022 A

However, in the conventional condensing type illumination device, it is necessary to secure an optical path having a predetermined length between the light source and the lens in order to condense at a constant light distribution angle. As a result, it has been difficult to simultaneously realize the thinning and narrow orientation of the lighting device.
For example, in the conventional illumination device 800 described in Patent Document 1, when the 1/2 beam angle, which is one of the indices for evaluating the orientation, is 45 °, the optical path from the light emitting part of the light source to the lens surface A length of 27 mm was required. On the other hand, when the optical path length was shortened to 10 mm, the 1/2 beam angle was 100 °, and further improvement was necessary to achieve both thinness and narrow orientation.

  The present invention has been made in view of the above problems, and an object thereof is to provide a lighting device that is thin and capable of realizing narrow orientation.

In order to achieve the above object, an illumination device according to an aspect of the present invention includes a light emitting unit in which a plurality of light emitting elements are arranged in a ring shape on a substrate, and a light introducing unit facing a light emitting element array of the light emitting unit. A light guide plate having a disk-shaped in-ring light guide that guides the introduced light in the direction toward the inner side of the ring, and a disk-shaped light collecting cover disposed on one main surface side of the light guide plate;
The light guide plate has a plurality of concave reflectors recessed in the back surface facing away from the main surface in order to change the optical path of the guided light toward the main surface at a plurality of locations. The condensing cover is disposed in an optically opposing relationship with each of the plurality of concave reflecting portions and reflects light from each concave reflecting portion in a main emission direction perpendicular to the main surface. A plurality of condensing lens portions, and the individual optical facing relationship between the concave reflecting portion and the lens portion is such that the center position of the concave reflecting portion is the lens portion of the concave reflecting portion and the lens portion in the facing relationship. It is shifted so that it is closer to the center of the light guide in the ring than the center axis, and the amount of shift closer to the periphery of the light guide in the ring is adjusted to be larger than that in the center of the light guide in the ring. It is characterized by being.

In another aspect, the amount of deviation may be gradually increased from the center of the in-ring light guide portion toward the periphery.
Further, in another aspect, the concave reflecting portion is disposed on each circumference of a first concentric circle having a plurality of circumferences forming a first interval in the radial direction of the in-ring light guide portion, and the lens. The portion is arranged on each circumference of a second concentric circle having a plurality of circumferences forming a second interval in the radial direction of the light collecting cover, and the center position of the first concentric circle and the second concentric circle The center position may overlap in the main emission direction, and the first interval may be smaller than the second interval.

In another aspect, the first interval may be not less than 1.5 times and not more than 2.5 times the thickness of the light guide plate.
In another aspect, each of the concave reflecting portions has a conical shape with the top facing the main surface side, and the concave portion near the periphery inside the ring is the concave reflecting portion near the center inside the ring. The cone may have a higher height than the portion.

  In another aspect, the plurality of lens portions are arranged so as to individually overlap each of the plurality of concave reflection portions when the light collection cover is viewed in plan. May be.

  In the lighting device according to one embodiment of the present invention, the optical path from the light-emitting element to the lens portion can be shortened by the above structure. By shortening the optical path, the lighting device can be made thinner. Furthermore, the alignment characteristics of the light emitted from different positions of the light collecting cover can be made different so that the unevenness in each illuminance distribution can be superimposed on each other. Thereby, in the condensing type illuminating device, it is possible to improve the drop in illuminance near the orientation angle of 0 ° and realize narrow orientation.

It is sectional drawing which shows the structure of the illuminating device 900 which is an assumed illuminating device. (A) is sectional drawing of the whole illuminating device 900. FIG. (B) is an expanded sectional view of the area | region A of (a). It is explanatory drawing of the condensing principle in the light-guide plate 40 and the condensing cover 60 in the illuminating device 900 which is assumed illuminating device, (a) vicinity of the center part of the condensing cover 60, (b) is a left end periphery part, (C) shows the peripheral portion at the right end, and (d) shows the total sum. It is a partial cross section figure which shows the structure and installation example of the illuminating device 100 which concerns on embodiment. It is a figure which shows the external appearance structure and internal structure of the lighting fixture 1. FIG. 1 is a plan view of a lighting fixture 1. FIG. It is an exploded view (assembly drawing) which shows the internal structure of the lighting fixture 1. FIG. 2 is a cross-sectional view showing an internal configuration of the lighting fixture 1. FIG. (A) is a top view of the reflection member 30 of the lighting fixture 1, (b) is sectional drawing cut | disconnected by the cross section AA in (a), (c) is a back view. (A) is a perspective view which shows the structure of the light-guide plate 40 of the lighting fixture 1. FIG. (B) is the E section enlarged view in (a). (A) is an expanded sectional view which shows the B section in FIG. 7, (b) is an expanded sectional view which shows the F section in (a). It is an expanded sectional view which shows the C section in FIG. FIG. 4 is a schematic diagram showing a cross-sectional shape of a concave reflecting portion 44 in the light guide plate 40 of the lighting fixture 1. (A) is a top view of the condensing cover 60 of the lighting fixture 1, (b) is the G section enlarged view in (a), (c) is a side view, (d) is a back view. FIG. 4 is a schematic diagram illustrating a cross section of a lens portion 61 in a light collection cover 60 and a concave reflection portion 44 in a light guide plate 40 of the lighting fixture 1. FIG. 6 is an explanatory diagram showing the arrangement in the XY direction of the concave reflecting portion 44 of the light guide plate 40 of the lighting fixture 1 and the lens portion 61 of the light collecting cover 60. It is an expanded sectional view which shows the D section in FIG. It is explanatory drawing of the condensing principle in the light-guide plate 40 and the condensing cover 60 in the illuminating device 100, (a) vicinity of the center part of the condensing cover 60, (b) is a left end periphery part, (c) is a right end periphery part. , (D) indicates the total sum. It is a schematic diagram showing a masking pattern 700 used for calculation of orientation characteristics for each position in the lens region 63 of the illumination device 100. The characteristic view which shows the calculation result of the orientation characteristic of the illuminating device 100, (a) is illumination light from φ20mm range from the center of the inner ring 41 of the light guide plate 40, and (b) is 10mm away from the center of the inner ring 41. Illumination light from a φ20 mm range centered at is (c) is illumination light from a φ20 mm range centered at a position 20 mm away, and (d) is an orientation of illumination light from a φ20 mm range centered at a position 30 mm away. It is a characteristic. It is a characteristic view which shows the orientation characteristic of the light irradiated from the condensing cover 60 whole surface in the illuminating device 100. FIG. FIG. 11 is a characteristic diagram showing a change in alignment characteristics of light irradiated from the entire surface of the light collecting cover 60 when the _P44 ratio is changed in the pitch of the concave reflecting portion 44 with respect to the pitch P ₆₁ of the lens portion 61 in the illumination device 100. . It is a characteristic view which shows the calculation result of the orientation characteristic of the illuminating device 100. FIG. It is a characteristic view which shows the calculation result of the orientation characteristic of the comparative example of the illuminating device 100. It is a characteristic view which shows the calculation result of the orientation characteristic of the illuminating device 100. FIG. FIG. 9 is an enlarged cross-sectional view showing the same part as part D of FIG. 7 related to lighting device 100 in lighting device 100A according to a modified example. It is explanatory drawing of the condensing principle in the light-guide plate 40 in the illuminating device 100A which concerns on a modification, and the condensing cover 60, (a) vicinity of the center part of the condensing cover 60 in a comparative example, (b) is the center in a modification. (C) shows the state of the peripheral part in the modification. It is sectional drawing which shows the internal structure of the conventional illuminating device 800. FIG.

≪Background to the form for carrying out the invention≫
In the lighting device 900 described in Patent Document 1, the ½ illuminance angle, which is one measure indicating the degree of light distribution, was 45 °. It is desired that the light condensing characteristics be further improved as a condensing type lighting device. Here, the ½ illuminance angle refers to an angle formed by a line connecting the point where the illuminance is ½ of the illuminance directly below the light source, the center of the light source, and the vertical direction line of the light source center.

  On the other hand, the inventors assumed the configuration of the illumination device 900 shown in the cross-sectional view of FIG. FIG. 1 is a cross-sectional view illustrating a configuration of an illumination device 900 that is an assumed illumination device. (A) is sectional drawing of the whole illuminating device 900. FIG. (B) is an expanded sectional view of the area | region A of (a). As illustrated in FIG. 1A, the lighting device 900 is disposed on a base 910, a mounting substrate 920 disposed on the base 910, a reflecting member 930 disposed on the mounting substrate 920, and the reflecting member 930. And a light guide plate 940. Furthermore, the illumination device 900 includes a light collecting cover 960 disposed on the light guide plate 940 and a diffusion cover 950 that covers the periphery of the light collecting cover 960. The mounting substrate 920 includes a plurality of semiconductor light emitting elements (LEDs) 922 mounted on the substrate surface. As shown in FIG. 1B, which is an enlarged cross-sectional view of region A in FIG. 1A, the light guide plate 940 has a conical concave reflection formed by recessing the back surface facing the reflecting member 930 in the thickness direction. A plurality of portions 944 are provided. The condensing cover 960 includes a plurality of minute lens portions 961 at positions overlapping with the respective concave reflection portions 944.

In the illumination device 900, as shown in FIG. 1B, the light L ₃ and L ₄ incident on the light guide plate 940 from the light emitting element 922 is reflected to the lens unit 961 side by the inclined surface of the concave reflection unit 944. The lights L ₃ and L ₄ are condensed by the lens unit 961 directly above the concave reflection unit 944 and become illumination light. In the lighting device 900, parallel light can be incident on the lens unit 961 from a short distance by using the light guide plate 940 and the concave reflection unit 944. Accordingly, the minute lens portion 961 is brought close to each concave reflection portion 944 to prevent the light from diffusing, and a good light collecting effect can be expected.

