CN107763516B - Lighting apparatus - Google Patents

Abstract

Provided is a lighting device capable of improving the utilization efficiency of light from a light-emitting element. The lighting device (2) is provided with a second light-emitting element (46) and a light guide plate (22) for guiding light from the second light-emitting element (46) in a predetermined direction. The light guide plate (22) includes: an incident part (22c) on which light from the second light-emitting element (46) is incident; an emission unit (22d) that emits light that enters the incidence unit (22 c); and a light guide section (22b) that extends from the incident section (22c) to the emission section (22d) and that has a first reflection surface (70) and a second reflection surface (72) on the outer peripheral surface. The first reflecting surface (70) forms a parabola having a focal point F in a cross section when the light guide part (22b) is cut off by a virtual plane, and the second reflecting surface (72) is arranged on a side closer to the light emitting part (22d) than the first reflecting surface (70) in the cross section and is arranged at a position intersecting with virtual straight lines (76, 78) passing through the first reflecting surface (70) and the focal point F.

Description

Lighting apparatus

Technical Field

The present invention relates to a lighting device using a light guide plate.

Background

A lighting fixture using a light guide plate is known (for example, see patent document 1). The light guide plate includes an incident portion into which light from the light emitting element enters, an exit portion from which light entering the incident portion exits, and a light guide portion formed between the incident portion and the exit portion. The light guide portion extends from the incident portion to the emission portion. The light entering the light guide unit from the incident unit is reflected by the outer peripheral surface (convex surface) of the light guide unit and guided to the light emitting unit.

Patent document 1: japanese patent laid-open publication No. 2013-101858

However, the conventional lighting apparatus described above has a problem that propagation loss of light occurs in the light guide portion, and the utilization efficiency of light from the light emitting element is lowered.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a lighting fixture capable of improving the utilization efficiency of light from a light emitting element.

In order to solve the above problem, a lighting fixture according to an embodiment of the present invention includes: a light emitting element; and a light guide plate for guiding light from the light emitting element in a predetermined direction, the light guide plate including: an incident portion on which light from the light emitting element is incident; an exit portion that exits light incident on the incident portion; and a light guide portion that is formed between the incident portion and the emission portion, and that extends from the incident portion to the emission portion in a curved manner, the light guide portion having, on an outer peripheral surface, a first reflection surface and a second reflection surface for reflecting and guiding light incident on the incident portion toward the emission portion, the first reflection surface forming a parabola having a focal point on a cross section obtained when the light guide portion is cut by a virtual plane, and the second reflection surface being arranged on a side closer to the emission portion than the first reflection surface on the cross section and at a position intersecting a virtual straight line passing through the first reflection surface and the focal point.

The lighting device according to one embodiment of the present invention can improve the utilization efficiency of light from the light-emitting element.

Drawings

Fig. 1 is a perspective view showing an appearance of a floor side of a lighting fixture according to an embodiment.

Fig. 2 is a perspective view showing an appearance of the lighting apparatus according to the embodiment on the ceiling side.

Fig. 3 is an exploded perspective view showing the lighting apparatus according to the embodiment with the diffusion cover removed.

Fig. 4 is an exploded perspective view showing the lighting fixture according to the embodiment in a state where the decorative cover, the light guide plate, and the reflection member are removed.

Fig. 5 is an exploded perspective view illustrating the lighting fixture according to the embodiment.

Fig. 6 is a sectional view taken along line VI-VI of fig. 1.

Fig. 7 is a sectional view showing a part of fig. 6 in an enlarged manner.

Fig. 8 is a plan view illustrating the lighting fixture according to the embodiment in a state where the decorative cover, the light guide plate, the reflecting member, and the diffusion cover are omitted.

Fig. 9 is a plan view showing the lighting fixture according to the embodiment in a state where the lens cover is omitted from fig. 8.

Fig. 10 is a diagram showing the light guide plate according to the embodiment extracted.

FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 10 (a).

Fig. 12 is an enlarged sectional perspective view illustrating an incident portion of the light guide plate according to the embodiment.

Fig. 13 is an enlarged perspective view showing a part of the light guide plate according to the modification of the embodiment.

Description of the symbols

2 Lighting device

22. 22A light guide plate

22a opening part

22b light guide part

22c incident part

22d injection part

22e branched light guide part

46 second light emitting element (light emitting element)

58. 64 center shaft

60 prism shape (micro structure part)

62 prism structure

66 inclined part

68 bending part

70 first reflecting surface

72. 72A second reflecting surface

76. 78 virtual straight line

80. Rough surface of 80A

82 concave part

F focus

Detailed Description

Hereinafter, embodiments of the present invention will be described. The embodiments described below are preferred specific examples of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, and the like shown in the following embodiments are merely examples, and do not limit the gist of the present invention. Therefore, among the components of the following embodiments, components that are not described in the embodiments showing the uppermost concept of the present invention will be described as arbitrary components.

Each drawing is a schematic drawing, and is not necessarily a strictly illustrated drawing. In the drawings, substantially the same components are denoted by the same reference numerals, and redundant description is omitted or simplified.

(embodiment mode)

The following describes a lighting fixture according to an embodiment.

[1. Structure of Lighting apparatus ]

[ 1-1. integral Structure of Lighting apparatus ]

First, the overall configuration of the lighting fixture 2 according to the embodiment will be described with reference to fig. 1 to 5. Fig. 1 is a perspective view showing an appearance of a lighting fixture 2 according to an embodiment on a floor side. Fig. 2 is a perspective view showing an appearance of the lighting apparatus 2 according to the embodiment on the ceiling 4 side. Fig. 3 is an exploded perspective view showing the lighting fixture 2 according to the embodiment with the diffusion cover 26 removed. Fig. 4 is an exploded perspective view showing the lighting fixture 2 according to the embodiment in a state where the trim cover 20, the light guide plate 22, and the reflection member 24 are removed. Fig. 5 is an exploded perspective view illustrating the lighting fixture 2 according to the embodiment.

