WO2014122716A1

WO2014122716A1 - Lighting device

Info

Publication number: WO2014122716A1
Application number: PCT/JP2013/007634
Authority: WO
Inventors: 直樹小谷; 一郎谷村; 有士中川; 晋二角陸; 龍馬村瀬; 福井　厚司
Original assignee: パナソニック株式会社
Priority date: 2013-02-07
Filing date: 2013-12-26
Publication date: 2014-08-14
Also published as: CN205065496U; JP2014154321A; JP5879548B2; DE112013006614T5

Abstract

A lighting device (100) is provided with a plurality of light-emitting elements (22), a light guide plate (40) that guides light emitted from the plurality of light-emitting elements within the plate thereof, and a light-collecting cover (60) that covers one part of the main surface (410) of the light guide plate. The light guide plate has an indented back surface that faces the opposite direction of one part of the main surface and comprises a plurality of concave reflecting sections (44) that reflect light guided within the light guide plate toward the main surface. The light-collecting cover comprises a plurality of lens sections (61) that are each arranged so as to maintain an optically facing relationship with each of the plurality of concave reflecting sections and that collect light reflected from each of the concave reflecting sections in a main emission direction that is perpendicular to the main surface.

Description

Lighting device

The present invention relates to an illumination device including a 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, lighting devices using semiconductor light emitting elements as light sources, such as LEDs with high efficiency and long life, have 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. 19 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 2012-1104022 A

However, in the conventional condensing type illumination device, it is necessary to secure an optical path of a predetermined length between the light source and the lens in order to condense at a constant orientation 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.

This invention is made in view of the said subject, Comprising: It aims at providing the illuminating device which can implement | achieve thin and narrow orientation.

In order to achieve the above object, an illumination device according to one embodiment of the present invention includes a plurality of light-emitting elements, a light guide plate that guides light emitted from the plurality of light-emitting elements in the plate, and a main part of the light guide plate. And a light collecting cover that covers a part of the surface. Further, the light guide plate has a plurality of concave reflecting portions in which a part of the main surface and a back surface facing away from the main surface are recessed, and light guided into the light guide plate is reflected toward the main surface. . The condensing cover is disposed in an optically opposed relationship with each of the plurality of concave reflecting portions, and the reflected light from each concave reflecting portion is in a main emission direction perpendicular to the main surface. And a plurality of lens portions for condensing light.

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

In another aspect, each concave reflecting portion may have a conical shape with a top portion facing the main surface.

Further, in another aspect, a mounting substrate in which the plurality of light emitting elements are mounted on the surface of the substrate is further provided. The plurality of light emitting elements form an annular element array on the substrate. The light guide plate includes an annular part formed in an annular shape along the element row on the mounting substrate, and an inside of the ring formed continuously with the annular part on the inner side of the annular part. The annular portion includes an element array facing portion having an incident surface on which light emitted from each of the light emitting elements is incident, and the annular portion is located on the inner side of the ring from the element array facing portion and is incident from the incident surface. An inner reflection portion having a reflection surface on which light is reflected toward the inside of the ring. Further, the inside of the ring may have a disk shape with one plane as the main surface, and the light collecting cover may have a disk shape that covers the inside of the ring.

In another aspect, a disc-shaped reflecting member is inserted between the light guide plate and the mounting substrate, and a part of the surface extends along at least the annular portion of the light guide plate and the inside of the ring. The member may take a configuration having an opening corresponding to each light emitting element.

In another aspect, the light guide plate further includes an annular plate-shaped annular outer peripheral portion connected to the annular portion toward the outer side of the annular portion. In addition, the annular portion further includes an outer reflection portion that is located closer to the annular outer peripheral portion than the element row facing portion and reflects light incident from the incident surface toward the annular outer peripheral portion. The annular outer peripheral portion has an annular outgoing surface on the main outgoing direction side and a surface facing away from the annular outgoing surface, and the light guided into the annular outer peripheral portion is the annular outgoing surface. You may take the structure which has several 2nd concave reflection part reflected in the side.