  By the way, in the illuminating device 900, after the light reflected from the concave reflection part 944 is condensed by the lens part 961 which has an optical facing relationship, it is irradiated on a target surface. At that time, light emitted from the plurality of lens portions 961 is superimposed on the target surface and irradiated. Therefore, there is a characteristic that the illuminance distribution formed by the individual optical system including the concave reflection portion 944 and the lens portion 961 affects the illuminance distribution of the entire lighting device 900.

  FIGS. 2A and 2B are explanatory views of the light collecting principle of the light guide plate 940 and the light collecting cover 960 in the lighting device 900 that is an assumed lighting device, where FIG. 2A is near the center of the light collecting cover 960 and FIG. The left end peripheral part, (c) shows the right end peripheral part, and (d) shows the total sum. As shown in FIG. 2A, the emitted light from the light emitting element 922 is reflected in the direction of the exit surface 9410 by the concave reflecting portion 944 formed on the back surface 9411 of the light guide plate 940. At this time, the reflecting surface of the concave reflecting portion 944 is at a position shifted from the central axis 944A, and light reflected from the reflecting surface, for example, light of q1, q2, q3, q4 or r1, r2, r3, r4 is condensed. After entering the cover 960, the lens unit 961 converts the light into a light inclined with respect to the front in the main emission direction. For this reason, the intensity peak of the light emitted from the circularly concave concave reflecting portion 944 is formed at a position slightly deviated from the orientation angle of 0 °. For example, when the diameter of the bottom surface of the cone in the concave reflecting portion 944 is 0.8 mm, the peak of the intensity of the emitted light occurs at an orientation angle of about ± 5 °.

Here, in the vicinity of the central portion of the light collecting cover 60, the distance from the light emitting element 922 is substantially equal on the left and right, and the light incident on the concave reflecting portion 44 is substantially equal on the left and right. Therefore, two equal illuminance peaks are formed on the target surface. The peak-to-peak distance X ₀ is, for example, several tens of centimeters on the symmetry plane located at a distance Z ₂₀₀₀ of about 2 m.
Next, as shown in FIG. 2B, the light reflected by the concave reflecting portion 944 of the light guide plate 940 located around the left end portion of the light collecting cover 960 is also collected in the same manner. At this time, the distance from the light emitting element 922 is different on the left and right around the light collecting cover 960, the distance from the left light emitting element 922 is short, and the distance from the right light emitting element 922 is large. Therefore, the light entering the concave reflecting portion 944 from the left side has a larger luminous flux than the light entering from the right side, and the peak of illuminance is only approximately + 5 ° on the target surface based on t1, t2, t3, and t4. Is formed.

  Further, as shown in FIG. 2C, the light reflected by the concave reflecting portion 944 of the light guide plate 940 located around the right end portion of the light collecting cover 960 is also collected in the same manner. At this time, the distance from the right light emitting element 922 is small near the right end portion of the light collecting cover 960, and the distance from the left light emitting element 922 is large. Therefore, the light entering the concave reflecting portion 944 from the right side has a larger luminous flux than the light entering from the left side, and has an illuminance of only about −5 ° on the target surface based on u1, u2, u3, u4. A peak is formed.

When the illuminance distribution shown in FIGS. 2 (a) or 2 (c) is superimposed, the illumination device 900 causes a drop in illuminance near the orientation angle of 0 ° as shown in FIG. 2 (d). Two large illuminance peaks that are equal are formed. This phenomenon is called ring-shaped illuminance distribution, and there is room for further improvement in the lighting device 900.
In view of this, the inventors have intensively studied a technique for optimizing the illuminance distribution on the irradiation target surface in a configuration including a light collecting cover having a plurality of lens portions and a light guide plate having a plurality of concave reflection portions. The inventors have arrived at the lighting device according to the embodiment of the present invention.

Hereinafter, an illumination device according to an embodiment of the present invention will be described with reference to the drawings.
<< Embodiment >>
<Configuration of lighting apparatus 100>
FIG. 3 is a partial cross-sectional view showing a configuration and an installation example of lighting apparatus 100 according to the embodiment. The illumination device 100 has a disk shape parallel to the XY plane, and the Z direction is the main emission direction. As shown in FIG. 3, the lighting device 100 includes a lighting fixture 1, a leaf spring-like retaining member 3, and a power supply unit 4 that lights the lighting fixture 1. The luminaire 1 is electrically connected to the power supply unit 4 by wiring 23. The latch member 3 is attached to the base 10 on the back side of the lighting fixture 1. In the embodiment, the lighting device 100 is a downlight with an outer diameter of about 136 mm embedded in the ceiling.

When installing the lighting device 100, the power supply unit 4 is placed on the back surface 2 b of the ceiling 2 through the through hole 2 a provided in the ceiling 2. The lighting fixture 1 is arrange | positioned with respect to the through-hole 2a so that the base 10 may be accommodated. At this time, the latch member 3 is latched around the periphery of the through hole 2a. Accordingly, the lighting device 100 can be installed on the ceiling 2.
FIG. 4 is a diagram illustrating an external configuration and an internal configuration of the lighting fixture 1 according to the embodiment. FIG. 5 is a plan view of the luminaire 1. As shown in FIGS. 4 and 5, the luminaire 1 has a disc-shaped light collection cover 60 centered around the base 10 and the point O, and an annular diffusion cover 50 provided around the luminaire 1. Consists of. A wiring 23 is extended from the notch 16 of the base 10 to the outside. The point O constitutes the center of the luminaire 1 in the XY plane.

Note that dotted lines in FIG. 4 indicate the positions of the built-in mounting substrate 20, light emitting element 22, and substrate body 21.
<Configuration of lighting apparatus 1>
FIG. 6 is an exploded view (assembly drawing) showing an internal configuration of the lighting fixture 1 according to the embodiment. FIG. 7 is a cross-sectional view illustrating an internal configuration of the lighting fixture 1 according to the embodiment. As shown in FIGS. 6 and 7, the lighting fixture 1 includes a base 10, a mounting substrate 20, a reflection member 30, a light guide plate 40, a diffusion cover 50, and a light collection cover 60. The lighting fixture 1 has a disk-like overall shape. Each outer peripheral shape of the base 10, the mounting substrate 20, the reflecting member 30, the light guide plate 40, and the diffusion cover 50 is formed in a circle according to the overall shape of the lighting fixture 1.

The light guide plate 40 and the light collecting cover 60 are in contact with each other, and the maximum thickness of the light collecting cover 60 is 2.5 mm with respect to the thickness of the light guide plate 40 being 1.5 mm. If the thickness of the light guide plate 40 is further reduced, the thickness of the light collecting cover 60 can be reduced in proportion thereto.
(Base 10)
The base 10 is made of a material having excellent heat dissipation characteristics, for example, a metal material such as an aluminum die-cast material. The base 10 has a main body part 11 having a two-stage bottom structure with a deep center side and a shallow peripheral edge side, and a flange part 12 erected around the main body part 11 (FIG. 6). The flange portion 12 has a notch portion 16.

The main body 11 has a disk-shaped inner bottom 13 with a deep bottom, a shallow bottom, an inner bottom 13 and a side wall 14 erected on the periphery of the inner bottom 13, And an annular outer bottom portion 15 disposed around the portion 14.
The mounting substrate 20 and the reflecting member 30 are sequentially stacked on the inner bottom portion 13. An annular outer peripheral portion 43 of the light guide plate 40 is placed on the outer bottom portion 15.

The flange portion 12 is joined to the side wall portion 52 of the diffusion cover 50 using, for example, an adhesive or a seal member, in the vicinity of the top portion in the Z direction.
(Mounting board 20)
The mounting substrate 20 includes an annular substrate body 21, a plurality of light emitting elements 22 mounted on the surface of the substrate body 21 (an upper surface facing the reflecting member 30 in FIG. 6), and a wiring 23 to form a light emitting unit. To do.

The substrate body 21 has, for example, a two-layer structure in which an insulating layer made of a ceramic material or a heat conductive resin and a metal layer made of aluminum or the like are laminated. A wiring pattern (not shown) for electrically connecting the light emitting element 22 and the wiring 23 is formed on the surface of the substrate body 21. The outer diameter of the substrate body 21 is substantially matched with the inner diameter of the side wall portion 14.
The light emitting element 22 uses an LED element as an example. As shown in an enlarged sectional view (FIG. 10) showing a portion B in FIG. 7, the light emitting element 22 includes an element body 220 and an element housing 221 that houses the element body 220. The light emitting elements 22 are mounted by forming an annular element array at a predetermined interval so that the main emission direction is directed to the vertical (Z) direction with respect to the upper surface of the substrate body 21. On the mounting substrate 20, for example, a total of 18 light emitting elements 22 are face-up mounted on a wiring pattern using a COB (Chip on Board) technique. The diameter of the element row is about 90 mm.

The upper surface of the substrate body 21 is a reflecting surface for efficiently reflecting the emitted light of the light emitting element 22 toward the light guide plate 40 side.
The wiring 23 is used to supply power to the light emitting element 22 from the power supply unit 4 side. Both ends of the wiring 23 are electrically connected to the wiring pattern of the substrate body 21 and the power supply unit 4.

(Reflection member 30)
The reflection member 30 is a disk-shaped plate member disposed for the purpose of efficiently reflecting the light emitted from the light emitting element 22 and the light leaking from the light guide plate 40 toward the light guide plate 40 side. In the lighting fixture 1, the reflecting member 30 is sandwiched between the mounting substrate 20 and the light guide plate 40. The reflection member 30 is made of a material having high reflection characteristics, for example, any one of a high light reflection polybutylene terephthalate (PBT) resin, a high reflection polycarbonate (PC) resin, a high light reflection nylon resin, a high light reflection foamed resin, and the like. Composed. By reflecting and molding the reflecting member 30 using these resin materials, the reflecting member 30 can be configured with high accuracy. The reflection member 30 should just have a reflection characteristic in the surface at least.

