JP2014102995A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device of a bulb shape which can provide high light intensity in the lateral surface direction even when using an LED light source or the like, can provide visual quality like the conventional filament lamp capable of directly seeing a filament or a candle by using the LED light source.SOLUTION: A lighting device of a bulb shape includes: a substrate 2 having a top face 2a; a light source 4 arranged on a substrate top face; and a translucent cover 6 which is formed in a dome shape having a lower end opening 6a, has transparency, has the lower end opening side fixed to the substrate top face and covers a light source therewith. The translucent cover is formed such that a thickness of a wall part is smaller than the diameter of the lower end opening. The translucent cover 6 has a plurality of prisms 10 disposed on the whole region of a dome-shaped inner surface or outer surface, the prisms change a latitude direction of light beam made incident to the southern hemisphere direction of the translucent cover when the vertex of the dome-shaped translucent cover is set as north pole and emit the light and a virtual image of the light source is formed on a position floated up from the substrate top face when being viewed through the translucent cover.

Description

    This embodiment relates to a light bulb-type lighting device using a light source having a narrow light distribution that is limited in a surface normal direction and mounted like a light emitting diode (LED).

  Incandescent light bulbs and fluorescent lamps have been widely used as lighting devices, but have problems such as lifetime, luminous efficiency, mercury contamination, and ultraviolet light leakage. 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.

  However, light from a light source mounted on a mounting substrate such as an LED light source emits light strongly in the normal direction of the mounting substrate, and has directivity that does not emit light from the side surface to the back surface. Therefore, when a conventional incandescent light bulb with a nearly uniform light intensity distribution from the front to the back is replaced with a light bulb-type lighting device using an LED light source, the brightness of the ceiling and walls changes significantly, resulting in a different illuminance space. End up.

  Especially for chandeliers produced from candles, lighting devices that can directly view filaments of incandescent bulbs like flames are preferred, and they shine like dots in the direction of the side surface and reflect off to the surrounding scattering accessories. A brilliant lighting device is realized. However, in an illuminating device using an LED light source, it has been difficult to realize an illuminating device having the same appearance as such a filament direct-view incandescent bulb or candle.

Japanese Patent No. 4290887 JP-A-2005-05546 Japanese Patent No. 4945690 JP 2011-142060 A JP 2012-64558 A JP 2012-74264 A JP 2012-146450 A

  The present invention provides a light bulb-shaped illumination device that achieves the appearance of an incandescent bulb or a candle that has a high luminous intensity in the lateral direction even when an LED light source or the like is used and a conventional filament is directly viewed by the LED light source. It is in.

According to the embodiment, the lighting device has a base material having a top surface, a light source disposed on the base material top surface, a dome shape having a lower end opening, and has transparency, and the base material top surface A translucent cover that is fixed to the lower end opening side and covers the light source,
The translucent cover is formed such that the wall thickness is smaller than the diameter of the lower end opening,
The translucent cover has a plurality of prisms provided over the entire area of the inner surface or outer surface of the dome shape, and the prism is a latitude angle of the incident light when the vertex of the dome shape translucent cover is the north pole. Is emitted in the direction of the southern hemisphere of the translucent cover, and when viewed through the translucent cover, a virtual image of the light source is formed at a position raised from the top surface of the substrate.

FIG. 1 is a cross-sectional view showing a light bulb-shaped illumination device according to a first embodiment. FIG. 2 is a cross-sectional view of the lighting device. FIG. 3 is a view showing a ray trajectory of the illumination device. FIG. 4 is a view showing a light distribution of the lighting device. FIG. 5 is a diagram illustrating how the light bulb illuminates when viewed from the side of the light bulb-shaped illumination device according to the first embodiment. FIG. 6 is a cross-sectional view illustrating a light bulb-shaped illumination device according to a second embodiment. FIG. 7 is a diagram illustrating a prism configuration of the light bulb-type lighting device according to the second embodiment. FIG. 8 is a diagram showing a modification of the prism form of the light bulb-type lighting device according to the second embodiment. FIG. 9 is an enlarged perspective view showing a part of the prism according to the modified example. FIG. 10 is a cross-sectional view illustrating a light bulb-shaped illumination device according to a third embodiment. FIG. 11 is a diagram illustrating a light ray trajectory of a light bulb-shaped illumination device according to a third embodiment. FIG. 12 is a view showing a light distribution of the light bulb-type lighting device according to the third embodiment. FIG. 13 is a diagram illustrating how the light bulb-shaped illumination device according to the third embodiment is illuminated when viewed from the side.

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 showing an LED bulb 1 as a bulb-type lighting device according to the first embodiment. The LED bulb 1 has a rotationally symmetric shape with respect to the central axis C.

  The LED bulb 1 includes a base material 2 having a flat base material top surface 2a on the front surface, a light source 4 composed of LEDs mounted on the base material top surface 2a, and a light source 4 arranged on the base material top surface 2a. A dome-like translucent cover 6 covering the dome.

