JP2013069430A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device capable of irradiating light to a side face or in a back direction and reducing luminance unevenness.SOLUTION: The lighting device includes a base material 2, a light source 6 arranged on a front section of the base material, and a light guide 7 arranged by facing to the light source and guiding at least a part of light emitted ahead from the light source in a back direction or in a side face direction of the light source. The light guide 7 is formed in a rotational symmetrical shape around the center axis, and has at least first light guide sections 7a and second light guide sections 7b wherein they are respectively different on optical characteristics. The first light guide sections and the second light guide sections are respectively arranged by periodically lining up in a circumferential direction of the center axis.

Description

  Embodiments described herein relate generally to a lighting device using a light source and a light source with narrow directivity such as a white light emitting diode (LED).

Incandescent light bulbs that use light emission by the heat of filaments have been widely used as lighting devices, but have problems such as short life and luminous efficiency.
In recent years, as a technique for solving these problems, LED light sources and EL (electroluminescence) light sources have been developed, and in particular, the use of LED light sources for general lighting devices is accelerating.

  In general, an LED light bulb has a base composed of a base mounted on a metal base material and a hemispherical light-transmitting cover, and an LED light source mounted at a position corresponding to the center of the light-transmitting cover. It is attached to. The light source emits light via the drive circuit built in the base material by the electric power supplied from the base.

  Since a light source mounted on a planar mounting substrate such as an LED light source emits light strongly in the normal direction of the mounting substrate, the light distribution tends to be biased as a lighting device. This is because the structure of the LED light source is such that the LED chip that emits the primary light is formed in a planar shape on the mounting substrate with a protective layer containing a phosphor that converts the primary light to the secondary light. For this reason, the light emitted from the LED light source is affected by scattering by the phosphor, and the luminous intensity changes according to cos θ when the angle formed with the normal direction of the mounting substrate is θ, and from the side of the mounting substrate toward the back side There is almost no light until.

  As a technique for solving the problem of this narrow light distribution, a technique has been proposed in which the LEDs constituting the light source are three-dimensionally arranged with their side surfaces and back directions directed. As another technique, there is a technique in which a phosphor that is excited by light from an LED light source is applied to the inner surface of a light-transmitting cover so that the light-transmitting cover itself shines. As another technique, a technique of arranging a light source at the lower end of a spherical translucent cover has been proposed. As another technique, there is a technique of installing a light guide near the LED light source.

Japanese Patent No. 4076329 Japanese Patent No. 4290887 JP 2010-27282 A Japanese Patent Laid-Open No. 2005-5546 Japanese Patent No. 4135485 JP 2004-342411 A JP 2009-289697 A JP 2010-40364 A JP 2011-14515 A Japanese Patent Laid-Open No. 10-21710 JP 2006-190684 A JP 2007-194132 A JP 2010-15754 A

  When the LED light source is three-dimensionally mounted, there is a problem that the manufacturing and assembly of the lighting device becomes complicated and the design difficulty of mechanical strength and heat dissipation increases. In addition, when the phosphor is applied to the light-transmitting cover, there is a problem that the manufacturing and assembling of the lighting device becomes complicated. When the light source is arranged at the lower end of the spherical light-transmitting cover, the base material is shortened due to the length restriction of the entire lighting device, and the heat radiation is deteriorated, so that a large amount of light cannot be obtained. In addition, when the light guide is installed, the conventional technology cannot provide a sufficient light distribution control function and a natural design.

  The present invention has been made in view of the above points, and an object thereof is to provide an illumination device that can irradiate light to the side surface or the back surface direction and can reduce luminance unevenness.

According to the embodiment, the lighting device is provided with a base material, a light source disposed on a front surface portion of the base material, and opposed to the light source, and at least a part of light emitted forward from the light source. A light guide that guides light in a back direction or a side direction of the light source,
The light guide is formed in a rotationally symmetric shape with respect to a central axis, and includes at least a first light guide part and a second light guide part having different optical characteristics, and the first light guide part and the first light guide part Two light guide portions are periodically arranged in the circumferential direction of the central axis.