  Fig.8 (a) is a top view of the reflection member 30 of the lighting fixture 1 which concerns on embodiment, (b) is sectional drawing cut | disconnected by the cross section AA in (a), (c) is a back view. . As shown in FIG. 8, the reflecting member 30 includes an inner reflecting portion 31, a recessed portion 32, and an outer reflecting portion 33 from the center side toward the outer side. The outer diameter of the reflecting member 30 is substantially matched with the inner diameter of the side wall portion 14. The inner reflection part 31 and the outer reflection part 33 have upper surfaces 310 and 330, respectively (FIG. 8B).

The inner reflection part 31 (outer reflection part 33) is provided at a position inside (outside) the mounting position of the light emitting element 22 of the mounting substrate 20 (FIG. 7). The inner reflection part 31 (outer reflection part 33) is a part for reflecting light leaking from the light guide plate 40 to the light guide plate 40 side again on the upper surface 310 (320).
The recessed portion 32 is provided in a region corresponding to a position directly above the mounting position of each light emitting element 22 on the mounting substrate 20. When the reflecting member 30 is viewed in plan, the recessed portion 32 is formed by recessed a circumferential region having a constant radius on the upper surface of the reflecting member 30 (the surface facing the light guide plate 40) in the thickness (Z) direction (FIG. 8). (B)).

As shown in FIGS. 7, 8 </ b> A, 8 </ b> B, 10 </ b> C, and FIG. 10, a plurality of penetrating members in the thickness direction of the reflecting member 30 are provided along the circumferential direction. Are present at regular intervals. The opening 34 exists immediately above the mounting position of the light emitting element 22 on the mounting substrate 20. In the opening 34, there are a pair of side walls 342 and 343 that reflect the emitted light of the light emitting element 22 on both sides of the opening 34 along the Y direction. As shown in FIG. 10, the side walls 342 and 343 form the periphery of the opening 34 along the Y direction, and are close to each other with an opening width W ₃₄ . The opening width W ₃₄ is substantially equal to the width W ₂₂ of the light emitting element 22, but the width W ₂₂ is configured to be smaller than the opening width W ₃₄ to such an extent that the light emitting element 22 is loosely inserted into the opening 34.

The reflecting member 30 has a concave portion 36 into which a convex portion 46 of a light guide plate described later is loosely inserted in the center of the upper surface 310. The position of the light guide plate 40 relative to the reflecting member 30 is restricted by loosely inserting a later-described convex portion 46 of the light guide plate 40 into the recess 36.
Further, a boss 37 having a screw hole 38 to be fastened to the base 10 with a screw 70 is formed on the back surface oriented to the upper surface 310 of the reflecting member 30. When the screw 70 inserted through the hole 17 of the base 10 is screwed into the screw hole 38 in the boss 37 of the reflecting member 30, the reflecting member 30 is fixed to the base 10.

As shown in FIG. 8B, the back surface 35 facing away from the recessed portion 32 and the outer reflecting portion 33 is a flat surface that matches the surface shape of the substrate body 21 of the mounting substrate 20.
(Light guide plate 40)
[overall structure]
The light guide plate 40 is used to guide light emitted from the light emitting element 22 mainly in the XY plane direction, and to emit light to the light collecting cover 60 side and the diffusion cover 50 (Z direction) side.

  Fig.9 (a) is a perspective view which shows the structure of the light-guide plate 40 of the illuminating device 100 which concerns on embodiment. (B) is the E section enlarged view in (a). As shown in FIGS. 7 and 9, the light guide plate 40 is disposed on the opposite side of the reflective member 30 from the side facing the mounting substrate 20. Examples of the material of the light guide plate 40 include materials having excellent translucency, such as acrylic resin, polycarbonate resin, polystyrene resin, and glass. In this embodiment, a polymethyl methacrylate resin is used as the acrylic resin. By injection-molding the light guide plate 40 using these materials, the light guide plate 40 can be configured with high accuracy in the same manner as the reflecting member 30.

The light guide plate 40 has a circular plate shape, and an annular portion 42 formed in an annular shape along the element row composed of the light emitting elements 22, and a circle formed continuously with the annular portion 42 inside the annular portion 42. A plate-shaped ring interior 41 is provided. Further, an annular annular outer peripheral portion 43 formed continuously with the annular portion 42 is provided outside the annular portion 42. 7 and 10, the range indicated by reference sign W ₄₂ is the annular portion 42, the range indicated by reference sign W ₄₁ is the ring interior 41, and the range indicated by reference sign W ₄₃ is the annular outer peripheral portion 43. In the present embodiment, the outer diameter of the light guide plate 40 including W ₄₁ to W ₄₃ is about 128 mm, and the diameter of the ring inner portion 41 is about 80 mm.

The outer diameter of the light guide plate 40 is substantially matched with the inner diameter of the side wall portion 14. A convex portion 46 is provided at the center of the surface of the inner ring 41 on the reflecting member 30 side. By loosely inserting the light guide plate 40 into the concave portion 36 of the reflection member 30, the positional relationship between the reflection member 30 and the light guide plate 40 can make the positional deviation error negligible.
In addition, the light guide plate 40 has a plurality of concave portions 47 for loosely inserting convex portions 62 of the light collecting cover 60 to be described later, slightly inside the outer edge of the ring interior 41 on the surface on the light collecting cover 60 side (FIG. 6). ). In the present embodiment, for example, the recesses 47 are provided at three positions with different circumferential angles by about 120 ° with respect to the center of the disc-shaped light guide plate 40. And this recessed part 47 is arrange | positioned in the position which overlaps with the center of the lens part 61 mentioned later in the Z direction in the state which accumulated the light guide plate 40 and the condensing cover 60, and overlapped.

Moreover, in the light guide plate 40, as an example, the outer surfaces of the ring interior 41 are set higher than the outer surfaces of the annular outer peripheral portion 43 (FIG. 7). Further, the thicknesses of the ring inner portion 41 and the annular outer peripheral portion 43 are also set to be the same.
[Annular part 42]
The annular portion 42 is a portion that receives the light emitted from the light emitting element 22 and guides it to the inside and outside of the light guide plate 40. In the luminaire 1, the annular portion 42 is inserted into the recessed portion 32 of the reflecting member 30 (FIG. 7). Thereby, the annular portion 42 is continuously formed so as to connect the mounting positions of the light emitting elements 22 on the mounting substrate 20.

  10A is an enlarged cross-sectional view showing a portion B in FIG. 7, and FIG. 10B is an enlarged cross-sectional view showing an F portion in FIG. As a specific configuration, as shown in FIG. 10, the annular portion 42 includes an element facing portion 420, an outer reflecting portion 422A, an inner reflecting portion 422B, and a boundary portion existing between the outer reflecting portion 422A and the inner reflecting portion 422B. 423. As shown in FIGS. 7 and 10, the annular portion 42 has a substantially V-shaped cross-sectional shape having a constant thickness as shown in FIGS. 7 and 10. On both sides of the annular portion 42 along the Y direction, an outer side surface portion 424A and an inner side surface having inclined surfaces similar to the outer reflection portion 422A and the inner reflection portion 422B on the opposite side to the outer reflection portion 422A and the inner reflection portion 422B. The part 424B exists (FIG. 10).

The element facing portion 420 is a portion that is disposed close to the light emitting element 22 and is disposed to face the emitting surface of the light emitting element 22 and constitutes a light introducing portion. Here, the surface shape of the element facing portion 420 facing the light emitting element 22 is a flat surface as an example (FIG. 9B). Therefore, the element facing portion 420 has end portions (light incident end portions 420A and 420B) located on both sides of the width W ₄₂₀ along the Y direction (FIG. 10). Here, the width W ₄₂₀ of the element facing portion 420 is substantially the same as the opening width W ₃₄ of the opening 34 in the reflecting member 30. The positional relationship is set so that the element facing portion 420 of the light guide plate 40 and the opening width W ₃₄ between the side walls 342 and 343 of the reflecting member 30 face each other. This is set so that the amount of light emitted from the light emitting element 22 is guided to the light guide plate 40 in the opening 34 without diverging.

  The outer reflection portion 422A and the inner reflection portion 422B are disposed on the surface of the light guide plate 40 opposite to the surface on which the element facing portion 420 is formed (upper surface in FIG. 10). Specifically, the outer reflecting portion 422A and the inner reflecting portion 422B have inclined surfaces in which the inclination angle smoothly increases with increasing distance from the element facing portion 420 in the vertical (Z) direction. Further, the outer reflecting portion 422A and the inner reflecting portion 422B have substantially line-symmetric shapes with respect to the vertical (Z) direction. The outer reflecting portion 422A and the inner reflecting portion 422B have the inclined surfaces as described above, so that the incident light incident along the (Z) direction directly above the element facing portion 420 is regularly reflected on the surface thereof, and the inside of the light guide plate 40 Can be guided efficiently.

The boundary part 423 has a protruding shape between the outer reflection part 422A and the inner reflection part 422B, and the size of the boundary part 423 is made as small as possible. Thus, the light emitted from the light emitting element 22 is adjusted so that it is difficult for the light emitted from the light emitting element 22 to penetrate the boundary portion 423 and become direct light when the lighting device 100 is driven.
The boundary portion 423 is located above the point 420C in the Z direction, which is divided approximately 1: 9 from the light incident end portion 420A side on the line segment connecting the light incident end portion 420A and the light incident end portion 420B. Therefore, in the X direction, the boundary portion 423 is located to the left by δ from the center of the light emitting element 22. This δ is preferably in the range of 0.6 to 0.7 times the width W ₂₂ of the light emitting element 22. As a result, light incident from the element facing portion 420 is guided to the outer reflecting portion 422A and the inner reflecting portion 422B at a ratio of approximately 1: 9, respectively, and is approximately 1: 9, respectively. 41 is adjusted so that the light is guided to 41.