  The base material 2 is a metal casing and a heat dissipation member, and has a substantially circular base top surface 2a formed in a substantially truncated cone shape and flat at the upper end, and a base 8 is provided at the lower end of the base material 2. Is provided. The light source 4 is disposed at the center of the base material top surface 2a. A drive circuit 11 that drives the light source 4 is housed inside the base material 2. The power supplied from the base 8 is supplied to the light source 4 by the drive circuit 11 to emit light. The base material 2 holds the translucent cover 6 and the base 8 to form the outer shape of the LED bulb 1 and also serves as a heat sink and a heat sink for the heat of the light source 4.

  The translucent cover 6 is formed of a transparent resin in a vertically long dome shape, and has a circular lower end opening 6 a and a dome apex T located on the central axis C. That is, the translucent cover 6 is formed in a vertically long shape whose height along the central axis C is larger than the diameter of the lower end opening 6a. And the translucent cover 6 is arrange | positioned coaxially with the center axis | shaft C by fixing the lower end by the side of the lower end opening 6a to the base-material top surface 2a of the base material 2, and further covers the light source 4. FIG. The translucent cover 6 has a wall portion whose wall thickness is smaller than the diameter of the lower end opening 6a.

  The translucent cover 6 integrally has a plurality of prisms formed on at least one of its dome-shaped inner surface or outer surface. In the present embodiment, a plurality of prisms 10 are formed in the entire area of the dome-shaped inner surface of the translucent cover 6. Each prism 10 has, for example, a triangular cross section, and is formed in an annular shape coaxial with the central axis C. The plurality of prisms 10 are formed side by side from the dome apex T to the lower end opening 6a.

  The prism 10 functions to emit light (broken arrow) incident from the light source 4 by bending the light beam in the southern hemisphere latitude direction of the translucent cover 6 when the dome apex T is the north pole (solid arrow). Thereby, the prism 10 functions so as to form the virtual image S of the light source 4 at a position floating between the base surface 2a and the dome apex T when the light source 4 is viewed from the outside of the translucent cover 6. To do.

  The translucent cover 6 is formed of a transparent material, and the light beam (dashed arrow) from the light source 4 is bent by the prism 10 in the southern hemisphere direction only without changing the longitude direction. Can be lifted in the vertical direction (direction along the central axis C) without expanding the area of.

  In the present embodiment, the virtual image S of the light source 4 is configured to extend vertically from the base surface 2a to the vicinity of the dome apex T of the translucent cover 6 like a candle flame. Accordingly, it is possible to make it appear as if there is a candle flame near the center of the translucent cover 6 while using the light source 4 made of LED.

  2 and 3 are a cross-sectional view of the actually designed LED bulb 1 and a diagram showing its light path by optical analysis. FIG. 4 shows the light distribution of the LED bulb 1, and FIG. 5 is a diagram showing how the LED bulb 1 is seen from the side.

  As shown in FIGS. 2 to 5, according to the first embodiment, the transparent light-transmitting cover 6 causes the virtual image of the light source 4 mounted on the top surface 2a of the base material to emerge so that the flame of the candle emits light. You can make it look like you are doing. In particular, the direction in which the prism 10 emits in the entire area of the light-transmitting cover 6 is the side surface direction, so that the light distribution of the LED bulb 1 is extremely concentrated in the side surface direction and is transparent like a candle flame. Light can be emitted vertically from the base of the light cover 6 to the top, and the appearance of a lighting fixture having a light scattering reflection component around the side surface such as a chandelier can be improved.

  In the LED light bulb 1, the translucent cover 6 is an essential component even in a general light bulb, and the LED light bulb 1 is realized without increasing the number of components such as a lens and hence without deteriorating the light utilization efficiency. It has a configuration that is excellent in terms of mass productivity.

  In addition, since the translucent cover 6 is not close to the light source 4 as in the conventional lens and is located far from the light source 4, the light beam reflected from the translucent cover 6 toward the light source 4 is retransmitted to the light source 4. The probability of absorption is small and light utilization efficiency is improved. Even if the specifications of the light source 4 are changed, the influence on the optical characteristics becomes insensitive, and there is almost no need to individually modify the design according to detailed specifications of various LED light sources. Therefore, the translucent cover 6 can be shared by a wide range of products.

  According to the first embodiment configured as described above, even if an LED light source or the like is used, the appearance of an incandescent light bulb or a candle having a high luminous intensity in the lateral direction and a direct view of a conventional filament is obtained. A light bulb-shaped lighting device realized in the above can be obtained.

  In the first embodiment, the prism 10 is provided on the dome-shaped inner surface of the translucent cover 6. However, the present invention is not limited thereto, and a plurality of prisms may be provided on the dome-shaped outer surface, or both the inner surface and the outer surface are provided. A prism may be provided.