FIG. 1 is a cross-sectional view showing a light bulb-type lighting device according to a first embodiment. FIG. 2 is a plan view showing a light source arrangement of the illumination device. FIG. 3 is a plan view showing a light guide in the illumination device. FIG. 4 is a diagram illustrating a luminance distribution on a light-transmitting cover of the lighting device. FIG. 5 is a cross-sectional view showing a light bulb-type lighting device according to a second embodiment. FIG. 6 is a plan view showing a relative position between the light source and the light guide of the lighting apparatus according to the second embodiment. FIG. 7 is a plan view showing another relative position between the light source and the light guide of the illumination device according to the second embodiment. FIG. 8 is a cross-sectional view showing a light bulb-type lighting device according to a third embodiment. FIG. 9 is a plan view showing the positional relationship between the light guide and the heat radiating fins in the lighting apparatus according to the third embodiment.

Hereinafter, illumination devices according to various embodiments will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view of an LED bulb 1 as a bulb-type illumination device according to the first embodiment, and FIGS. 2 and 3 are plan views showing a light source array and a light guide body of the LED bulb 1, respectively.
As shown in FIG. 1, the LED bulb 1 includes a base material 2, a light source 6 made of LEDs, a substantially spherical translucent cover 4, a base 3, and a light guide 7 disposed on the light source 6. Each member is configured to be rotationally symmetric with respect to the central axis C.

  The base material 2 is a metal housing and a heat dissipation member, the upper part is formed in a substantially truncated cone shape, has a flat front part at the upper end, and the lower part is formed in a substantially cylindrical shape, and the lower end thereof A base 3 is attached to the base. A drive circuit 12 that drives the light source 6 is housed inside the base material 2. The surface of the base material 2 is coated with white so that the reflectance is higher than that of other parts, so that light that is reflected and scattered inside the translucent cover 4 is less likely to be absorbed and lost to the air efficiently. Dissipates heat.

  The upper part of the base material 2 protrudes greatly to the center of the sphere of the translucent cover 4. As shown in FIGS. 1 and 2, a mounting substrate 5 is installed on the flat front portion at the top, and a plurality of light sources 6 are installed on the substrate 5, and in a circle shape concentric with the central axis C. It is arranged. Each light source 6 includes, for example, an LED chip and a sealing resin that covers the LED chip, and phosphor particles that convert primary light from the LED chip into white light are dispersed and mixed in the sealing resin. Yes. The electric power supplied from the base 3 is supplied to the light source 6 through the drive circuit 12, and the light source 6 emits white light. This white light emits light with a strong luminous intensity in the normal direction of the mounting substrate 5, that is, in the forward direction of the LED bulb 1.

  As shown in FIG. 1, in the present embodiment, the translucent cover 4 is formed of a milky white member in a substantially spherical shape, and is fixed and supported on the upper portion of the base material 2 with its center substantially coincident with the light source 6. . Thereby, the translucent cover 4 covers the front surface, the side surface, and the back surface side of the light source 6 and covers the upper outer periphery of the substrate 2. And the translucent cover 4 has the front side translucent area | region where the surface normal direction faced the front side of the LED bulb 1, and the back side translucent area | region 4a which faced the back side.

  As shown in FIGS. 1 and 3, the light guide 7 is disposed in front of the light source 6 in the translucent cover 4 and supported by the front surface portion of the substrate 2. The light guide body 7 is formed in a seagull cross section, is coaxial with the central axis C of the lighting device 1, and is formed into a shape to be rotated with respect to the central axis C. The light guide body 7 includes a plurality of at least two types of first and second light guide body portions 7a and 7b having different optical characteristics, and the first light guide body portion 7a and the second light guide body portion 7b are the center. They are periodically arranged in the circumferential direction of the axis C. The first and second light guide portions 7a and 7b have different cross-sectional shapes parallel to the central axis C. In the circumferential direction around the central axis C, for example, first light guide body portions 7a and second light guide body portions 7b having two types of cross-sectional shapes are arranged alternately at intervals of 15 degrees.