The lighting fixture 2 is a ceiling lamp that is installed on a ceiling 4 (see fig. 5) of a building such as a house, for example, and illuminates a space 6 (see fig. 6 described later) inside the building. As shown in fig. 1 to 5, the lighting fixture 2 includes a fixture main body 8, a fixture mounting member 10, a power supply unit 12, a reflection cover 14, a light emitting module 16, a lens cover 18, a decorative cover 20, a light guide plate 22, a reflection member 24, and a diffusion cover 26.

Hereinafter, each constituent element of the lighting fixture 2 will be described in detail with reference to fig. 1 to 12. In fig. 1 to 12, the negative side of the Z axis indicates the ceiling 4 side, and the positive side of the Z axis indicates the floor surface (not shown) side. For convenience of explanation, the lighting fixture 2 is shown in an upside-down posture opposite to the posture in normal use in fig. 1 and 3 to 7.

[ 1-2. apparatus body ]

The apparatus main body 8 will be described with reference to fig. 2, 5, 6, and 7. Fig. 6 is a sectional view taken along line VI-VI of fig. 1. Fig. 7 is a sectional view showing a part of fig. 6 in an enlarged manner.

The device main body 8 is a casing for supporting the power supply unit 12 and the reflection cover 14. As shown in fig. 2, 5, and 6, the device body 8 is formed in a ring shape having a circular opening 8a at the center. As shown in fig. 5 and 7, a flange 8b for supporting the reflection cover 14 is formed on the outer peripheral portion of the device main body 8. The device body 8 is formed in the above-described shape by press working a thin metal plate such as an aluminum plate or a steel plate.

As shown in fig. 6, a holder 28 for attaching the device main body 8 to the device attachment member 10 (described later) is fixed to an edge portion of the opening 8a of the device main body 8. The retainer 28 extends from an edge of the opening 8a of the device body 8 toward the floor. As will be described later, the instrument attachment member 10 is detachably fitted in the holder 28.

As shown in fig. 5 and 6, an insulating case 30 for supporting the reflection cover 14 is fixed to one surface (floor-side surface) of the device body 8. The insulating housing 30 is formed in a substantially rectangular tubular shape and is disposed at a position surrounding the holder 28. The insulating case 30 is formed of an insulating material such as resin.

As shown in fig. 2 and 6, a plurality of cushioning members 32 made of, for example, polyurethane are attached to the other surface (the surface on the ceiling 4 side) of the device body 8. The plurality of cushioning members 32 are arranged at equal intervals along the circumferential direction of the device main body 8. When the lighting fixture 2 is installed on the ceiling 4 as described later, the plurality of cushioning members 32 are sandwiched between the fixture body 8 and the ceiling 4, and the looseness of the fixture body 8 is suppressed.

[ 1-3. appliance mounting Member ]

Next, the instrument attachment member 10 will be described with reference to fig. 2, 5, and 6. The instrument attachment member 10 is an adapter for detachably attaching the instrument body 8 to a ceiling lamp line box body 34 (see fig. 5) provided in the ceiling 4.

As shown in fig. 2, 5, and 6, the instrument attachment member 10 is formed in a substantially cylindrical shape, and is detachably fitted in the holder 28 of the instrument main body 8. The instrument attachment member 10 is detachably attached to the ceiling lamp line box body 34.

In setting the lighting fixture 2 to the ceiling 4, the user first mounts the fixture mounting part 10 to the ceiling rose box body 34. Then, the user pushes the appliance main body 8 toward the ceiling 4 so that the appliance attachment member 10 is inserted into the holder 28 of the appliance main body 8, thereby fitting the holder 28 to the appliance attachment member 10. Accordingly, the fixture body 8 is attached to the ceiling 4 via the fixture attachment member 10 and the ceiling lamp string box body 34, and the lighting fixture 2 is installed on the ceiling 4.

The ceiling lamp line box body 34 is electrically connected to a commercial power supply (not shown) disposed on the back surface of the ceiling 4 via an electric wire (not shown). The lighting fixture 2 is provided at the ceiling 4, so that alternating current from a commercial power supply is supplied to the lighting fixture 2 via an electric wire and the ceiling rose box body 34.

[ 1-4. Power supply Unit ]

Next, the power supply unit 12 will be described with reference to fig. 5. The power supply unit 12 is a unit for generating power for lighting the light emitting module 16. As shown in fig. 5, the power supply unit 12 has a substrate 36, and a plurality of circuit components 38 mounted on the substrate 36.

The substrate 36 is a printed wiring board for mounting a plurality of circuit components 38, and is formed in a substantially L-shape. The substrate 36 is mounted on one surface of the device body 8 so that the plurality of circuit components 38 face the floor side.

Each of the plurality of circuit components 38 is a power supply circuit component constituting a power supply circuit for generating power for causing the light emitting module 16 to emit light. The plurality of circuit components 38 include, for example, a) a capacitive element such as an electrolytic capacitor or a ceramic capacitor, b) a resistive element such as a resistor, c) a rectifier circuit element, d) a coil element, e) a choke coil (choke transformer), f) a noise filter, g) a semiconductor element such as a diode or an integrated circuit element, and the like.

The plurality of circuit components 38 convert alternating current supplied from the commercial power supply via electric wires into direct current. The direct current generated by the plurality of circuit parts 38 is supplied to the light emitting module 16, so that the light emitting module 16 emits light.