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

(Second Embodiment)
FIG. 6 is a cross-sectional view showing an LED bulb 1 as a bulb-shaped illumination device according to the second embodiment, and FIG. 7 is a perspective view showing a prism formed on the inner surface of the light-transmitting cover. In the second embodiment, the LED bulb 1 is basically the same as in the first embodiment, but the translucent cover 6 is not a vertically long dome, but a substantially hemispherical dome. The translucent cover 6 is formed of a transparent material, and a plurality of prisms 10 are integrally formed on the inner surface thereof. Each prism 10 has a triangular or wedge-shaped cross section, for example, and is formed in an annular shape coaxial with the central axis C. The plurality of prisms 10 are formed side by side from the dome apex T to the lower end opening 6a.

  In the second embodiment, the translucent cover 6 has a shape different from that of the first embodiment, but the action of raising the virtual image S of the light source 4 to be shown is the same as that of the first embodiment. Therefore, also in the second embodiment, there is obtained a light bulb-type lighting device that has a high luminous intensity in the side surface direction and realizes the appearance like an incandescent light bulb or a candle in which a conventional filament is directly viewed with an LED light source.

  In the first and second embodiments, the prism 10 has a basic shape that is concentrically rotated as shown in FIG. 7, but in this case, if the prism arrangement pitch is rough, the prism 10 The stripes are easy to see. In order to improve such appearance, the prisms 10 are arranged in a zigzag manner in the circumferential direction around the central axis C (longitude direction when the dome apex is the north pole) as in the modified examples shown in FIGS. You may improve the appearance.

(Third embodiment)
FIG. 10 is a cross-sectional view showing an LED bulb as a bulb-type illumination device according to the third embodiment, FIG. 11 is a diagram showing a light path of the LED bulb, and FIG. 12 is a light distribution of the LED bulb. FIG.

  As shown in FIGS. 10 and 11, according to the LED bulb 1 according to the third embodiment, the translucent cover 6 is formed in a bulging spherical shape, and the lower end opening 6 a side is the base material top surface of the base material 2. It is fixed to 2a. A plurality of prisms 10 are provided on the outer surface of the translucent cover 6. Each prism 10 has a triangular or wedge-shaped cross section, for example, and is formed in an annular shape coaxial with the central axis C. The plurality of prisms 10 are formed side by side from the dome apex T of the translucent cover 6 to the lower end opening 6a.

The controllability is improved when the prism 10 is provided outside the translucent cover 6. In the present embodiment, as shown in FIG. 11, by improving controllability, the light beam (solid arrow) is designed to be emitted from the center of the light-transmitting cover 6 over the entire area of the light-transmitting cover 6. S is narrowed down to a small point.
FIG. 13 is a diagram illustrating how the LED bulb shines when the LED bulb 1 is viewed from the side. As shown in the figure, the light source image (virtual image) S appears to be concentrated and floated in the vicinity of the center of the translucent cover 6.

  Also in the third embodiment configured as described above, there is a light bulb-shaped illuminating device that realizes an appearance like an incandescent light bulb or a candle with a high luminous intensity in the lateral direction and a conventional filament directly viewed with an LED light source. can get.

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.
In addition, the surface of the translucent cover 6 is subjected to a graining process, or the material itself of the translucent cover 6 is made of some milk white resin, thereby making it difficult to see through the translucent cover 6 or blurring the luminescent image. May be.

  Although the above-described embodiment has been described as an LED bulb, the lighting device according to the present invention can be applied to street lamp lighting as long as it is a combination of a directional light source and a translucent cover surrounding the light source. it can.

DESCRIPTION OF SYMBOLS 1 ... LED bulb, 2 ... Base material, 2a ... Base material top surface, 4 ... Light source, 6 ... Translucent cover,
6a ... lower end opening, 10 ... prism, 11 ... drive circuit, S ... virtual image

Claims (7)

A substrate having a top surface;
A light source disposed on the top surface of the substrate;
A transparent cover that is formed in a dome shape having a lower end opening and has transparency, and the lower end opening side is fixed to the top surface of the base material and covers the light source,
The translucent cover is formed such that the wall thickness is smaller than the diameter of the lower end opening,
The translucent cover has a plurality of prisms provided over the entire area of the inner surface or outer surface of the dome shape, and the prism is a latitude angle of the incident light when the vertex of the dome shape translucent cover is the north pole. Is emitted in the direction of the southern hemisphere of the translucent cover, and when viewed through the translucent cover, a virtual image of the light source is formed at a position raised from the top surface of the base material. apparatus.   The light bulb-shaped illumination device according to claim 1, wherein the light-emitting illumination device has a light distribution that emits light with the strongest light intensity in a lateral direction of the translucent cover.   The light bulb-shaped illumination device according to claim 1, wherein the virtual image of the light source has a dot shape.   The light bulb-shaped illumination device according to claim 1, wherein the virtual image of the light source is a vertically long image extending along a central axis of the translucent cover.   The light-bulb-shaped lighting device according to claim 4, wherein the translucent cover is formed in a vertically long shape having a height along a central axis larger than a diameter of the lower end opening.   The bulb-shaped illumination device according to any one of claims 1 to 3, wherein the translucent cover has a spherical shape having a lower end opening.   The bulb-shaped illumination device according to claim 1, wherein the prisms are arranged in a zigzag pattern with respect to the longitudinal direction of the translucent cover.

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