  Each first light guide portion 7a includes a light incident portion 8a that faces the light source 6, and a light emitting portion that extends curvedly outward from the light incident portion and extends along the side and back sides of the light source. And a light guide / emission unit 9a that guides light incident on the light incident unit in a curved manner and emits the light from the light exit unit.

  Similarly, each of the second light guide portions 7b extends from the light incident portion 8b facing the light source 6 and curved outward from the light incident portion and along the side surface and back side of the light source. It has a light emitting part 10b, and has a light guide emitting part 9b that guides light incident on the light incident part in a curved manner and emits it from the light emitting part. The light emitting part 10b of the second light guide part and the light emitting part 10a of the first light guide part are different from each other in the arrangement height and the light emitting direction along the axial direction of the central axis C. The light guide 7 is an integrally molded product formed by injection molding, for example, and the first and second light guide portions 7a and 7b are integrally formed.

  As described above, the first and second light guide portions 7 a and 7 b of the light guide 7 include the light emitting portions 10 a and 10 b that emit light toward the side surface and the back surface of the light source 6, and the back surface of the translucent cover 4. The back side translucent area | region 4a which faced the side is irradiated with light, and the back side illumination intensity of the LED bulb 1 is ensured. Further, the front side of the LED bulb 1 is irradiated by a concave lens portion 22 formed inside the central portion of the light guide 7 so that a part of the light irradiated mainly inward of the light source 6 is widened to the front side. It is ensured by diffusing irradiation. Thereby, the LED bulb 1 having a light distribution equivalent to that of the incandescent bulb is obtained.

FIG. 4 is a diagram for explaining luminance unevenness mitigation from the upper end vertex A to the rear side end B of the translucent cover 4.
According to the LED light bulb 1 according to the present embodiment, the specifications of the light emitting portions 10a and 10b of the first and second light guide portions 7a and 7b of the light guide 7 are different and dispersed for each angle around the central axis. Therefore, it can be set as the structure which does not produce the brightness nonuniformity on the translucent cover 4 easily. In FIG. 4, the brightness distribution of the light-transmitting cover by the light guide 7 of the present embodiment, the brightness distribution of the light-transmitting cover when the light guide is entirely formed by the first light guide body portion 7a, and the guide The luminance distribution of the translucent cover when the light bodies are all formed only by the first light guide portion 7a is shown. In the case of only the first light guide portion 7a and the case of only the second light guide portion 7b, a strong luminance peak is generated in the vicinity of the light emitting portions 10a and 10b. On the other hand, in the LED bulb 1 according to the present embodiment, it can be seen that the luminance distribution is an averaged luminance distribution of these luminance peaks, and luminance unevenness is reduced.

  From the above, according to the first embodiment, it is an object to provide a light bulb-type lighting device that can irradiate light to the side surface or the back surface direction and can reduce luminance unevenness.

  In the above-described first embodiment, the plurality of light sources 6 are arranged in a circle, but the light source specifications may be arranged in the center. The cross-sectional shape of the light guide is not limited to two types, and three or more types may be combined.

  The angle range in which the same cross-sectional shape of the light guide 7 continues is not limited to 15 degrees, and can be increased / decreased within a range in which the luminance unevenness in the circumferential direction does not occur. Good. In this embodiment, the light guide is formed with two types of cross sections having different shapes. However, the light emitting portion may be formed of a texture or a groove. In this case, the shape is the same and the position of the texture is in the circumferential direction. You may make it differ by an angle.

  In the present embodiment, a light guide having a light incident portion covering the light source is used for the LED light sources gathered into one, but the light source may be a plurality of LED light sources dispersedly arranged. It is good also as a light guide which makes light enter with respect to a LED light source.