The outer reflection portion 422A and the inner reflection portion 422B, the outer side surface portion 424A and the inner side surface portion 424B of the annular portion 42 are subjected to light reflection processing. Since the light scattering process is performed, the light incident on the element facing portion 420 is totally reflected and guided to the annular outer peripheral portion 43 and the annular inner portion 41.
[Inside ring 41]
The ring interior 41 is a part that guides the light of the light emitting element 22 that has entered the light guide plate 40 from the annular portion 42 to the inside of the mounting position of the light emitting element 22 and reflects it in the Z direction. A ring-shaped in-ring light guide.

The exit surface 410 facing the Z direction side of the ring interior 41 is subjected to a reflection process so that the light guided in the ring interior 41 is totally reflected. In addition, a light emitting surface from which a part of the light incident into the ring interior 41 at a certain angle or more is emitted.
The back surface 411 on the back side of the exit surface 410 of the ring interior 41 is also subjected to a reflection process so that the light guided in the ring interior 41 is totally reflected. In addition, in order to reflect the light guided into the inside 41 of the ring toward the emission surface 410 side, a plurality of concave reflecting portions 44 formed by recessing a part of the back surface 411 are provided. Therefore, the light incident on the inside 41 of the ring from the annular portion 42 is guided in the inside 41 of the ring, reflected on the exit surface 410 side by the concave reflection portion 44, and emitted from the exit surface 410 in the Z direction.

As shown in FIG. 7, the concave reflection portions 44 are arranged on the back surface 411 of the ring interior 41 so that the number per unit area is substantially uniform at an equal pitch. The light is emitted to. In the present embodiment, the concave reflecting portions 44 have a pitch in the radial direction of about 3 mm and are arranged in 26 rows over the range W ₄₁ in the inside 41 of the ring. The total number of concave reflecting portions 44 in the ring interior 41 is 491. Details of the shape of the concave reflection portion 44 will be described later.

[Annular outer periphery 43]
The annular outer peripheral portion 43 is a portion that guides the light of the light emitting element 22 that has entered the light guide plate 40 from the annular portion 42 to the outside of the mounting position of the light emitting element 22 and reflects it in the Z direction. A light guide is formed. The outer peripheral edge portion of the annular outer peripheral portion 43 is sandwiched between the main body portion 11 and the side wall portion 52 of the diffusion cover 50 while being placed on the main body portion 11 of the base 10.

The surface on the Z direction side of the annular outer peripheral portion 43 is an emission surface 430, and is subjected to a reflection process so that light guided in the annular outer peripheral portion 43 is totally reflected. In addition, a light exit surface from which a part of the light incident into the annular outer peripheral portion 43 at a certain angle or more is emitted.
The surface 431 on the back side of the emission surface 430 of the annular outer peripheral portion 43 is also subjected to a reflection process so that the light guided through the annular outer peripheral portion 43 is totally reflected. In addition, in order to reflect the light guided into the annular outer peripheral portion 43 to the emission surface 430 side, a plurality of concave reflection portions 45 formed by recessing a part of the surface 431 are provided. Therefore, the light that has entered the annular outer peripheral portion 43 from the annular portion 42 is guided through the annular outer peripheral portion 43, reflected by the concave reflecting portion 45 toward the emission surface 430, and emitted from the emission surface 430 in the Z direction.

As shown in FIG. 7, the concave reflecting portions 45 are arranged on the surface 431 of the annular outer peripheral portion 43 so that the number per unit area is substantially uniform at an equal pitch. Light is emitted uniformly. In the present embodiment, the concave reflecting portions 44 have a pitch in the radial direction of about 1.7 mm, and are arranged in eight rows on one side (16 rows on the left and right sides) in the range W ₄₃ of the annular outer peripheral portion 43. The total number of concave reflecting portions 45 in the annular outer peripheral portion 43 is 1571. The shape of the concave reflecting portion 45 is the same as the shape of the concave reflecting portion 44 described later.
[Concave reflector 44]
FIG. 11 is an enlarged cross-sectional view showing a portion C in FIG. As shown in FIG. 11, a plurality of concave reflecting portions 44 are provided on the back surface of the light guide plate 40 by recessing a part of the back surface 411. The concave reflecting portion 44 is a conical concave portion with the top portion facing the emission surface 410 side. Therefore, the portion that hits the bottom surface of the cone is an opening that opens on the back surface 411. Here, in the XY plane direction, it is necessary that each of the plurality of concave reflecting portions 44 and the lens unit 61 are individually arranged in an optically facing relationship when the XY direction is viewed in plan. . “Arranged while maintaining the optical facing relationship” means that the light reflected by the concave reflecting portion 44 and incident on the lens portion 61 is condensed as illumination light, and further has the following relationship: It points to something. In other words, the center position 44 </ b> A of the concave reflecting portion 44 is arranged so as to be closer to the center of the light guide plate 40 than the central axis 61 </ b> A of the lens portion 61 in the concave reflecting portion 44 and the lens portion 61 that are opposed to each other. In addition, the closer to the peripheral edge of the light guide plate 40, the larger the amount of deviation is than the one existing at the center of the light guide plate. The same number of concave reflection portions 44 as the lens portions 61 of the light collecting cover 60 are provided.

The positional relationship between the concave reflection portion 44 and the lens portion 61 can be changed without being limited to the above embodiment as long as the reflected light from the concave reflection portion 44 can be condensed in the main emission direction perpendicular to the main surface. .
FIG. 12 is a schematic diagram illustrating a cross-sectional shape of the concave reflecting portion 44 in the light guide plate 40 of the lighting fixture 1. The plate thickness t ₁ of the light guide plate 40 is about 1.5 mm in the present embodiment. The concave reflecting portion 44 is a conical concave portion having a cone angle θ, a height h, and a central axis 44A. The conical portion is a space whose bottom surface is an opening. θ was 76 ° ± 1 °, h was 0.4 to 0.7 mm, and r at the tip was about 0.1 mm. However, the above is an example, and the shape of the concave reflection portion 44 is not limited to the above. For example, the cone angle of the concave reflecting portion 44 can be adjusted in consideration of the refractive index of the material of the light guide plate 40.

In addition, the light reflection part given to the ring inside 41 and the ring outer peripheral part 43 is not limited to the above, but can be changed as described later in a modification.
(Condensing cover 60)
[overall structure]
The condensing cover 60 is used to allow light emitted from the light guide plate 40 to be incident, emitted in the Z direction, and condensed. The condensing cover 60 is configured using a translucent material such as a silicone resin, an acrylic resin, a polycarbonate resin, or glass. In this embodiment, a polymethyl methacrylate resin is used as the acrylic resin.

13A is a plan view of the light collection cover 60 of the luminaire 1, FIG. 13B is an enlarged view of the G part in FIG. 13A, FIG. 13C is a side view, and FIG. . As shown in FIGS. 7 and 13, the light collection cover 60 has a disk shape centered on a point 600 </ b> A, and has a lens region 63 covering the emission surface 410 of the inner ring 41 of the light guide plate 40 and an outer periphery of the lens region. And a peripheral edge 64 positioned. In FIG. 7 and FIG. 13, the range indicated by reference sign W ₆₃ is the lens region 63, and the range indicated by reference sign W ₆₄ is the peripheral edge portion 64. In the present embodiment, the lens region 63 is about 80 mm. The center 600A of the light collecting cover 60 is at the same position as the center 0 (FIG. 5) of the lighting fixture 1 in the XY plane.

The light collecting cover 60 is disposed between the light guide plate 40 and the diffusion cover 50 in a state where the back surface 65 is brought into contact with the emission surface 410 of the light guide plate 40 and the peripheral edge portion 64 is in contact with the back surface 511 of the diffusion cover 50 described later. Is sandwiched between. At this time, the lens region 63 of the light collecting cover 60 is fitted to the opening 53 of the diffusion cover 50, and the lens region 63 is exposed from the opening 53 (FIG. 7).
The condensing cover 60 has a plurality of convex portions 62 that are loosely inserted into the concave portions 47 of the light guide plate described above inward of the peripheral edge portion 64 on the back surface 65. The position of the light guide plate 40 relative to the reflecting member 30 is restricted by loosely inserting a later-described convex portion 46 of the light guide plate 40 into the recess 36. In the present embodiment, for example, the convex portion 62 is provided at three locations with different circumferential angles by about 120 ° with respect to the center 600A of the lens region 63. In addition, the convex part 62 is each arrange | positioned in the center of the lens part 61 mentioned later. This is because, in terms of orientation characteristics, the center of the lens portion 61 is a position where the unevenness in illuminance due to the convex portion 62 is least noticeable.

[Lens 61]
The arrangement of the lens unit 61 in the planar direction will be described. As shown in FIG. 13A, the lens region 63 of the light collecting cover 60 has a plurality of lens portions 61. As shown in FIG. 13B, the lens unit 61 is positioned so that the center of the lens unit 61 is concentrically arranged with a pitch p between the circumferences of the lens region 63 as a reference with the center 600A of the lens region 63 as a reference. Be placed. In addition, on each circumference, a number of lens parts 61 whose arc distance between the centers of adjacent lens parts 61 is closest to the pitch p are arranged. In the present embodiment, a configuration is adopted in which six lens portions 61 are arranged on the circumference of the first row from the center 600A, and thirteen lens portions 61 are arranged on the circumference of the second row. The total number of lens units 61 is 491.