Further, in another aspect, it further includes an annular plate-shaped diffusion cover that is disposed so as to cover the annular outer peripheral portion of the light guide plate and is subjected to light scattering treatment, on the outer side of the light collecting cover. And the said diffusion cover may take the structure which diffuses the light which entered from the surface by the side of the said annular outer peripheral part of the said light-guide plate, and radiate | emits it in the said main output direction.

In another aspect, the apex angle formed by the conical surface in the conical shape may be in the range of 64 ° to 84 °.

In another aspect, the lens portion may have a flat top portion, and the conical top portion of the concave reflection portion and the flat portion overlap when viewed from the main emission direction. Good.

In another aspect, the light beam incident from the incident surface and guided to the inner reflection portion may be larger than the light beam guided to the outer reflection portion.

Further, in another aspect, a configuration in which a portion where the main surface of the light guide plate and the light collection cover are in contact with each other may be provided in the optical path from the concave reflection portion to the lens portion.

In the lighting device according to one embodiment of the present invention, the optical path length from the light emitting portion of the light source to the lens surface can be shortened by the above configuration. Thereby, in a condensing type illuminating device, thickness reduction and narrow orientation can be realized simultaneously.

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. 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 plan view of the reflecting member 30 of the luminaire 1, (b) is a cross-sectional view taken along the section AA in (a), and (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 C section enlarged view in (a). (A) is an expanded sectional view which shows the A section in FIG. 4, (b) is an expanded sectional view which shows the D section in (a). It is an expanded sectional view which shows the B 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 E 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. It is explanatory drawing which shows the condensing principle in the light-guide plate 40 of the illuminating device 100, and the condensing cover 60. FIG. It is a characteristic view which shows the calculation result of the orientation characteristic of the illuminating device 100. FIG. It is explanatory drawing which shows the condensing principle in the light guide plate 40 of the illuminating device 100A which concerns on the modification of embodiment, and the condensing cover 60A. It is a characteristic view which shows the relationship between the cross-sectional shape of the concave reflective part of 100 A of illuminating devices, and the calculation result of an orientation characteristic. It is a characteristic view which shows the relationship between the shape and the orientation characteristic of the concave reflective part 44 in 100 A of illuminating devices. It is a characteristic view which shows the relationship between the apex angle of the cone of the concave reflection part 44 in 100 A of illuminating devices, and the light beam in orientation angle +/- 10 degree. It is sectional drawing which shows the internal structure of the conventional illuminating device 800. FIG.

Hereinafter, the lighting device according to each aspect of the present invention will be described with reference to the drawings.

<< Embodiment >>
<Configuration of lighting apparatus 100>
FIG. 1 is a partial cross-sectional view illustrating a configuration and an installation example of a lighting device 100 according to an 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. 1, the lighting device 100 includes a lighting fixture 1, a leaf spring-like hooking 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. 2 is a diagram showing an external configuration and an internal configuration of the lighting fixture 1 according to the embodiment. FIG. 3 is a plan view of the luminaire 1. As shown in FIGS. 2 and 3, 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.

Note that the dotted lines in FIG. 2 indicate the positions of the built-in mounting substrate 20, light emitting element 22, and substrate body 21.

<Configuration of lighting apparatus 1>
FIG. 4 is an exploded view (assembly drawing) showing the internal configuration of the lighting fixture 1 according to the embodiment. FIG. 5 is a cross-sectional view showing the internal configuration of the lighting fixture 1 according to the embodiment. As shown in FIGS. 4 and 5, 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 includes a main body portion 11 having a two-stage bottom structure with a deep center side and a shallow peripheral edge side, and a flange portion 12 erected around the main body portion 11 (FIG. 4). 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 reflective 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. 4), and wirings 23.

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 cross-sectional view (FIG. 8) showing part A in FIG. 5, the light emitting element 22 has 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, as an example, a total of 18 light emitting elements 22 are face-up mounted on a wiring pattern using a COB (Chip on Board) technology. The diameter of the element row is about 90 mm.