  Next, a lighting device according to another embodiment will be described. In other embodiments to be described later, the same parts as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

(Second Embodiment)
FIG. 5 is a cross-sectional view showing the LED bulb 1 according to the second embodiment, and FIGS. 6 and 7 are plan views of the light guide moved to different phase positions. The basic configuration of the LED bulb 1 excluding the light guide 7 is the same as that of the first embodiment described above.

  As shown in FIGS. 5 to 7, according to the second embodiment, one of the two types of the first light guide body portion 7a and the second light guide body portion 7b constituting the light guide body 7 is guided. The light body portion, for example, the first light guide body portion 7a is formed of an air layer. The plurality of light sources 6 and the second light guide body portion 2b of the light guide body 7 are arranged in a synchronized manner in the circumferential direction around the central axis. Thereby, by adjusting and arranging the phase of the light guide body 7 in the circumferential direction, it is possible to select whether the light guide function of the light guide body 7 is exhibited or not.

  For example, as shown in FIG. 6, when the light source 6 and the second light guide body portion 7 b of the light guide body 7 are aligned with each other, the light emitted from the light source 6 is transmitted by the light guide body 7 to the LED bulb 1. It becomes possible to irradiate the back side, and the LED bulb 1 that irradiates in all directions can be configured as in the first embodiment.

  On the other hand, as shown in FIG. 7, when the light source 6 and the second light guide 7 b of the light guide 7 are shifted in the circumferential direction, mainly the front side is mainly obeyed by the original light distribution of the LED light source 6. The LED bulb 1 to be irradiated is configured.

  In the light guide 7 of the second embodiment, a front condensing type light guide may be installed instead of the air layer, and in this case, in a narrow range far from the front such as a flashlight or a spotlight. It is possible to switch completely different irradiation characteristics such as a mode for realizing high illuminance and a mode for irradiating the whole.

(Third embodiment)
FIG. 8 is a cross-sectional view showing the LED bulb 1 according to the third embodiment, and FIG. 9 is a plan view showing the positional relationship between the light guide of the LED bulb and the radiation fin. The basic configuration of the LED bulb 1 is the same as that of the first embodiment.

  In the third embodiment, a plurality of radiating fins 11 extending radially are provided on the outer periphery of the base material 2. Each radiating fin 11 is opposed to the rear surface side translucent region 4 a of the translucent cover 4 and extends to the maximum diameter portion of the translucent cover 4. The heat radiating fins 11 are formed in a plate shape parallel to the central axis of the LED bulb 1 so as not to obstruct light in the back direction of the light source 6. The plurality of radiating fins 11 are arranged at equal intervals in the circumferential direction of the substrate 2.

  The light guide 7 is spaced apart from each other along the circumferential direction of the central axis, and has a plurality of wedge-shaped cuts 13 that taper toward the central axis, and each cut is formed of an air layer. One light guide portion is formed. Thereby, the 2nd light guide part 7b of the light guide 7 is located in a line at equal intervals in the circumferential direction.

  Each second light guide portion 7b includes a light incident portion 8 that faces the light source 6, and a light emitting portion that extends curvedly outward from the light incident portion and extends along the side surface and the back side of the light source. And a light guide / emission part 9 that guides light incident on the light incident part in a curved manner and emits it from the light emitting part.

  The second light guide body portion 7 b of the light guide body 7 irradiates light to the back side light transmissive region 4 a facing the back side of the light transmissive cover 4 to ensure the back side illumination of the LED bulb 1. Irradiation to the front side of the LED bulb 1 is performed by diffusely irradiating a part of the light emitted mainly inward of the light source 6 toward the front side by the concave lens portion 22 formed inside the central portion of the light guide 7. It is secured by doing.

  The light guide 7 is disposed such that the plurality of cuts 13 and the heat radiating fins 11 are aligned along a direction parallel to the central axis.