Next, the cross-sectional shape of the lens unit 61 will be described. FIG. 14 is a schematic diagram illustrating a cross section of the lens portion 61 in the light collection cover 60 and the concave reflection portion 44 in the light guide plate 40 of the illumination device 100. The plate thickness t ₁ of the light guide plate 40 is about 1.5 mm as described above, and the maximum thickness of the light collecting cover 60 is 2.5 mm. As shown in FIG. 12, the light guide plate 40 and the light collection cover 60 each have a portion in contact with each other in the optical path from the concave reflection portion 44 to the lens portion 61. As shown in FIG. 14, the lens unit 61 has an aspherical shape centered on an intersection 610 </ b> B between a central axis 61 </ b> A passing through the vertex 610 </ b> A of the lens surface 610 and parallel to the Z axis and the back surface 411 of the light guide plate 40. 610. The radius r of the lens surface 610 is defined by the following equation as a function of the angle θ with respect to the central axis 44A, where t _{2 is} the distance from the back surface 411 of the light guide plate 40 to the vertex 610A of the lens surface 610, and n is the refractive index. Is done.

r = (n−1) × t ₂ / (n−cos θ)
In this embodiment, t ₂ is 4.0 mm and n is 1.491.
(Position misalignment between the lens portion 61 and the concave reflection portion 44 (offset))
In the illuminating device 10, at the center of the light guide plate 40 and the light collecting cover 60, the concave reflecting portion 44 is positioned so that the center line of the cone coincides with the center line of the lens portion 60 provided on the light collecting cover 60. Has been placed. On the other hand, at a position excluding the centers of the light guide plate 40 and the light collecting cover 60, as shown in FIG. 14, the center axis 61A of the lens portion 61 and the center axis 44A of the cone of the concave reflection portion 44 are distances in the X direction. The positions are shifted by d.

FIG. 15 is an explanatory diagram showing the arrangement in the XY direction of the concave reflecting portion 44 of the light guide plate 40 of the lighting fixture 1 superimposed with the arrangement in the XY direction of the lens portion 61 of the light collecting cover 60. As shown in FIG. 15, in the lens unit 61, as described above, the central axis 61A of the lens unit 61 is positioned in a concentric circle with the radial pitch P ₆₁ as a reference with the center 600A of the lens region 63 as a reference. To be arranged. In contrast, the concave reflecting section 44 is also relative to the center 600A, arranged pitch of the radial so that the central axis 44A of the cone concave reflecting portion 44 to the circumferential concentric circles P ₄₄ is positioned .

In the radial direction with reference to the center 600A, the central axis 44A of the concave reflecting portion 44 is located on a straight line connecting the center 61A of the lens portion 61 and the center 600A that are closest to each other.
In the present embodiment, a configuration is adopted in which six concave reflecting portions 44 are arranged on the circumference of the first row from the center 600A, and thirteen concave reflecting portions 44 are arranged on the circumference of the second row. . Further, the total number of concave reflecting portions 44 in the ring interior 41 is 491 as in the lens portion 61.

FIG. 16 is an enlarged cross-sectional view showing a portion D in FIG.
As shown in FIG. 16, at the center 600 </ b> A of the light collection cover 60, the center axis 61 </ b> A of the lens portion 61 is located at the same center 600 </ b> A as the center axis 44 </ b> A of the concave reflection portion 44.
Then, P ₄₄ in the radial direction of the pitch of the concave reflecting portion 44 is constant regardless of the distance from the center 600A. Also, P ₆₁ in the radial direction of the pitch of the lens unit 61 is constant regardless of the distance from the center 600A. Then, P ₄₄ the pitch of the concave reflecting portion 44 is set smaller than P ₆₁ the pitch of the lens portion 61. In the present embodiment, as an example, the pitch of the lens portions ₆₁ is set to 3.05 mm for P ₆₁ , and the pitch of the concave reflection portions ₄₄ is set to 3.022 mm to 3.034 mm for P ₄₄ . However, the value of each pitch is not limited to the above, and can be selected as appropriate. Thereby, the central axis 61 </ b> A of the lens part 61 is located on the outer side in the radial direction with respect to the central axis 44 </ b> A of the concave reflecting part 44. In the first column on the circumference from the center 600A of concentric circles centered 600A canceled, the central axis 61A of the length lens portion 61 a pitch corresponding to P ₆₁ and pitch difference d between P ₄₄ is concave reflection The portion 44 is located on the outer side in the radial direction with respect to the central axis 44A. The distance between both centers in the radial direction is defined as a shift amount (offset amount) d ₁ .

Similarly, in the second column on the circumference from the center 600A, the central axis 61A of the length lens unit 61 corresponding P ₆₁ and the pitch on the pitch twice the difference d between P ₄₄ is concave reflecting portion 44 It is located outside of the central axis 44A in the radial direction. The amount of deviation d ₂ the distance in the radial direction of the center of both.
Further, the third row from the center 600A in the circumference, the center axis 61A of the length lens unit 61, which corresponds to the pitch of P ₆₁ and the pitch to three times the difference d between P ₄₄ is the concave reflecting section 44 It is located outside of the central axis 44A in the radial direction. A distance in the radial direction between both the centers is defined as a shift amount d ₃ .

Thus, the shift amount d _n is 0 at the center 600A of the light collecting cover 60, is determined based on the distance from the center 600A to the lens unit 61, and increases from the center 600A toward the peripheral portion 64 of the lens region 63. doing.
As described above, in the present embodiment, the center position 44A of the concave reflecting portion 44 existing from the vicinity of the center O of the ring interior 41 to the peripheral edge is the center position 61A of the lens portion 61 that has an optical facing relationship. Rather, the position is shifted so as to approach the radial center O of the inside 41 of the ring. Further, the position of the concave reflection portion 44 near the periphery of the ring interior 41 has a larger amount of deviation than the position of the concave reflection portion 44 near the center inside the ring. In addition, the amount of deviation is gradually increased from the center O of the annular portion 41 toward the periphery.

(Diffusion cover 50)
The diffusion cover 50 is disposed for the purpose of obtaining surface light emission with a uniform luminance distribution by further scattering the light emitted from the annular outer peripheral portion 43 of the light guide plate 40. The diffusion cover 50 is configured using a light transmissive material such as silicone resin, acrylic resin, polycarbonate resin, or glass.

As shown in FIGS. 7 and 13, the condensing cover 60 has an annular shape having an annular portion 51 in which an opening 53 for exposing the lens region 63 of the condensing cover 60 is formed in the central portion. The lighting device 100 is assembled by having the side wall 52 on the periphery of the annular portion 51 and fitting the side wall 52 to the flange 12 of the base 10. In the assembled state, the surface 510 of the annular portion 51 constitutes the appearance of the lighting fixture 1. At this time, the back surface 511 of the diffusion cover 50 abuts the peripheral edge portion 64 of the light collecting cover 60 and presses the light collecting cover 60 against the light guide plate 40. In addition, the ribs 54 erected on the back surface 511 are in contact with the emission surface 430 of the annular outer peripheral portion 43 of the light guide plate 40 and press the light guide plate 40 against the base 10. The side wall portion 52 of the diffusion cover 50 and the flange portion 12 of the base 10 are fixed by a resin spring or the like (not shown). In FIG. 7, the range indicated by the symbol W ₅₃ is the opening 53, and in this embodiment, is about 80 mm.

The annular portion 51 is subjected to a light scattering process, and is adjusted so as to efficiently scatter light emitted from the annular outer peripheral portion 43 of the light guide plate 40. As the light scattering treatment, for example, the surface of the annular portion 51 facing the light guide plate 40 may be finely processed.
<Operation of Lighting Device 100>
When the user uses the lighting device 100 having the above configuration, the lighting device 100 is powered on. In the lighting device 100, power is supplied to each light emitting element 22 from the power supply unit 4 connected to a commercial power supply via the wiring 23. Thereby, outgoing light is generated from each light emitting element 22.

  Light emitted from the light emitting element 22 enters the annular portion 42 of the light guide plate 40 from the element facing portion 420 through the opening 34 of the reflecting member 30. Incident light repeats regular reflection inside the light guide plate 40 and diffuses inside both the ring interior 41 and the annular outer periphery 43. Further, the light leaking downward from the light guide plate 40 is reflected on the upper surfaces 310 and 330 (FIG. 8) of the reflection member 30 and is incident on the light guide plate 40 side again.

The emitted light of the light emitting element 22 reflected in the direction of the emission surface 410 by the concave reflecting portion 44 formed on the back surface 411 of the light guide plate 40 is emitted from the emission surface side of the light guide plate 40 and is incident on the light collecting cover 60. The Incident light is condensed on the target surface in the main emission direction as illumination light by the lens portion 61 of the light collecting cover 60.
On the other hand, the emitted light of the light emitting element 22 reflected in the direction of the emitting surface 430 by the concave reflecting portion 45 formed on the back surface 431 of the light guide plate 40 is emitted from the upper surface side of the light guide plate 40 and enters the diffusion cover 50. . Incident light is further diffused by the annular portion 51 of the diffusion cover 50 that has been subjected to light scattering treatment, and is finally emitted to the outside as illumination light.

As described above, the illumination device 100 according to the present embodiment passes the inner peripheral side of the annular diffused light irradiated from the diffusion cover 50 and the disc-shaped spot light from the light collecting cover 60 on the target surface. Irradiated towards.
<Effects produced by lighting device 100>
When the illumination device 100 is driven, the following effects can be expected.

(Effects regarding thickness reduction of lighting device 100)
In the conventional lighting device 800 shown in FIG. 27, for example, when the ½ beam angle is set within ± 45 ° as described above in the illuminance distribution, the diameter of the Fresnel lens 803 is set assuming that the diameter of the phosphor layer 8022 is 60 mm. Is 162 mm. At this time, 27 mm must be secured as an optical path (distance Y ₀ ) between the light emitting element 8021 and the Fresnel lens 803. Accordingly, it is difficult to reduce the thickness of the lighting device 800.

On the other hand, in the illuminating device 100, parallel light can be incident on the upper lens portion 61 located in the (Z) direction directly above each concave reflection portion 44 from a shorter distance than each concave reflection portion 44. Therefore, the optical path between the light emitting element 22 and the light collecting cover 50 in the thickness (Z) direction of the lighting fixture 1 can be made relatively short. Thus it is possible to suppress the thickness Y ₁ of the luminaire 1 to less than about 18 mm, it is possible to achieve a good thickness of the lighting device 100.