The plurality of circuit components 38 may include circuit components constituting other circuits in addition to the power supply circuit components described above. For example, the plurality of circuit components 38 may include a driving circuit component constituting a dimming circuit, a boosting circuit, or the like, or may include a communication circuit component (communication module) constituting a communication circuit, or the like.

[ 1-5. reflection case ]

Next, the reflection cover 14 will be described with reference to fig. 4 to 7. The reflection cover 14 is a cover for reflecting light from the light emitting module 16. The reflection cover 14 also functions as a heat sink for dissipating heat from the light emitting module 16.

As shown in fig. 4 to 6, the reflection cover 14 is formed in a ring shape having a substantially rectangular opening 14a in the center. As shown in fig. 7, a flange portion 14b is formed on the outer peripheral portion of the reflection cover 14. The reflection cover 14 is formed in the above-described shape by press working a thin metal plate such as an aluminum plate or a steel plate. On one surface (floor-side surface) of the reflection cover 14, a white paint is applied or a reflective metal material is deposited to improve reflectivity and improve light extraction efficiency.

As shown in fig. 6 and 7, the reflection cover 14 is disposed so as to cover one surface of the device main body 8. Flange portion 14b of reflection cover 14 is attached to flange portion 8b of device body 8 by a plurality of screws 40. The edge of the opening 14a of the reflection cover 14 is supported by the front end of the insulating housing 30.

[ 1-6. light-emitting Module ]

Next, the light-emitting module 16 will be described with reference to fig. 4 to 9. Fig. 8 is a plan view illustrating the lighting fixture 2 according to the embodiment in a state where the decorative cover 20, the light guide plate 22, the reflective member 24, and the diffusion cover 26 are omitted. Fig. 9 is a plan view showing the lighting fixture 2 according to the embodiment in a state where the lens cover 18 is omitted from fig. 8.

The light emitting module 16 is a light source for emitting white light, for example. As shown in fig. 4 to 9, the light emitting module 16 includes a plurality of substrates 42, and a plurality of first light emitting elements 44 and a plurality of second light emitting elements 46 (an example of a light emitting element) mounted on each of the plurality of substrates 42.

As shown in fig. 9, the substrate 42 is a printed wiring board for mounting the plurality of first light emitting elements 44 and the plurality of second light emitting elements 46, and is formed in an arc shape. Each of the plurality of substrates 42 is attached to one surface of the reflection cover 14 by a plurality of screws 48 so as to surround the opening 14a of the reflection cover 14. Accordingly, the plurality of substrates 42 are arranged in a ring shape along the circumferential direction of the light guide plate 22 (described later).

As shown in fig. 9, a pair of connectors 50 are attached to both ends of the substrate 42 in the circumferential direction. The opposed connectors 50 of the adjacent pair of substrates 42 are electrically connected to each other via leads 52. The pair of connectors 50 facing each other of the other adjacent pair of substrates 42 is electrically connected to the substrate 36 of the power supply unit 12 via the lead 54.

For example, a resin substrate, a metal substrate, a ceramic substrate, a glass substrate, or the like can be used as the substrate 42. The substrate 42 is not limited to a rigid substrate, and may be a flexible substrate.

The plurality of first light emitting elements 44 are mounted on the inner peripheral portion of the substrate 42. Specifically, the plurality of first light-emitting elements 44 are arranged in 3 rows in the radial direction of the substrate 42 on the inner peripheral portion of the substrate 42. In each column, the plurality of first light emitting elements 44 are arranged with intervals in the circumferential direction of the substrate 42. Accordingly, the plurality of first light-emitting elements 44 are arranged in a ring shape as the entire light-emitting module 16.

The plurality of second light emitting elements 46 are mounted on the outer peripheral portion of the substrate 42. Specifically, the plurality of second light-emitting elements 46 are arranged in, for example, only 1 row at intervals in the circumferential direction of the substrate 42 at the outer circumferential portion of the substrate 42. Accordingly, the plurality of second light-emitting elements 46 are arranged in a ring shape as the whole light-emitting module 16.

Each of the first light Emitting element 44 and the second light Emitting element 46 is, for example, a Surface Mount Device (SMD) type white led (light Emitting diode) element which is packaged. That is, each of the first light emitting element 44 and the second light emitting element 46 includes a white resin package (container) having a recess, an LED chip mounted on the bottom surface of the recess of the package at a time, and a sealing member incorporated in the recess of the package. The LED chip is, for example, a blue LED chip emitting blue light. The sealing member contains a yellow phosphor such as YAG (yttrium aluminum garnet) that emits fluorescence using blue light from the blue LED chip as excitation light.

In this manner, each of the first light emitting element 44 and the second light emitting element 46 is a B-Y type white LED element composed of a blue LED chip and a yellow phosphor. Specifically, the yellow phosphor contained in the sealing member absorbs a part of the blue light from the blue LED chip, and excites the blue LED chip to emit yellow light. The emitted yellow light and the blue light that is not absorbed by the yellow phosphor are mixed, thereby producing white light. In this manner, white light is emitted from each of the first light-emitting element 44 and the second light-emitting element 46.

In the present embodiment, the first light-emitting element 44 and the second light-emitting element 46 both emit white light, but may emit light of different colors (wavelengths) from each other. For example, the first light emitting element 44 may be made to emit white light, and the second light emitting element 46 may be made to emit bulb color light.

[ 1-7. lens cover ]

Next, the lens cover 18 will be described with reference to fig. 3 to 8. The lens cover 18 is an optical member for enlarging the light distribution angle of light from each of the plurality of first light-emitting elements 44.