  By providing a plurality of wedge-shaped cuts 13 in the light emitting part of the light guide 7, the light reflected and propagated in the circumferential direction of the light guide 7 exceeds the critical angle at the cuts 13 and a wide range of the cuts 13. Then, light is emitted in the convex direction of the cut 13. Thereby, the brightness nonuniformity of the translucent cover 4 can be relieved.

  Further, since the emitted light is condensed in the convex direction of the cut, the phase and the phase structure of the cut 13 are matched so as to avoid the light absorbers periodically arranged in the circumferential direction like the radiating fins 11. The efficiency can be improved by arranging the light guide 7.

  Also in the second and third embodiments configured as described above, light is irradiated to the side surface or the back surface direction by using a light guide body in which different cross-sectional shapes or light extraction textures are arranged in the circumferential direction. In addition, it is possible to obtain an illumination device that can reduce luminance unevenness.

The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
For example, although the light extraction structure from the light guide is not specifically mentioned, the light extraction structure may be provided by joining a texture or a diffusion member, or some scattering filler is mixed in the material constituting the light guide itself. Then, it may be scattered and taken out. The number and type of light sources are not particularly specified, and the action of the present invention can be applied to any light source having strong directivity in the front. Also, the light guide is fixed to the base material in the embodiment, but may be fixed to the light-transmitting cover.

  In addition, although the embodiment has been described as an LED bulb, any combination of a directional light source and a translucent cover that surrounds the light source in a substantially spherical shape can be applied to street lamp illumination or may be used as an EL light source. . Furthermore, it is also possible to omit the translucent cover and expose the light guide.

DESCRIPTION OF SYMBOLS 1 ... LED bulb, 2 ... Base material, 2a ... Upper part, 2b ... Lower part, 3 ... Base, 4 ... Translucent cover,
4a ... front side translucent region, 4b ... back side translucent region, 5 ... mounting substrate, 6 ... light source,
7 ... light guide, 7a ... light incident part, 7b ... light guide emitting part, 7c ... second light guide emitting part,
7d: Light emitting part

Claims (9)

A base material; a light source disposed on a front surface of the base material; and a light source disposed opposite to the light source, wherein at least part of light emitted forward from the light source is guided in a back direction or a side direction of the light source. A light guide that emits light,
The light guide is formed in a rotationally symmetric shape with respect to a central axis, and includes at least a first light guide part and a second light guide part having different optical characteristics, and the first light guide part and the first light guide part 2 An illuminating device in which light guide portions are periodically arranged in the circumferential direction of the central axis.   The lighting device according to claim 1, wherein the first and second light guide portions have different cross-sectional shapes parallel to the central axis. Each light guide part includes a light incident part facing the light source, and a light emitting part extending curvedly outward from the light incident part and extending along a side surface and a back side of the light source. A light guide / emission part that guides light incident on the light incident part and emits it from the light exit part,
The lighting device according to claim 1, wherein the light emitting unit of the first light guide unit and the light emitting unit of the second light guide unit have different arrangement heights or light emitting directions.   The lighting device according to any one of claims 1 to 3, wherein the plurality of second light guide portions of the light guide are formed by an air layer.   The light guide is spaced apart from each other along the circumferential direction of the central axis, and has a plurality of wedge-shaped cuts that taper toward the central axis. The illuminating device according to claim 4, wherein the light body portions are respectively formed. A plurality of heat dissipating fins provided on the outer periphery of the main body,
The lighting device according to claim 5, wherein the heat radiation fin is arranged in alignment with the plurality of cuts of the light guide.   The lighting device according to claim 1, further comprising a translucent cover that covers the light source and the light guide and is attached to the base material and emits light emitted from the light source to the outside.   The lighting device according to any one of claims 1 to 7, comprising a plurality of light sources arranged in a circle.   The lighting device according to any one of claims 1 to 8, wherein the lighting device is a light bulb-type lighting device having an LED light source that simulates an incandescent light bulb.

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