(Effects on orientation characteristics)
[Specific effects]
FIGS. 17A and 17B are explanatory views of the light collecting principle of the light guide plate 40 and the light collecting cover 60 in the lighting device 100, where FIG. 17A shows the vicinity of the central portion of the light collecting cover 60, FIG. Is the right edge periphery, and (d) is the total sum. As shown in FIG. 17A, the emitted light of the light emitting element 22 is reflected in the direction of the emitting surface 410 by the concave reflecting portion 44 formed on the back surface 411 of the light guide plate 40. At that time, the reflecting surface of the concave reflecting portion 44 is at a position shifted from the central axis 44A, and light reflected from the reflecting surface, for example, light of s1, s2, s3, s4 or t1, t2, t3, t4 is condensed. After entering the cover 960, the lens unit 961 converts the light into a light inclined with respect to the front in the main emission direction. For this reason, the peak of the intensity of the light emitted from the circularly-shaped concave reflector 44 is formed at a position slightly deviated from the orientation angle of 0 °. For example, when the diameter of the bottom surface of the cone in the concave reflecting portion 944 is 0.8, the intensity peak of the emitted light occurs at an angle of about ± 5 °.

Here, in the vicinity of the central portion of the light collecting cover 60, the distance from the light emitting element 922 is substantially equal on the left and right, and the light incident on the concave reflecting portion 44 is substantially equal on the left and right. Therefore, two equal illuminance peaks are formed on the target surface. The peak-to-peak distance X ₀ is, for example, several tens of centimeters on the symmetry plane located at a distance Z ₂₀₀₀ of about 2 m.
Next, FIG. 17B illustrates the left end peripheral portion of the light collecting cover 60. In the vicinity of the left end, the distance from the light emitting element 22 is different on the left and right in the vicinity of the left end of the light collecting cover 60, the distance from the left light emitting element 22 is short, and the distance from the right light emitting element 22 is large. Therefore, the light entering the concave reflecting portion 44 from the left side has a larger luminous flux than the light entering from the right side. In the illuminating device 100, the central axis 61 </ b> A of the lens unit 61 is arranged to be shifted to the left by a distance d with respect to the central axis 44 </ b> A of the concave reflection unit 44 at the left end peripheral portion of the light collecting cover 60. take. Therefore, although the reflecting surface of the concave reflecting portion 44 is located at a position shifted to the left from the central axis 44A, it is located immediately below the central axis 61A of the lens portion 61 or shifted to the right by a minute distance. Therefore, light that enters and is reflected from the left side into the concave reflecting portion 44, for example, light of u1, u2, u3, and u4, is incident on the light collecting cover 60 and then converted into light perpendicular to the front in the main emission direction by the lens portion 61. Converted. Therefore, the light reflected by the concave reflecting portion 44 of the light guide plate 40 located around the left end portion of the light collecting cover 60 is condensed at an angle θ ₁ of 5 ° or less, and only on the target surface at the angle θ ₁ . Illuminance peaks are formed.

Next, FIG. 17C shows the right end peripheral portion of the light collecting cover 60. In the right end peripheral portion, the distance from the light emitting element 22 is different on the left and right sides around the right end portion of the light collecting cover 60, the distance from the right light emitting element 22 is short, and the distance from the left light emitting element 22 is large. Therefore, the light entering the concave reflecting portion 44 from the right side has a larger luminous flux than the light entering from the left side. In the illuminating device 100, the central axis 61 </ b> A of the lens unit 61 is arranged to be shifted to the right by the distance d with respect to the central axis 44 </ b> A of the concave reflection unit 44 in the right end peripheral part of the light collecting cover 60. take. Therefore, although the reflecting surface of the concave reflecting portion 44 is located at a position shifted to the right from the central axis 44A, it is located directly below the central axis 61A of the lens portion 61 or shifted to the left by a minute distance. Therefore, light that enters and is reflected from the right side into the concave reflecting portion 44, for example, light of v1, v2, v3, and v4, is incident on the light collecting cover 60 and then converted into light perpendicular to the front in the main emission direction by the lens portion 61. Converted. Therefore, the light reflected by the concave reflecting portion 44 of the light guide plate 40 located around the right end portion of the condensing cover 60, 5 ° is condensed into the following angle - [theta] _1, the on target surface angle - [theta] ₁ Only the peak of illuminance is formed.

Then, when the illuminance distribution shown in FIGS. 17A to 17C is superimposed, the illuminance distribution having an illuminance peak at an angle of 0 ° on the target surface as shown in FIG. Is formed.
[Performance confirmation result 1]
The change of the orientation characteristic for each position in the lens region 63 of the light collecting cover 60 in the illumination device 100 was calculated by optical simulation. FIG. 18 is a schematic diagram showing a masking pattern 700 used for calculation of orientation characteristics for each position in the lens region 63 of the illumination device 100. The masking pattern 700 has a disk-shaped mask region 720 having a diameter of 80 mm and an opening 710 having a diameter of 20 mm centered at a position r away from the center. Assuming that the mask region 720 is aligned with the lens region 63 of the light collecting cover 60, the orientation characteristics of the illumination light irradiated from the opening portion in the illumination device 100 were obtained by optical simulation.

FIG. 19 is a characteristic diagram showing the calculation result of the orientation characteristic of the illumination device 100. 19A shows illumination light from the φ20 mm range from the center of the ring interior 41 of the light guide plate 40, and FIG. 19B shows illumination light from a φ20 mm range centered at a position 10 mm away from the center of the ring inside 41 ( c) shows the illumination light from the φ20 mm range centered at a position 20 mm away, and (d) shows the orientation characteristics of the illumination light from the φ20 mm range centered at a position 30 mm away. P ₆₁ the pitch of the lens unit 61 is 3.05 mm, P ₄₄ the pitch of the concave reflecting portion 44, and a 3.024Mm. Each characteristic diagram shows an alignment characteristic in the X direction in FIG.

  In the illumination light from the φ20 mm range from the center shown in FIG. 19A, there is an illuminance peak at the orientation angle ± 8 °, and there is a drop in illuminance near the orientation angle of 0 °. In the illumination light from the φ20 mm range centered at a position 10 mm away from the center shown in FIG. 19B, the two illuminance peaks and the illuminance drop between them move to the right, and the illuminance at the left peak is Increasing and the illuminance at the right peak decreases. In the illumination light from the φ20 mm range centering on a position 20 mm away from the center shown in FIG. 19 (c), the two peaks and the drop between them move further to the right, and the illuminance at the left peak further increases and the right side The illuminance at the peak is further reduced. In FIG. 19D, which shows the orientation characteristics from a φ20 mm range centered at a position 30 mm away from the center, the drop in illuminance near the orientation angle of 0 ° is eliminated, and the left side illuminance peak has an orientation angle of 0 °. The illuminance value at the peak on the right side is further reduced.

As described above, in the illumination light from the φ20 mm range centered at positions 10 mm, 20 mm, and 30 mm away from the center, the drop in illuminance moves to the right as the distance r from the center increases.
Next, with respect to the alignment characteristics of the light irradiated from the entire surface of the light collecting cover 60 in the illumination device 100, calculation by optical simulation was performed under the condition where the masking pattern 700 was removed. FIG. 20 is a characteristic diagram illustrating the alignment characteristics of light emitted from the entire surface of the light collecting cover 60 in the illumination device 100. As shown in FIG. 20, an illuminance distribution having a single peak at an orientation angle of 0 ° is obtained. In this way, the alignment characteristics of light emitted from different positions of the light collecting cover are made different so that the unevenness in each illuminance distribution is superimposed so as to be complemented with each other. As a result, the drop in illuminance near the orientation angle of 0 ° can be improved, and an illuminance distribution having a single peak at the orientation angle of 0 ° can be obtained.

[Performance confirmation result 2]
The pitch of the lens unit 61 in the lighting apparatus 100 P ₆₁ is set to 3.05 mm, the P ₄₄ the pitch of the concave reflecting portion 44, by changing from 3.034mm to 3.022Mm, for changes in orientation characteristics, by optical simulation Calculated. FIG. 21 shows a change in the alignment characteristics of light irradiated from the entire surface of the light collection cover 60 when the _P44 ratio is changed in the pitch of the concave reflection portion 44 with respect to the pitch P ₆₁ of the lens portion 61 in the illumination device 100. FIG. In parentheses in the figure, the pitch for the pitch P ₆₁ shows the proportion of P _44. The peak of illuminance at an orientation angle of 0 ° increases as the ratio of the pitch P _{44 to} the pitch P ₆₁ decreases from 99.48%, and becomes maximum when the ratio is 99.15%. In addition, at 99.24% or less and 99.08% or more, the illuminance distribution shows a continuous curve without unevenness.

[Performance confirmation result 3]
About the orientation characteristic of the illuminating device 100, the calculation by optical simulation was performed. FIG. 22 is a characteristic diagram showing the calculation result of the orientation characteristic of the illumination device 100. FIG. 22A shows the distribution of illuminance when the illumination device 100 is installed at the center O, the 0 ° direction is turned on as the main emission direction, and the target surface 2 m ahead of the light source is irradiated. FIG. 5 is a characteristic diagram showing the circumferential direction on the circumferential coordinate with the radial direction as illuminance. Further, (b) is a characteristic diagram shown in orthogonal coordinates.