Note that 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.

6A is a plan view of the reflecting member 30 of the luminaire 1 according to the embodiment, FIG. 6B is a cross-sectional view taken along the section AA in FIG. 6A, and FIG. . As shown in FIG. 6, 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. 6B).

The inner reflection portion 31 (outer reflection portion 33) is provided at a position inside (outside) the mounting position of the light emitting element 22 of the mounting substrate 20 (FIG. 5). 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 the mounting substrate 20 on the mounting substrate 20 directly above the mounting position of each light emitting element 22. When the reflecting member 30 is viewed in plan, the recessed portion 32 is formed by recessing a circumferential region having a certain radius on the upper surface of the reflecting member 30 (the surface facing the light guide plate 40) in the thickness (Z) direction (FIG. 6). (B)).

As shown in FIGS. 5, 6 A, 6 B, 8 C, and 8, 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. 8, 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 in 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 by 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. 6B, 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.7 (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 C section enlarged view in (a). As shown in FIGS. 5 and 7, the light guide plate 40 is disposed on the side opposite to the side facing the mounting substrate 20 of the reflecting member 30. 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. 5 and 8, 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 ring interior 41. 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.

Further, 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 on the inner side slightly from the outer edge of the ring interior 41 on the surface on the light collecting cover 60 side (FIG. 4). ). 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.

In the light guide plate 40, as an example, each outer surface of the ring inner portion 41 is set higher than each outer surface of the annular outer peripheral portion 43 (FIG. 5). 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 guides the emitted light of the light emitting element 22 to the inside and the outside of the light guide plate 40. In the lighting fixture 1, the annular portion 42 is inserted into the recessed portion 32 of the reflecting member 30 (FIG. 5). 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.

8 (a) is an enlarged cross-sectional view showing a portion A in FIG. 5, and (b) is an enlarged cross-sectional view showing a D portion in (a). As a specific configuration, as shown in FIG. 8, the annular portion 42 is a boundary portion existing between the element facing portion 420, the outer reflecting portion 422 A, the inner reflecting portion 422 B, and the outer reflecting portion 422 A and the inner reflecting portion 422 B. 423. As shown in FIGS. 5 and 8, the annular portion 42 has a substantially V-shaped cross-sectional shape having a certain thickness as shown in FIGS. 5 and 8. 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. Part 424B exists (FIG. 8).

The element facing portion 420 is a part that is disposed in proximity to the light emitting element 22 and is disposed to face the emission surface of the light emitting element 22. The surface shape of the element facing portion 420 facing the light emitting element 22 is a flat surface as an example here (FIG. 7B). 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. 8). 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. 8). 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 part 423 is located above the point 420c in the Z direction, which is divided approximately 1: 9 from the light incident end part 420A side on the line segment connecting the light incident end part 420A and the light incident end part 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 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.

The exit surface 410 facing the Z direction side of the ring interior 41 is subjected to a reflection process so that light guided through the ring interior 42 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 ring interior 41 to the emission surface 410 side, a plurality of concave reflection portions 44 are provided, in which a part of the back surface 411 is recessed. 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. 5, the concave reflecting 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 part 43 is a part that guides the light of the light emitting element 22 that has entered the light guide plate 40 from the annular part 42 to the outside of the mounting position of the light emitting element 22 and reflects it in the Z direction. 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 reflecting 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. 5, 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. 9 is an enlarged cross-sectional view showing a portion B in FIG. As shown in FIG. 9, a plurality of concave reflecting portions 44 are provided on the back surface of the light guide plate 40, with a part of the back surface 411 being recessed. 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 an optical facing relationship” means that the light reflected by the concave reflecting portion 44 and incident on the lens portion 61 is in a positional relationship where it is condensed as illumination light. In the present embodiment, as an example, each concave reflecting portion 44 has a configuration in which the center line of the cone is arranged at a position where the center line of the lens portion 60 provided on the light collecting cover 60 substantially coincides with each other. It was. However, for example, the plurality of lens units 61 may be configured such that each of the plurality of concave reflection units 44 and the lens unit 61 individually overlap when viewed in plan in the XY direction. 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. 10 is a schematic diagram showing 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 an apex angle θ, a height h, and a central axis 44A. The conical portion is a space whose bottom surface is an opening. The apex angle θ is 64 ° to 84 °, more preferably 76 ° ± 1 °, h is 0.4 to 0.7 mm, and r at the tip is 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 vertical 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 will be 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.