As shown in fig. 3 to 8, the lens cover 18 is formed in a ring shape and is made of a material having light transmittance (for example, transparent acrylic resin or the like). As shown in fig. 8, the lens cover 18 is attached to one surface of the reflection cover 14 by a plurality of screws 56 so as to cover an inner peripheral portion of each of the plurality of substrates 42. At this time, the lens cover 18 covers the plurality of first light emitting elements 44 of each of the plurality of substrates 42, and does not cover the plurality of second light emitting elements 46 of each of the plurality of substrates 42.

The lens cover 18 has a plurality of lens portions 18a formed therein corresponding to the plurality of first light-emitting elements 44. The light from each of the plurality of first light-emitting elements 44 passes through the corresponding lens portion 18 a. At this time, each of the plurality of lens portions 18a enlarges the light distribution angle of the transmitted light.

[ 1-8. decorative cover ]

Next, the trim cover 20 will be described with reference to fig. 5 to 7. The decorative cover 20 is a cover for decorating by covering the reflection cover 14 and the appliance main body 8 from the side.

As shown in fig. 5 to 7, the trim cover 20 is formed in a ring shape. Specifically, the decorative cover 20 is arranged to extend in a horn shape from one end portion (floor-side end portion) to the other end portion (ceiling 4-side end portion) and cover the reflection cover 14 and the appliance main body 8 from the side. The decorative cover 20 is made of, for example, white polystyrene resin.

As shown in fig. 6 and 7, an annular support portion 20a extending while being bent toward the radial inner side of the trim cover 20 and the other end portion of the trim cover 20 is formed at one end portion of the trim cover 20. The support portion 20a supports an inner peripheral surface of a light guide portion 22b (described later) of the light guide plate 22.

An annular projection 20b extending over the entire circumference of the trim cover 20 is formed on the inner surface of the trim cover 20. The projection 20b contacts the flange 14b of the reflection cover 14. Accordingly, the trim cover 20 is positioned relative to the reflector 14.

[ 1-9. light guide plate ]

Next, the light guide plate 22 will be described with reference to fig. 1 to 7 and 10. Fig. 10 is a diagram illustrating the light guide plate 22 according to the embodiment. Fig. 10 (a) is a perspective view showing the light guide plate 22, and fig. 10 (b) is an X-X sectional perspective view of fig. 10 (a).

The light guide plate 22 is an optical member for guiding incident light from each of the plurality of second light emitting elements 46 in a predetermined direction (direction toward the space 6). As shown in fig. 1 to 7 and 10 (a), the light guide plate 22 is formed in a ring shape (annular shape) having a substantially circular opening 22a at the center thereof. The light guide plate 22 includes a light guide portion 22b, an incident portion 22c, an emitting portion 22d, and a plurality of branched light guide portions 22 e. The light guide plate 22 is made of a material having light transmittance (for example, a transparent acrylic resin).

A prism shape 60 (an example of a microstructure portion) in which a plurality of prisms having a fine conical concave shape are arranged in the circumferential direction is formed on a part or all of the surface on which the emission portion 22d is formed. The shape of the prism is not limited to the concave shape, and may be a convex shape. That is, the prism shape 60 is formed by a prism surface through which light is transmitted and reflected by at least one flat or curved surface of a concave or convex shape. The shape of the prism is not limited to a conical shape, and may be, for example, a quadrangular pyramid shape, or a shape having an asymmetric concave portion, such as a conical shape, a quadrangular pyramid shape, or a ring shape, in which a part of the inclined surface has a function of transmitting and reflecting light. In addition, when the prism is formed in a convex shape, the prism shape 60 may be a printed matter formed by a method such as screen printing using ink containing particles or pigments having scattering properties. Alternatively, the prism shape 60 may be a rough surface formed by embossing or the like. The prisms may be arranged at equal intervals along a specific direction, or may be arranged randomly. In addition, the surface on which the emitting portion 22d is formed does not need to have prisms disposed on the entire surface, and may have prisms disposed only in a part thereof.

As shown in fig. 6 and 7, the light guide portion 22b is formed between the incident portion 22c and the exit portion 22d, and extends in a horn shape from one end portion (end portion on the ceiling 4 side) to the other end portion (end portion on the floor side). That is, the opening 22a is formed radially inward of the light guide 22b, and the plurality of first light-emitting elements 44 and the lens cover 18 are disposed at positions facing the opening 22 a. The light guide portion 22b guides light from one end portion to the other end portion. The inner peripheral surface (concave surface) of the light guide 22b is supported by the support portion 20a of the decorative cover 20. The outer peripheral surface (convex surface) of light guide 22b is covered with a reflection portion 24a (described later) of reflection member 24. That is, the light guide portion 22b is sandwiched between the support portion 20a of the trim cover 20 and the reflection portion 24a of the reflection member 24.

The incident portion 22c is formed in a ring shape around one end portion of the light guide portion 22b, and extends from the one end portion of the light guide portion 22b substantially parallel to the central axis 58 (Z-axis direction) of the opening 22 a. The incident portion 22c is disposed at a position facing and close to the plurality of second light-emitting elements 46.

The emitting portion 22d extends annularly from the entire circumference of the other end portion of the light guide portion 22b to the outside in the radial direction of the light guide plate 22. The emitting portion 22d projects outward in the radial direction of the light guide plate 22 from the one end portion of the trim cover 20, and is disposed in a substantially horizontal posture (i.e., a posture substantially parallel to the ceiling 4). One surface (floor-side surface) of the emitting portion 22d is a surface from which light is emitted. As shown in fig. 7, the prism shape 60 is formed on the other surface (the surface on the ceiling 4 side) of the emitting portion 22 d.