P ₆₁ the pitch of the lens unit 61 in the lighting apparatus 100 is 1.8 mm, P ₄₄ the pitch of the concave reflecting portion 44, and 1.795Mm, the thickness t ₁ of the light guide plate 40 and 1.5 mm.
Similarly, as a comparative example, calculation was performed by optical simulation in the case where the pitch of the lens portion 61 is equivalent to P ₆₁ and the pitch of the concave reflection portion 44. FIG. 23 is a characteristic diagram showing calculation results of orientation characteristics of the comparative example of the illumination device 100. In the comparative example, the pitch of the lens portions 61 is P ₆₁ and the pitch of the concave reflection portions ₄₄ is 1.8 mm for P _{44 and} the thickness t ₁ of the light guide plate 40 is 1.5 mm. Other conditions are the same as those of the lighting device 100.

As shown in FIGS. 22A and 22B, in the illumination device 100, the ½ beam angle θ _1, which is one of the scales for evaluating the orientation, is 18 °. In the comparative example, the 1/2 beam angle θ ₂ was 25 °. Here, the 1/2 beam angle refers to the angle formed by the line connecting the point where the illuminance is ½ of the illuminance directly below the light source, the center of the light source, and the vertical direction line of the light source center, and the degree of light distribution. Show. In a concentrating illumination device using a conventional Fresnel lens, the 1/2 beam angle was 45 ° (Patent Document 1). On the other hand, in the illumination device 100, the 1/2 beam angle can be reduced to 18 °. In addition, as compared with the comparative example, the 1/2 beam angle which was 25 ° can be reduced to 18 ° as described above.

Further, as shown in FIGS. 22A and 22B, the illumination device 100 eliminates the drop in illuminance near the orientation angle of 0 ° in the comparative example shown in FIGS. 23A and 23B. can do.
Similarly, in the illumination device 100, the pitch of the pitch P ₆₁ and a concave reflecting portion 44 of the lens portion 61 P ₄₄ was subjected to calculation by optical simulation when expanded together. FIG. 24 is a characteristic diagram showing the calculation result of the orientation characteristic of the illumination device 100. FIG. P ₆₁ the pitch of the lens unit 61 in the lighting apparatus 100 is 3.05 mm, P ₄₄ the pitch of the concave reflecting portion 44 was 3.03 mm, the thickness t ₁ of the light guide plate 40 and 1.5 mm.

As shown in FIGS. 24A and 24B, in the illumination device 100, the 1/2 beam angle θ ₃ is 18 °, which is the same as θ ₁ .
Furthermore, in FIG. 24, it was confirmed that the peak of about illuminance 300 cd observed at the orientation angles ± 40 ° to 45 ° seen in FIGS. 22 and 23 was eliminated. The peak at the orientation angle of ± 40 ° to 45 ° is that the reflected light from the concave reflection portion 44 enters the lens portion 61 around the lens portion 61 that has an optically opposed relationship with the concave reflection portion 44 individually. It is thought that it occurs by. 24, the pitch P ₆₁ of the lens portion 61 and the pitch of the concave reflecting portion ₄₄ are both increased by P ₄₄ , and the ratio of P ₆₁ and P ₄₄ to the thickness t ₁ (1.5 mm) of the light guide plate 40 is about Increased to 2 or more. Thus, it is considered that the incident light to the surrounding lens unit 61 can be prevented, and the peak of illuminance of about 300 cd generated in the vicinity of the orientation angle of ± 40 ° to 45 ° can be eliminated. Further, the pitch in the radial direction of the concave reflecting portion 44 in the light guide plate 40 is 1.5 to 2.5 times, more preferably 2 to 2.5 times the thickness t _{1 of the} light guide plate. . As the thickness t ₁ of the light guide plate 40 increases, the radial pitch of the concave reflection portions 44 in the light guide plate 40 increases accordingly, so the area ratio of the concave reflection portions 44 in the light guide plate 40 per unit area decreases. The radiation intensity (total luminous flux) becomes small. Therefore, it is desirable to reduce the thickness t ₁ of the light guide plate 40 as much as possible after eliminating the illuminance peak occurring in the vicinity of the orientation angle of ± 40 ° to 45 °.

(Brief Summary)
As described above, the illumination device 100 has the above-described configuration, and in the concentrating illumination device, an orientation angle with a ½ illuminance angle of 18 ° is eliminated while eliminating a drop in illuminance near the orientation angle of 0 °. Was able to be realized. In addition, it was possible to eliminate the illuminance peak occurring in the vicinity of the orientation angle of ± 40 ° to 45 °. By adopting this method, it is possible to provide a lighting device that is thin and can realize narrow orientation.

≪Modification≫
The lighting device 100 according to the embodiment has been described above. However, the illustrated lighting device 100 can be modified as follows, and the present invention is applied to the lighting device 100 as described in the above embodiment. Of course, it is not limited.
In the illuminating device 100 according to the above-described embodiment, the concave reflecting portion 44 is configured to have a constant height h as shown in FIG. However, the height of the concave reflecting portion 44 may be different depending on the location of the lens region 63.

FIG. 25 is an enlarged cross-sectional view showing the same part as the portion D of FIG. 7 related to the illumination device 100 in the illumination device 100A according to the modification. In the illumination device 100 </ b> A, the height h of the concave reflection portion 44 increases from the center 600 </ b> A of the light collecting cover 60 toward the peripheral edge 64 of the lens region 63, and the height h is the distance from the center 600 </ b> A to the concave reflection portion 44. Based on this configuration. In other words, the height h of the concave reflection portion 44 is h ₀ <h ₁ <h _{2 as} shown in FIG. 25, where hi is the height of the concave reflection portion 44 on the circumference of the nth column from the center 600A. <H ₃ <h ₄ <h ₅ <h ₆ is satisfied. That is, the height of the concave reflection portion 44 is the lowest at the center of the light guide plate 40, gradually increases from the center to the vicinity of the periphery, and is highest at the vicinity of the periphery. About another structure, it is the same as that of the illuminating device 100, and abbreviate | omits description.
<Effects produced by lighting device 100A>
When the illumination device 100A is driven, the following effects can be expected.

(Orientation characteristics)
[Specific effects]
FIG. 26 is an explanatory diagram of the light collection principle of the light guide plate 40 and the light collection cover 60 in the illumination device 100A according to the modification, where (a) is near the central portion of the light collection cover 60 in the comparative example, and (b) is FIG. In the vicinity of the central portion in the modified example, (c) shows the state of the peripheral portion in the modified example.

  The size of the concave reflecting portion 44 affects the luminous flux of the reflected light, and the larger the concave reflecting portion 44 is, the larger the luminous flux of the reflected light is and the higher the efficiency of the illumination device. The size of the concave reflection portion 44 is represented by the height of the cone and the radius of the bottom surface of the conical concave reflection portion 44. However, as shown in FIG. 27A, in the vicinity of the central portion of the light collecting cover 60, when the size of the concave reflection portion 44 is large and the radius of the bottom surface is large, the reflected light enters the peripheral portion of the lens portion 61. The orientation angle increases. This is because the positional deviation amount δ of the reflecting surface of the concave reflecting portion 44 with respect to the central axis 61A of the lens portion 61 is large.

In the modified example, as shown in FIG. 27B, the radius of the bottom surface is reduced by reducing the size of the concave reflecting portion 44 near the central portion of the light collecting cover 60, and the lens of the reflecting surface of the concave reflecting portion 44 is reduced. The positional deviation amount δ of the portion 61 with respect to the central axis 61A is decreased. This prevented light from entering the peripheral part of the lens part 61 and prevented the orientation angle from expanding.
On the other hand, in the vicinity of the peripheral portion of the light collecting cover 60, the central axis 44A of the concave reflecting portion 44 is offset in the radial direction toward the central axis 61A of the lens portion 61 as described above. In the vicinity of the peripheral edge of the light collecting cover 60, the distance from the light source existing on the left side is short in FIG. 27C, and the intensity of the light beam from the arrow indicated by the solid line is greater than the intensity of the light beam indicated by the dotted line. Also gets higher. Therefore, even when the size of the concave reflection portion 44 is large and the radius of the bottom surface is large, the positional deviation amount δ of the reflection surface of the concave reflection portion 44 with respect to the central axis 61A of the lens portion 61 is small. Therefore, as shown in FIG. 27C, in the modified example, the size of the concave reflecting portion 44 is enlarged in the vicinity of the peripheral portion of the light collecting cover 60 as compared with the central portion. Thereby, in the vicinity of the peripheral portion of the light collecting cover 60, the size of the concave reflection portion 44 can be increased, and an increase in the orientation angle that prevents light from entering the peripheral portion of the lens portion 61 can be prevented.

As a result, the illumination device 100A according to the modification can improve the efficiency as the illumination device while realizing a narrow orientation equivalent to that of the illumination device 100 according to the embodiment.
≪Summary≫
As described above, the illumination device 100 according to the present embodiment includes the light emitting unit in which a plurality of light emitting elements are arranged in a ring shape on the substrate, the light introducing unit that faces the light emitting element array of the light emitting unit, and the introduction. A light guide plate having a disk-shaped in-ring light guide part for guiding the light in the ring inner direction, a disk-shaped light collecting cover disposed on one main surface side of the light guide plate,
The light guide plate has a plurality of concave reflectors recessed in the back surface facing away from the main surface in order to change the optical path of the guided light toward the main surface at a plurality of locations. The condensing cover is disposed in an optically opposing relationship with each of the plurality of concave reflecting portions and reflects light from each concave reflecting portion in a main emission direction perpendicular to the main surface. A plurality of condensing lens portions, and the individual optical facing relationship between the concave reflecting portion and the lens portion is such that the center position of the concave reflecting portion is the lens portion of the concave reflecting portion and the lens portion in the facing relationship. It is shifted so that it is closer to the center of the light guide in the ring than the center axis, and the amount of shift closer to the periphery of the light guide in the ring is adjusted to be larger than that in the center of the light guide in the ring. It is characterized by being.