11A is a plan view of the light collection cover 60 of the luminaire 1, FIG. 11B is an enlarged view of an E portion in FIG. 11A, FIG. 11C is a side view, and FIG. . As shown in FIGS. 5 and 11, the condensing cover 60 has a disc shape, and includes a lens region 63 that covers the exit surface 410 of the inner ring 41 of the light guide plate 40, and a peripheral portion 64 that is positioned on the outer periphery of the lens region. Have 5 and 11, the range indicated by the symbol W ₆₃ is the lens region 63, and the range indicated by the symbol W ₆₄ is the peripheral portion 64. In the present embodiment, the lens region 63 is about 80 mm.

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. 5).

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. 11A, the lens region 63 of the light collecting cover 60 has a plurality of lens portions 61. As shown in FIG. 11B, the lens unit 61 is positioned so that the center of the lens unit 61 is a concentric circle having a pitch p between the circles with a center 600A of the lens region 63 as a reference. Be placed. In the present embodiment, the pitch p is about 3 mm, for example. 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. 12 is a schematic diagram illustrating a cross section of the lens portion 61 in the light collection cover 60 of the lighting device 100 and the concave reflection portion 44 in the light guide plate 40. 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. 12, the lens portion 61 has a lens surface 610 having an aspherical shape centered on an intersection 44 B between the central axis 44 A of the cone in the concave reflection portion 44 described above and the back surface 411 of the light guide plate 40. 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.

(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. 5 and 11, the light collecting cover 60 has an annular shape having an annular portion 51 in which an opening 53 for exposing the lens region 63 of the light collecting 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. 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. 5, 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 the 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.

The 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. 6) 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 main body 51 of the diffusion cover 50 that has been subjected to light scattering treatment, and finally emitted as illumination light to the outside.

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 toward.
<Effects produced by lighting device 100>
When the illumination device 100 is driven, the following effects can be expected.

(Orientation characteristics)
[Specific effects]
FIG. 13 is an explanatory diagram showing a light collection principle in the light guide plate 40 and the light collection cover 60 of the illumination device 100. As shown in FIG. 13, the light emitted from the light emitting element 22 is reflected in the direction of the light emission surface 410 by the concave reflecting portion 44 formed on the back surface 411 of the light guide plate 40. At this time, when light p ₁ , p ₂ , p ₃ , p ₄ , and p ₅ emitted from the conical center 44A of the concave reflecting portion 44 are taken into consideration, they are incident on the light collecting cover 60 and then the lens portion 61. Is converted into parallel light ahead of the main emission direction. However, the reflecting surface of the concave reflecting portion 44 is at a position shifted from the center 44A, and light reflected from the center 44A, for example, q ₁ , q ₂ , q ₃ , q ₄ or r ₁ , r ₂ , r ₃ , r After being incident on the light collecting cover 60, the light ₄ is converted into light inclined with respect to the front in the main emission direction by the lens unit 61. 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 44 is 0.8 mm, the intensity peak of the emitted light occurs at an angle of about ± 5 °.

At this time, for example, the peak-to-peak distance X ₀ of the illuminance on the target surface about 2 m ahead from the light source is about 350 mm. Similarly, illumination light that has been collected with a peak of illuminance at an orientation angle of about ± 5 ° is irradiated onto the target surface from the plurality of lens portions 61 existing in the lens region 63 of the light collecting cover 60. At this time, since the size of the lens region 63 is about 80 mm in diameter, the centers of illumination light from the plurality of lens portions 61 are also distributed within a range of about 80 mm in diameter on the symmetry plane.