As shown in fig. 5 to 7, the plurality of branched light guide portions 22e are branched and extended from the incident portion 22c toward the inside in the radial direction of the light guide plate 22 (i.e., in a direction different from the direction in which the light guide portions 22b extend). The plurality of branched light guide portions 22e are arranged at intervals in the circumferential direction of the incident portion 22c so as to correspond to the plurality of substrates 42. Each of the plurality of branched light guide portions 22e is attached to a predetermined region (a region between the plurality of first light emitting elements 44 and the plurality of second light emitting elements 46) of the corresponding substrate 42 by a screw 48 (see fig. 8).

Here, the characteristic structure of the light guide plate 22 will be described in more detail with reference to fig. 10 to 12. FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 10 (a). Fig. 12 is an enlarged cross-sectional perspective view illustrating the incident portion 22c of the light guide plate 22 according to the embodiment. In fig. 11, hatching indicating the cross section is omitted for convenience of explanation.

As shown in fig. 11 and 12, the incident portion 22c has a prism structure 62 that converts a part of the divergent light from the second light-emitting element 46 into light parallel to a predetermined direction. In a cross section (cross section shown in fig. 11 and 12) obtained by cutting light guide portion 22b along a virtual plane including central axis 58 of opening 22a, central axis 64 of prism structure 62 extends substantially parallel to the vertical direction (Z-axis direction).

As shown in fig. 12, the prism structure 62 is formed asymmetrically with respect to the central axis 64 in the cross section. That is, in the cross section, the curvature of the convex surface 62a of the prism structure 62 on one side of the central axis 64 is different from the curvature of the convex surface 62b of the prism structure 62 on the other side of the central axis 64.

As shown in fig. 11, light guide portion 22b has inclined portion 66 and bent portion 68.

As shown in fig. 11 and 12, the inclined portion 66 extends obliquely from the incident portion 22c toward the exit portion 22d with respect to the central axis 64 of the prism structure 62. The inclination angle θ with respect to the central axis 64 of the inclined portion 66 is, for example, about 10 °.

As shown in fig. 11, the curved portion 68 extends from the inclined portion 66 to the exit portion 22 d. A first reflecting surface 70, a second reflecting surface 72, and a third reflecting surface 74 for reflecting and guiding the light incident on the incident portion 22c toward the emitting portion 22d are formed on the outer peripheral surface (convex surface) of the curved portion 68.

The first reflecting surface 70 forms a parabola having a focal point F in the cross section. First reflecting surface 70 is formed in a range from the boundary position between curved portion 68 and inclined portion 66 to a position closer to incident portion 22c than focal point F.

The second reflecting surface 72 forms a curve such as a parabola or a circular arc in the cross section. The second reflecting surface 72 is formed in a range from a boundary position between the curved portion 68 and the emitting portion 22d to a position closer to the emitting portion 22d than the focal point F. That is, the second reflecting surface 72 is disposed on the side closer to the exit portion 22d than the first reflecting surface 70 is in the cross section.

More specifically, the second reflecting surface 72 is disposed at a position intersecting a virtual straight line (shown by a chain line in fig. 11) passing through the first reflecting surface 70 and the focal point F in the cross section. In other words, the second reflecting surface 72 is formed in a region sandwiched by a virtual straight line 76 passing through one end of the first reflecting surface 70 on the incident portion 22c side and the focal point F, and a virtual straight line 78 passing through the other end of the first reflecting surface 70 on the exit portion 22d side and the focal point F, in the cross section.

As shown in fig. 10 (a) and (b), a rough surface 80 is formed on the convex surface side of the second reflecting surface 72 by embossing. In this case, the rough surface 80 may be formed on the entire area of the second reflection surface 72, or may be formed only on a part of the second reflection surface 72. Instead of the above-described embossing, the second reflective surface 72 may be subjected to a random roughening process such as embossing or sandblasting to form the rough surface 80.

The third reflecting surface 74 forms a curve such as a parabola or a circular arc in the cross section. The third reflecting surface 74 is formed between the first reflecting surface 70 and the second reflecting surface 72. The first reflecting surface 70, the second reflecting surface 72, and the third reflecting surface 74 are formed to be smooth curves as a whole in the cross section.

As shown in fig. 11, a recess 82 is formed between light guide unit 22b and light emitting unit 22d on the inner peripheral surface side of light guide unit 22 b. Recess 82 is formed in a ring shape around the other end of light guide 22 b. The thickness (the size in the Z-axis direction) of the region of the injection portion 22d where the recess 82 is formed is smaller than the thickness of the region of the injection portion 22d where the recess 82 is not formed.

[ 1-10. reflecting Member ]

Next, the reflecting member 24 will be described with reference to fig. 4 to 7. The reflecting member 24 is a member for reflecting the light guided inside the light guide portion 22b of the light guide plate 22.

As shown in fig. 4 to 7, the reflecting member 24 is formed in a ring shape. Specifically, the reflecting member 24 includes a reflecting portion 24a and a pressing portion 24 b. Further, the reflecting member 24 is formed of, for example, polycarbonate resin or the like.

The reflection portion 24a extends in a horn shape from one end (end on the ceiling 4 side) to the other end (end on the floor side). A reflection surface is formed on the concave surface side of the reflection portion 24 a. The concave side of the reflection portion 24a covers the outer peripheral surface of the light guide portion 22b of the light guide plate 22.

The pressing portion 24b extends annularly from the entire circumference of one end portion of the reflecting portion 24a radially inward of the reflecting member 24. Pressing portion 24b is attached to a predetermined region of each of the plurality of substrates 42 together with the plurality of branched light guide portions 22e by screws 48. Accordingly, as shown in fig. 6 and 7, the distal end portion of the pressing portion 24b presses the outer peripheral portion of the lens cover 18 against the plurality of substrates 42.

[ 1-11. diffusion cover ]

Next, the diffusion cover 26 will be described with reference to fig. 1 and 3 to 7. The diffusion cover 26 is a cover for diffusing light from each of the plurality of first light-emitting elements 44.