  With this configuration, in the lighting device according to one embodiment of the present invention, the optical path from the light emitting element to the lens portion can be shortened by the above configuration. By shortening the optical path, the lighting device can be made thinner. Furthermore, the alignment characteristics of the light emitted from different positions of the light collecting cover can be made different so that the unevenness in each illuminance distribution can be superimposed so that the illuminance drops near an orientation angle of 0 °. Can be improved.

In another aspect, the amount of deviation may be gradually increased from the center of the in-ring light guide portion toward the periphery.
With this configuration, a continuous illuminance distribution having a single peak at an orientation angle of 0 ° can be realized.
Further, in another aspect, the concave reflecting portion is disposed on each circumference of a first concentric circle having a plurality of circumferences forming a first interval in the radial direction of the in-ring light guide portion, and the lens. The portion is arranged on each circumference of a second concentric circle having a plurality of circumferences forming a second interval in the radial direction of the light collecting cover, and the center position of the first concentric circle and the second concentric circle The center position may overlap in the main emission direction, and the first interval may be smaller than the second interval.

With such a configuration, it is possible to easily realize a configuration in which the amount of deviation of the concave antique portion gradually increases from the center of the annular portion toward the outer edge.
In another aspect, the first interval may be not less than 1.5 times and not more than 2.5 times the thickness of the light guide plate.
With this configuration, it is possible to eliminate an illuminance peak that occurs in the vicinity of an orientation angle of ± 40 ° to 45 °.

In another aspect, each of the concave reflecting portions has a conical shape with the top facing the main surface side, and the concave portion near the periphery inside the ring is the concave reflecting portion near the center inside the ring. The cone may have a higher height than the portion.
With this configuration,
Efficiency can be improved as a lighting device while maintaining a narrow orientation.

≪Other matters≫
(1) The lighting device according to the present invention is not limited to a ceiling light embedded in a ceiling. In addition to ceiling lights installed by other installation methods, it can be widely used for lighting applications such as downlights and backlights.
(2) In the illuminating device 100 which concerns on this Embodiment, the latching member 3 is not essential. The luminaire 1 may be fixed to the ceiling using screws, rivets, adhesion, or the like.

(3) A configuration in which a part of the lighting device 100 is inserted into the through hole 2a of the ceiling 2 is adopted. However, since the lighting device 100 is thin, it can be disposed on the ceiling surface of the ceiling 2 without providing the through hole 2a. In that case, the lighting device 100 can be attached to the ceiling surface using a fastening member such as a screw, an adhesive, or a double-sided tape.
(4) In the lighting device 100, the power supply unit 4 and the lighting fixture 1 are configured separately, but the present invention is not limited to this structure. That is, the illuminating device of the present invention may be configured such that the luminaire 1 includes the power supply unit 4 therein.

(5) The light emitting element 22 may be, for example, an LD (laser diode) or an EL element (electric luminescence element). The light emitting device according to the present invention may be an SMD (Surface Mount Device) type.
(6) Although the light guide plate 40 has a flat surface facing the reflecting member 30, a plurality of minute lenses may be provided to change the reflection characteristics of light passing through the light guide plate. Thereby, the light guide effect of the light guide plate can be improved.

(7) The reflection member 30 is illustrated as a plate-like member provided above the mounting substrate 20. However, it is not essential to use a reflective member for the plate member provided above the mounting substrate 20. That is, the plate-like member can be a member that does not have reflectivity. Moreover, the structure which does not insert a member above the mounting board | substrate 20 and the light guide plate 40 may be sufficient.
(8) Although the lighting device 100 has a disk shape, the lighting device 100 is not limited to a disk shape. For example, a long or rectangular lighting device may be configured by arranging a plurality of light emitting elements in a row. In this case, the base, the reflection member, the light guide plate, and the light collecting cover are formed in a long shape or a rectangular shape in the same manner as the mounting substrate. And it can implement | achieve by providing a light-incidence part in the vicinity of the long side or short side of a elongate or rectangular light-guide plate, and arrange | positioning a row-shaped light emitting element row | line | column facing a light-incidence part. Or you may provide a light-incidence part in both a long side and a short side, and may make a light emitting element row | line | column oppose.

  (9) In the illumination device 100, the lens unit 61 is a lens having an aspheric shape centering on the intersection 610 </ b> B between the central axis 61 </ b> A passing through the vertex 610 </ b> A of the lens surface 610 and parallel to the Z axis and the back surface 411 of the light guide plate 40. A configuration having a surface 610 was adopted. However, the lens unit 61 may have any shape that can concentrate the illumination light on the target surface. For example, a spherical lens, a Fresnel shape, or another configuration may be used.

  (10) In the illumination device 100, the lens unit 61 is formed on the surface of the light collection cover 60 on the side opposite to the light guide plate 40 side. However, the surface on which the lens unit 61 is formed only needs to have a shape that allows the illumination light to be collected on the target surface. For example, the lens unit 61 may be formed on the back surface 65 on the side opposite to the light guide plate 40 side. Good. In this case, the lens unit 61 does not appear on the external appearance of the illumination device 100, and a design close to that of the diffusion illumination device can be realized in the condensing illumination device. In addition, the lens portion 61 can be brought close to the concave reflecting portion 44, and further thinning can be achieved.

  (11) In the lighting device 100, the concave reflecting portion 44 is formed on the surface 411 on the side opposite to the light collection cover 60 in the light guide plate 40. However, the surface on which the concave reflection portion 44 is formed only needs to be configured so that the illumination light can be condensed on the target surface. For example, the light reflecting portion may be provided on the front-side exit surfaces 410 and 430 instead of the back-side back surfaces 411 and 431, or on both the back-side back surfaces 411 and 431 and the front-side exit surfaces 410 and 430. May be. When the concave reflecting portion 44 is formed on the light condensing center axis 61 </ b> A cover 60 side of the light guide plate 40, the concave reflecting portion 44 can be brought close to the lens portion 61, and further thinning can be achieved. However, it is preferable that the light is uniformly emitted from the entire emission surface 410 on the front side of the ring interior 41 and the entire emission surface 430 on the front side of the annular outer peripheral portion 43.

Moreover, not a recessed part but a convex part may be provided as a light reflection part, and both a recessed part and a convex part may be provided.
In addition, the light guide plate according to the present invention is not limited to a circular plate shape and is arbitrary. For example, a polygonal plate shape such as a quadrangular plate shape, a hexagonal plate shape, or an octagonal plate shape may be used. In addition, each shape of the annular portion, the inside of the ring, the annular outer peripheral portion, the element array facing portion, the inner reflecting portion, the outer reflecting portion, the inner side surface portion, and the outer side surface portion is arbitrary depending on the shape of the light guide plate. Furthermore, the arrangement of the light emitting elements and the shape of the substrate are arbitrary depending on the shape of the light guide plate.

DESCRIPTION OF SYMBOLS 1 Lighting fixture 10 Base 11 Main body part 12 Flange part 13 Inner bottom part 14 Side wall part 15 Outer bottom part 20 Mounting board (light emission part)
DESCRIPTION OF SYMBOLS 21 Substrate body 22 Light emitting element 30 Reflective member 31 Inner reflection part 32 Recessed part 33 Outer reflection part 34 Opening 40 Light guide plate 41 The inside of a ring (intra-ring light guide part)
42 annular part 43 annular outer peripheral part (annular light guide part)
44, 45 Concave reflection part 50 Diffusion cover 51 Circular ring part 52 Side wall part 53 Opening 60 Condensing cover 61 Lens part 62 Convex part 63 Lens region 100, 100A Illumination device 310, 330 Upper surface of reflection member 342, 343 Side wall 420 Element facing (Light introduction part)
422A, 422B Reflection part 423 Boundary part 424A, 424B Side face part

Claims (6)

A light emitting section in which a plurality of light emitting elements are arranged in a ring on the substrate;
A light guide plate having a light introducing portion facing the light emitting element array of the light emitting portion and a disc-shaped in-ring light guide portion for guiding the introduced light in an inner ring direction;
A disc-shaped condensing cover disposed on one main surface side of the light guide plate;
With
The light guide plate has a plurality of concave reflecting portions recessed in the back surface facing away from the main surface in order to change the optical path of the guided light toward the main surface at a plurality of locations,
The condensing cover is disposed in an optically opposing relationship with each of the plurality of concave reflecting portions and collects reflected light from each concave reflecting portion in a main emission direction perpendicular to the main surface. A plurality of light-emitting lens portions;
The individual optical facing relationship between the concave reflecting portion and the lens portion is such that, in the concave reflecting portion and the lens portion in the facing relationship, the center position of the concave reflecting portion is the center of the intra-ring light guide portion rather than the central axis of the lens portion. The illumination device is characterized in that the amount of deviation is closer to the periphery of the in-ring light guide unit, and the amount of deviation is adjusted to be larger than that in the center of the in-ring light guide unit. The lighting device according to claim 1, wherein the amount of deviation gradually increases from the center of the in-ring light guide portion toward the periphery. The concave reflection portion is disposed on each circumference of a first concentric circle composed of a plurality of circumferences forming a first interval in the radial direction of the in-ring light guide portion,
The lens portion is disposed on each circumference of a second concentric circle composed of a plurality of circumferences forming a second interval in the radial direction of the light collecting cover,
The center position of the first concentric circle and the center position of the second concentric circle overlap in the main emission direction,
The lighting device according to claim 1, wherein the first interval is smaller than the second interval. 4. The lighting device according to claim 1, wherein the first interval is not less than 1.5 times and not more than 2.5 times the thickness of the light guide plate. 5. Each of the concave reflecting portions has a conical shape with the top facing the main surface side, and the concave portion in the vicinity of the periphery of the in-ring light guide portion is in the vicinity of the center of the in-ring light guide portion. The lighting device according to claim 1, wherein the height of the cone is higher than the height of the cone.   2. The lighting device according to claim 1, wherein the plurality of lens portions are arranged so as to individually overlap each of the plurality of concave reflection portions when the light collecting cover is viewed in plan.

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