[Performance confirmation result]
About the orientation characteristic of the illuminating device 100, the calculation by optical simulation was performed. FIG. 14 is a characteristic diagram showing the calculation result of the orientation characteristic of the illumination device 100. FIG. 14 (a) shows the illuminance distribution 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 2m 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.

As shown in FIGS. 14A and 14B, in the illumination device 100, the 1/2 beam angle θ1, which is one of the scales for evaluating the orientation, 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 luminaire 100, the ½ beam angle can be reduced to 25 °. By further reducing the diameter of the bottom surface of the cone of the concave reflecting portion 44 of the light guide plate 40, it is possible to further reduce the 1/2 beam angle.

(About the thickness of the lighting device 100)
In the lighting device 100, the total thickness Y1 of the lighting device 100 shown in FIG. 5 was 18 mm, the thickness Y2 of the portion inserted into the through hole 2a of the ceiling 2 was 8 mm, and the thickness Y3 of the portion exiting from the ceiling 2 was 10 mm. . In the illuminating device 100, the ring inner portion 41 and the annular outer peripheral portion 43 of the light guide plate 40 have different heights in terms of design. By making the height of the ring interior 41 and the height of the annular outer peripheral portion 43 in the light guide plate 40 the same, it is possible to further reduce the thickness. In this case, the total thickness Y1 of the lighting device 100 is 13 mm.

In the conventional condensing type illumination device using the Fresnel lens, the length of the optical path from the light emitting part of the light source to the lens surface is approximately 13.6 mm when the lens aperture is approximately 80 mm. The / 2 beam angle was 80 ° (Patent Document 1). Further, in the case of a lens aperture of 162 mm where the 1/2 beam angle is 45 °, the optical path length from the light emitting part of the light source to the lens surface needs to be about 27 mm (Patent Document 1).

Furthermore, in this embodiment, the total thickness Y1 of the lighting device can be reduced to about 6 mm by adopting a configuration in which the light emitting element 22 is incident from the side surface of the light guide plate. Alternatively, the total thickness Y1 of the lighting device can be similarly reduced to about 6 mm by reducing the thickness of the reflector and the base in the present embodiment and adopting a configuration in which the total thickness is 2 mm.

(To prevent striped brightness unevenness)
In a concentrating illumination device using a lens, the thickness of the lens increases when narrow orientation is achieved. In order to prevent this, it is necessary to use a Fresnel lens and increase the number of lens divisions. However, when a Fresnel lens is used, the illumination light is divided and striped luminance unevenness occurs. On the other hand, in the illumination device 100 according to the present embodiment, each lens unit 61 irradiates illumination light condensed to a predetermined size on the target surface, and the illumination light emitted from the plurality of lens units 61. An optical system in which is superimposed is adopted. Therefore, the striped luminance unevenness does not occur in the illumination light with the thinning of the lens. Therefore, striped luminance unevenness can be prevented while realizing narrow orientation and thinning of the lens.

(Brief Summary)
As described above, the illumination device 100 has the above-described configuration, and in the concentrating illumination device, an orientation angle of ½ beam angle of 25 ° and a total thickness of the illumination device of 18 mm can be realized. By adopting this method, it is possible to provide a lighting device that is thin and can realize narrow orientation.

<< Modification 1 >>
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 lighting device 100 according to the above-described embodiment, the lens unit 61 is configured as shown in FIG. That is, the lens unit 61 has a lens surface 610 having an aspherical shape centering on an intersection 44B between the conical central axis 44A of the concave reflection unit 44 and the back surface 411 of the light guide plate 40. However, the lens unit 61 may have any shape as long as it can collect the illumination light on the target surface and can be modified as follows.