As shown in fig. 1 and 3 to 7, the diffusion cover 26 is detachably attached to the reflection member 24 and is disposed so as to cover the opening 22a of the light guide plate 22. As shown in fig. 3, the lens cover 18 is exposed from the opening 22a of the light guide plate 22 by removing the diffusion cover 26 from the reflecting member 24. As shown in fig. 6 and 7, the diffusion cover 26 includes a diffusion portion 26a and a mounting portion 26 b.

The diffusion portion 26a is formed in a disc shape and is arranged to cover the opening 22a of the light guide plate 22. The diffuser 26a is formed of a material having light transmittance (for example, milky acrylic resin).

The mounting portion 26b extends in a trumpet shape from the entire circumference of the outer circumferential portion of the diffuser portion 26a toward the axial direction (Z-axis direction) of the diffuser portion 26 a. The mounting portion 26b is detachably mounted on the convex surface side of the reflection portion 24a of the reflection member 24.

[ 1-12. illumination method ]

Next, a method of lighting the lighting fixture 2 will be described with reference to fig. 6, 7, and 11. The direct current from the power supply unit 12 is supplied to the light emitting module 16, so that each of the plurality of first light emitting elements 44 and the plurality of second light emitting elements 46 emits light.

As shown in fig. 6 and 7, the light from each of the plurality of first light-emitting elements 44 passes through the corresponding lens portion 18a of the lens cover 18, and then enters the diffusion cover 26 through the opening 22a of the light guide plate 22. The light incident on the diffusion cover 26 is diffused and emitted from the diffusion cover 26, and then is irradiated to the space 6. That is, the light from each of the plurality of first light emitting elements 44 is directly irradiated to the space 6 without being incident on the light guide plate 22.

As shown in fig. 7, a part of the light from each of the plurality of first light-emitting elements 44 is reflected by the reflecting member 24 or the like and then reflected by one surface of the reflection cover 14. The light thus multiply reflected is incident on the diffusion cover 26. Accordingly, the light extraction efficiency can be improved.

On the other hand, as shown in fig. 7 and 11, when light (divergent light) from each of the plurality of second light-emitting elements 46 enters the entrance portion 22c of the light guide plate 22, a part of the light is converted into light parallel to the light guiding direction by the prism structure 62. The parallel light entering the incident portion 22c is guided from the incident portion 22c to the emission portion 22d while being reflected by the first reflection surface 70, the second reflection surface 72, and the third reflection surface 74 inside the light guide portion 22b (and while being reflected by the reflection portion 24a of the reflection member 24).

As shown in fig. 11, the light guided into the light guide portion 22b is first incident on the concave side of the first reflection surface 70 at an incident angle larger than the critical angle, and is totally reflected by the first reflection surface 70. At this time, it is preferable that the first reflecting surface 70 be disposed in a region where most of the parallel light incident on the incident portion 22c can be totally reflected. The light totally reflected by the first reflecting surface 70 converges and travels toward the focal point F inside the light guide unit 22b, is condensed at the focal point F, is then diverged, and is incident on the second reflecting surface 72.

The light from the first reflecting surface 70 is incident on the concave side of the second reflecting surface 72 at an incident angle larger than the critical angle, and is totally reflected by the second reflecting surface 72. The light totally reflected by the second reflecting surface 72 is guided inside the emitting portion 22d, reflected by the prism shape 60 formed on the other surface of the emitting portion 22d, and emitted from one surface of the emitting portion 22 d.

At this time, the light from the second light emitting element 46 is converted into parallel light by the prism structure 62, and then condensed at the focal point F by the parabolic characteristic of the first reflecting surface 70. Therefore, if the convex surface side of the second reflecting surface 72 is a smooth surface, the light totally reflected by the second reflecting surface 72 is guided into the emitting portion 22d in a condensed light beam state, and therefore, a streak is generated in one surface of the emitting portion 22d due to the density distribution of the condensed light beam. In contrast, in the present embodiment, since the rough surface 80 is formed on the second reflecting surface 72, the light totally reflected by the second reflecting surface 72 is diffused and guided into the emitting portion 22 d. This can suppress the occurrence of the streak on the surface on one side of the emitting portion 22 d.

Part of the light guided into light guide unit 22b is reflected by the concave surface of third reflecting surface 74, and then guided into light emitting unit 22 d.

Then, a part of the light (return light) reflected by the prism shape 60 a plurality of times travels in a direction to return to the light guide section 22 b. However, as shown in fig. 11, the return light is reflected by the concave portion 82 formed in the light guide plate 22, and is guided again into the emitting portion 22d without returning to the light guide portion 22 b.

As shown in fig. 11, a part of the light that is not converted into parallel light by the prism structure 62, out of the light incident on the incident portion 22c of the light guide plate 22, enters the branched light guide portion 22 e. At this time, pressing portion 24b of reflecting member 24 is made of, for example, a transparent resin, and thus, light incident on branched light guide portion 22e is transmitted through pressing portion 24b and enters diffusion cover 26. Alternatively, the pressing portions 24b of the reflecting member 24 may be omitted, and the light incident on the branched light guide portions 22e may be incident on the diffusion cover 26. Further, when the second reflecting surface 72 is subjected to surface roughening treatment such as embossing, part of the guided light can be made incident on the diffusion cover 26, and the diffusion cover 26 can uniformly emit light when emitting light, so that the quality of the appearance of the illumination can be improved.