FIG. 15 is an explanatory diagram illustrating a light collection principle in the light guide plate 40 and the light collection cover 60A of the illumination device 100A according to the modification of the embodiment. As shown in FIG. 15, in the illumination device 100A according to Modification 1, the lens unit 61A in the light collecting cover 60A is obtained by changing the lens surface 610 of the lens unit 61 used in the illumination device 100 as follows. . That is, the aspherical shape of the lens surface 610, relative to the central axis 44A of the cone at the concave reflecting portion 44, each offset by X ₁ in the left-right direction in FIG. 15, the top of the lens surface of the wide 2 × X ₁ The structure which provided the flat part 66 is taken. In the present embodiment, the offset X ₁ is about 0.1 to 0.2 mm, and the diameter of the flat portion is 0.2 to 0.4 mm.
<Effects produced by lighting device 100A>
When the illumination device 100A is driven, the following effects can be expected.

(Orientation characteristics)
[Specific effects]
As shown in FIG. 14, the light emitted from the light emitting element 22 is reflected in the direction of the light emission surface 410 by the concave reflecting portion 44 formed on the back surface 411 of the light guide plate 40. At this time, when light s ₁ , s ₂ , s ₃ , s ₄ , and s ₅ emitted from the conical center 44A of the concave reflecting portion 44 are taken into consideration, they are incident on the light collecting cover 60 and then the lens portion 61. Is converted into parallel light ahead of the main emission direction. However, the reflecting surface of the concave reflecting portion 44 is at a position shifted from the center 44A.

In the first modification, among the light t ₁ , t ₂ , t ₃ , t ₄ , t ₅ reflected from the slope of the concave reflecting portion located to the left from the center 44A, the light t in the main emission direction ₃ is emitted in the main emission direction through the flat portion 66 as it is. On the other hand, light other than t ₃ , t ₁ , t ₂ , t ₄ , t ₅ is incident on the light collecting cover 60 and then emitted by the lens unit 61 in a direction inclined with respect to the front in the main emission direction.

Similarly, out of the light u ₁ , u ₂ , u ₃ , u ₄ , u ₅ reflected from the slope of the concave reflecting portion 44 located to the right from the center 44A, the light u ₃ in the main emission direction. Is directly emitted through the flat portion 66 in the main emission direction. On the other hand, light other than u ₃ , u ₁ , u ₂ , u ₄ , u ₅ is incident on the light collection cover 60 and then emitted by the lens unit 61 in a direction inclined with respect to the front in the main emission direction. Therefore, t ₁ , t ₂ , t ₄ , t _5, and u ₁ , u ₂ , u ₄ , excluding the light t ₃ and u ₃ in the main emission direction from the light reflected from the concave reflector 44. The peak of the light intensity of u ₅ exists at a position slightly deviated from the orientation angle 0 °. For example, when the diameter of the bottom surface of the cone in the concave reflection portion 44 is 0.8 mm, t ₁ , t ₂ , t ₄ , t ₅ and u ₁ , u ₂ , u ₄ , A peak of the light intensity of u ₅ occurs.

However, the light t ₃ and u ₃ emitted in the main emission direction from the concave reflection portion 44 through the flat portion 66 has the highest intensity among the light emitted from the concave reflection portion 44, so that the orientation angle is 0 °. A peak of the intensity of the entire emitted light occurs at the angle. Therefore, the light is condensed with an illuminance peak at an orientation angle of about 0 °. As a result, it is possible to improve the drop in illuminance in the vicinity of an orientation angle of 0 ° in the lighting device 100 shown in FIGS. 14 (a) and 14 (b). At this time, the peak-to-peak distance of illuminance on the symmetry plane of the illumination light is zero. Similarly, illumination light that has been collected with a peak of illuminance at an orientation angle of about 0 ° is irradiated onto the target surface from the plurality of lens portions 61A in the light collection cover 60A.

[Performance confirmation result]
The orientation characteristics of the lighting device 100A were calculated by optical simulation. FIG. 16 is a characteristic diagram showing the calculation result of the orientation characteristic of the illumination device 100A. FIG. 16A shows an illumination angle distribution when the illumination device 100A is placed at the center O and is turned on with the 0 ° direction as the main emission direction and the target surface 2m ahead of the light source is irradiated. It is the characteristic view shown on the circumference coordinate by making a radial direction illuminance. Further, (b) is a characteristic diagram shown in orthogonal coordinates.

As shown in FIGS. 16A and 16B, in the illumination device 100A, the ½ beam angle θ2 is 22 °.

FIG. 16 is a characteristic diagram showing the relationship between the shape and the orientation characteristic of the concave reflecting portion 44 in the illumination device 100A. The distribution of illuminance on the exit surface 410 of the light guide plate 40 when the apex angles in the conical shape of the concave reflecting portion 44 are 60 °, 76 °, and 84 ° was obtained by simulation. As shown in FIG. 16, the change occurs at an orientation angle of 15 ° or less. And when the apex angle was set to 76 °, it was confirmed that the illuminance near the peak increased most. FIG. 18 is a characteristic diagram showing the relationship between the apex angle of the concave reflecting portion 44 and the luminous flux at an orientation angle of ± 10 ° in the illumination device 100A. As a result, the luminous flux at an orientation angle of ± 10 ° close to a ½ beam angle in the illumination device 100A exhibits a peak at an apex angle of 76 °. Further, the luminous flux is within about 98% of the peak value in the range of the apex angle of 64 ° to 84 °. Therefore, the apex angle in the conical shape of the concave reflecting portion 44 is preferably in the range of 64 ° to 84 °, and more preferably in the vicinity of 76 ° (about ± 1 °).

≪Summary≫
As described above, in lighting apparatus 100 according to the present embodiment, a plurality of light emitting elements 22, a light guide plate 40 that guides light emitted from the plurality of light emitting elements within the plate, and a main surface of the light guide plate And a light collecting cover 60 that covers a part of 410. The light guide plate has a plurality of concave reflection portions 44 in which a part of the main surface and the back surface facing away are recessed, and light guided into the light guide plate is reflected toward the main surface. The condensing cover is arranged in an optically opposed relationship with each of the plurality of concave reflecting portions and condenses the reflected light from each concave reflecting portion in the main emission direction perpendicular to the main surface. A plurality of lens portions 61 are provided. With this configuration, the optical path length from the light emitting portion of the light source to the lens surface can be shortened compared to a configuration using a conventional Fresnel lens. As a result, it is possible to simultaneously realize thinning and narrow orientation in a concentrating illumination device.

≪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) The hooking member 3 is not essential in the lighting device 100 according to the present embodiment. 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 reflecting member 30 is exemplified 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 illuminating device 100, the lens unit 61 has a lens surface 610 having an aspherical shape centering on the intersection 44 B between the central axis 44 A of the cone in the concave reflection unit 44 and the back surface 411 of the light guide plate 40. did. 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 collecting 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 66 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 illumination device 100, the concave reflecting portion 44 is formed on the surface 411 on the side of the light guide plate 40 that is opposite to the light collection cover 60. 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 reflection portion 44 is formed on the light guide plate 40 on the diffusion cover 60 side, the concave reflection portion 44 can be brought close to the lens portion 61, and further reduction in thickness 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.

Further, not the concave portion but a convex portion may be provided as the light reflecting portion, or both the concave portion and the convex portion may be provided.

Further, 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 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 Ring Internal part 42 Annular part 43 Annular outer

peripheral part

44, 45 Concave reflection part 50 Diffusion cover 51 Annular part 52 Side wall part 53 Opening 60 Condensing cover 61 Lens part 62 Convex part 63 Lens area 66 Flat part 100,