As described above, the space 6 can be directly illuminated by the light from the diffusion cover 26, and the space 6 can be illuminated by the light guided from the light emitting portion 22d of the light guide plate 22. Accordingly, the space 6 directly below the lighting device 2 is illuminated with light from the diffuser cover 26 relatively brightly, and thus, for example, a required illuminance for reading or manual work can be ensured. On the other hand, since the space 6 around the lighting fixture 2 is relatively darkly illuminated by the light from the light emitting portion 22d of the light guide plate 22, as in indirect illumination, a sense of comfort can be achieved.

In the present embodiment, the case where the plurality of first light-emitting elements 44 and the plurality of second light-emitting elements 46 are lit together has been described, but depending on, for example, the atmosphere in a room, only the plurality of first light-emitting elements 44 may be lit, or only the plurality of second light-emitting elements 46 may be lit.

[2. Effect ]

The lighting apparatus 2 of the present embodiment includes: a second light emitting element 46; and a light guide plate 22 for guiding light from the second light emitting element 46 in a predetermined direction. The light guide plate 22 includes: an incident portion 22c on which light from the second light emitting element 46 is incident; an exit portion 22d that exits the light incident on the entrance portion 22 c; and a light guide portion 22b that is formed between the incident portion 22c and the exit portion 22d, extends from the incident portion 22c to the exit portion 22d while being curved, and has a first reflection surface 70 and a second reflection surface 72 on an outer peripheral surface thereof for reflecting light incident on the incident portion 22c and guiding the light to the exit portion 22 d. First reflecting surface 70 forms a parabola having focal point F in a cross section when light guide portion 22b is cut off in a virtual plane. The second reflecting surface 72 is disposed on the side closer to the exit portion 22d than the first reflecting surface 70 in cross section, and is disposed at a position intersecting a virtual straight line passing through the first reflecting surface 70 and the focal point F.

Accordingly, the first reflecting surface 70 forms a parabola having the focal point F in the cross section, and therefore, among the light guided to the inside of the light guide part 22b, the light reflected at the first reflecting surface 70 converges and travels toward the focal point F inside the light guide part 22b, is condensed at the focal point F, and then diverges and is incident on the second reflecting surface 72. The light reflected by the second reflecting surface 72 is guided inside the emitting portion 22d and emitted from the emitting portion 22d to the space 6. Accordingly, since the light reflected by the first reflecting surface 70 can be efficiently incident on the second reflecting surface 72, the occurrence of propagation loss of the light in the light guide portion 22b can be suppressed, and the utilization efficiency of the light from the second light emitting element 46 can be improved.

Further, the incident portion 22c has a prism structure 62 that converts a part of the light from the second light emitting element 46 into light parallel to the light guiding direction.

Accordingly, the light from the second light emitting element 46 can be efficiently reflected by the first reflecting surface 70, and therefore the utilization efficiency of the light from the second light emitting element 46 can be further improved.

Further, the prism structure 62 is formed to be asymmetrical with respect to a central axis 64 of the prism structure 62 in cross section.

Accordingly, the optical axis of the parallel light flux from the prism structure 62 is inclined with respect to the central axis 64 of the prism structure 62, and therefore, the parallel light flux from the prism structure 62 can be made incident on the first reflection surface 70 at an incident angle larger than the critical angle. As a result, the light incident on the first reflecting surface 70 is totally reflected by the first reflecting surface 70, and therefore the utilization efficiency of the light from the second light emitting element 46 can be further improved.

Light guide 22b further includes: an inclined portion 66 extending from the incident portion 22c in a direction approaching the emission portion 22d with respect to the central axis 64 of the prism structure 62; and a curved portion 68 curved and extended from the inclined portion 66 to the exit portion 22d, and formed with a first reflection surface 70 and a second reflection surface 72.

This enables the parallel light flux from the prism structure 62 to be efficiently guided into the inclined portion 66.

Further, a rough surface 80 is formed on at least a part of the second reflection surface 72.

Accordingly, the light reflected by the second reflecting surface 72 is diffused by the rough surface 80 and guided to the inside of the emitting portion 22 d. This can suppress the occurrence of streaks in the emission portion 22d due to the density distribution of the condensed light flux.

Further, the second reflecting surface 72 forms a curve in the cross section.

Accordingly, the light reflected by the second reflecting surface 72 can be efficiently guided to the inside of the emitting portion 22 d.

Further, a recess 82 is formed between light guide unit 22b and light emitting unit 22d on the inner peripheral surface side of light guide unit 22 b.

Accordingly, the return light that has traveled from the light emitting portion 22d in the direction of returning to the light guide portion 22b is reflected by the concave portion 82, and is guided again into the light emitting portion 22d without returning to the light guide portion 22 b. As a result, the efficiency of using light from the second light-emitting element 46 can be further improved.

Further, the light guide plate 22 includes a branched light guide portion 22e branched and extended from the incident portion 22c in a direction different from the light guide portion 22 b.

Accordingly, among the light incident on the light incident portion 22c, the light not guided to the inside of the light guide portion 22b can be made incident on the branched light guide portion 22 e. As a result, the light entering branched light guide part 22e can contribute to direct illumination of space 6, and the utilization efficiency of the light from second light-emitting element 46 can be further improved.

Further, at least a part of the emitting portion 22d is formed with a prism shape 60 for emitting light from the emitting portion 22 d.

Accordingly, the light guided to the inside of the emitting portion 22d is reflected by the prism shape 60 and emitted from the emitting portion 22 d. As a result, light can be efficiently emitted from the emitting portion 22 d.

Further, the light guide plate 22 is formed in a ring shape having an opening 22 a. Light guide 22b has opening 22a, and is flared from incident portion 22c to exit portion 22 d. The incident portion 22c extends from one end of the light guide portion 22b substantially parallel to the central axis 58 of the opening 22 a. The light emitting portion 22d extends from the other end portion of the light guide portion 22b to the outside in the radial direction of the light guide portion 22 b. The virtual plane is a plane including the central axis 58 of the opening 22 a.

Accordingly, the light guide plate 22 is formed in a ring shape, and the lighting fixture 2 can be applied to, for example, a circular ceiling lamp.

(modification example)

Next, a light guide plate 22A according to a modification of the embodiment will be described with reference to fig. 13. Fig. 13 is an enlarged perspective view showing a part of the light guide plate 22A according to a modification of the embodiment.

As shown in fig. 13, a rough surface 80A is formed in the prism shape on the second reflection surface 72A of the light guide plate 22A according to the modification. With such a configuration, as in the above-described embodiment, it is possible to suppress occurrence of streaks due to the density distribution of the light flux condensed at the emitting portion 22 d.

Instead of the prism shape, the second reflecting surface 72A may be formed with a microlens array shape, for example, to form the rough surface 80A.

(other modifications, etc.)

The present invention has been described above based on the embodiments and the modifications, but the present invention is not limited to the embodiments and the modifications.

In the above embodiment, the lighting fixture 2 is a ceiling lamp, but is not limited to this, and may be, for example, a ceiling lamp, a pendant lamp, a wall lamp, a bathroom lamp, a kitchen lamp, or the like. Alternatively, the lighting fixture 2 may be, for example, a backlight mounted on a liquid crystal display.

In the above-described embodiment and the like, the prism structure is the prism structure 62 that converts the divergent light from the second light-emitting element 46 into the parallel light, but the present invention is not limited to this, and may be a condenser lens structure that converts the divergent light from the second light-emitting element 46 into the convergent light, for example.

In the above-described embodiment and the like, the light guide plate 22(22A) is formed in a ring shape, but the present invention is not limited thereto, and may be formed in a rectangular shape, for example.

In the above embodiment and the like, the second reflecting surface 72 is formed in a curved line in the cross section, but the present invention is not limited thereto, and the second reflecting surface 72 may be formed in a straight line in the cross section, for example.

In the above-described embodiment and the like, the mounting structures of the first light-emitting element 44 and the second light-emitting element 46 are SMD structures, but the SMD structures are not limited to this, and may be cob (chip On board) structures in which LED chips are directly mounted On the substrate 42, for example. In this case, the plurality of LED chips mounted on the substrate 42 may be collectively sealed by the sealing member, or may be individually sealed. The sealing member may contain a wavelength conversion material such as the yellow phosphor.

In the above-described embodiments and the like, the LEDs are exemplified as the first light emitting element 44 and the second light emitting element 46, but the present invention is not limited thereto, and for example, a semiconductor light emitting element such as a semiconductor laser, or other solid state light emitting element such as an organic EL (electro luminescence) or an inorganic EL may be used.

In addition, the present invention includes an embodiment obtained by applying various modifications that will occur to those skilled in the art to the above-described embodiments and the like, and an embodiment in which the constituent elements and functions of the respective embodiments are arbitrarily combined and realized within a scope not departing from the gist of the present invention.

Claims (10)

1. A lighting fixture is provided with:

a light emitting element; and

a light guide plate for guiding light from the light emitting element in a predetermined direction,

the light guide plate has:

an incident portion on which light from the light emitting element is incident;

an exit portion that exits light incident on the incident portion; and

a light guide portion formed between the incident portion and the emission portion, and extending from the incident portion to the emission portion in a curved manner, the light guide portion having a first reflection surface and a second reflection surface on an outer peripheral surface thereof for reflecting and guiding light incident on the incident portion toward the emission portion,

the first reflecting surface forms a parabola having a focal point on a cross section obtained when the light guide part is cut by a virtual plane,

the second reflecting surface is disposed on the side closer to the emission portion than the first reflecting surface in the cross section and is disposed at a position intersecting a virtual straight line passing through the first reflecting surface and the focal point,

the light reflected by the first reflecting surface among the light guided into the light guide unit travels inside the light guide unit while converging toward the focal point, and is reflected by the second reflecting surface while diverging after converging at the focal point,

the light reflected by the second reflecting surface is guided inside the emitting portion and emitted from the emitting portion.

2. The lighting fixture of claim 1,

the incident portion has a prism structure that converts light from the light emitting element into parallel light or convergent light.

3. The lighting fixture of claim 2,

the prism structure is formed asymmetrically with respect to a central axis of the prism structure in the cross section.

4. The lighting fixture of claim 3,

the light guide part includes:

an inclined portion extending obliquely from the incident portion in a direction approaching the exit portion with respect to a central axis of the prism structure; and

and a curved portion extending from the inclined portion to the emission portion, and having the first reflection surface and the second reflection surface formed thereon.

5. The lighting fixture of claim 1,

a rough surface is formed on at least a part of the second reflecting surface.

6. The lighting fixture of claim 1,

the second reflecting surface forms a curve on the cross section.

7. The lighting fixture of claim 1,

a recess is formed between the light guide portion and the light emitting portion on the inner peripheral surface side of the light guide portion.

8. The lighting fixture of claim 1,

the light guide plate further includes a branched light guide portion branched and extended from the incident portion in a direction different from the light guide portion.

9. The lighting fixture of claim 1,

at least a part of the emission part is formed with a microstructure part for emitting light from the emission part.

10. The lighting fixture of any of claims 1-9,

the light guide plate is formed in a ring shape having an opening portion,

the light guide portion has the opening portion, and is expanded in a horn shape from the incident portion toward the emission portion,

the incident portion extends from one end portion of the light guide portion substantially parallel to a central axis of the opening portion,

the light emitting portion extends from the other end portion of the light guide portion to the outside in the radial direction of the light guide portion,

the virtual plane is a plane including the central axis of the opening.

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