100A Illumination device

310, 330

Upper surface

342, 343 Side wall 420

Element facing portion

420A, 420B Light incident end 420C Position on

element facing portion

422A, 422B Reflecting portion 423

Boundary portion

424A, 424B Side surface portion

Claims

A plurality of light emitting elements;
A light guide plate for guiding light emitted from the plurality of light emitting elements in the plate;
A light collecting cover covering a part of the main surface of the light guide plate,
The light guide plate has a plurality of concave reflecting portions in which a part of the main surface and a back surface facing away from the main surface are recessed, and light guided into the light guide plate is reflected toward the main surface,
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 lighting device comprising a plurality of lens portions that emit light.
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.
2. The illumination device according to claim 1, wherein each of the concave reflecting portions has a conical shape with a top portion facing the main surface side.
Furthermore, a mounting substrate in which the plurality of light emitting elements are mounted on the surface of the substrate,
The plurality of light emitting elements form an annular element array on the substrate,
The light guide plate includes an annular portion formed in an annular shape along the element row on the mounting substrate, and an inside of the ring formed continuously with the annular portion on the inner side of the annular portion,
The annular portion includes an element array facing portion having an incident surface on which light emitted from each of the light emitting elements is incident, and light incident from the incident surface located on the inner side of the ring from the element array facing portion. An inner reflection portion having a reflection surface that is reflected toward the inside of the ring,
The inside of the ring is disk-shaped with one plane as the main surface,
The lighting device according to claim 1, wherein the light collection cover has a disk shape covering the inside of the ring.
Between the light guide plate and the mounting substrate, a disc-shaped reflection member is inserted between the light guide plate and at least an annular portion of the light guide plate and the inside of the ring, and the reflection member is connected to each light emitting element. The lighting device according to claim 4, wherein each of the lighting devices has a corresponding opening.
The light guide plate further has an annular plate-shaped annular outer peripheral portion connected to the annular portion toward the outer side of the annular portion,
The annular portion further includes an outer reflection portion that is located closer to the annular outer peripheral portion than the element row facing portion and that reflects light incident from the incident surface toward the annular outer peripheral portion;
The annular outer peripheral portion has an annular exit surface on the main exit direction side and a surface opposite to the annular exit surface, and light guided into the annular outer periphery portion is directed to the annular exit surface side. The lighting device according to claim 4, further comprising a plurality of second concave reflecting portions to be reflected.
On the outer side of the light collecting cover, it further has an annular plate-shaped diffusion cover that is disposed so as to cover the annular outer peripheral portion of the light guide plate and subjected to light scattering treatment,
The illumination device according to claim 6, wherein the diffusion cover diffuses light incident from a surface on the annular outer peripheral portion side of the light guide plate and emits the light in the main emission direction.
4. The illumination device according to claim 3, wherein an apex angle formed by the conical surface in the conical shape is included in a range of 64 ° to 84 °.
The illumination device according to claim 1, wherein the top of the lens portion has a flat portion, and the top of the cone and the flat portion of the concave reflection portion overlap each other when viewed from the main emission direction. .
The illumination device according to claim 6, wherein a light beam incident from the incident surface and guided to the inner reflection part is larger than a light beam guided to the outer reflection part.
The illumination according to any one of claims 1 to 10, wherein a portion where the main surface of the light guide plate and the light collecting cover are in contact with each other exists in an optical path from the concave reflection portion to the lens portion. apparatus.
A mounting substrate having a plurality of light emitting elements and a substrate, wherein the plurality of light emitting elements are mounted on the surface of the substrate to form an annular element array;
An annular portion formed in an annular shape along the element row on the mounting substrate, and a disk-shaped annular interior formed continuously from the annular portion inside the annular portion and having one plane as a main surface A light guide plate for guiding the light emitted from the plurality of light emitting elements in the plate,
A disc-shaped condensing cover that covers a part of the main surface, and the light guide plate has a light that is guided into the light guide plate with a back surface facing away from a part of the main surface. Has a plurality of concave reflecting portions that are reflected toward the main surface, and the condensing cover is individually disposed in an optically facing relationship with each of the plurality of concave reflecting portions, and each concave shape. An illuminating device comprising: a plurality of lens portions for condensing reflected light from a reflecting portion in a main emission direction perpendicular to the main surface.