JP2013251080A - Lighting device - Google Patents

Abstract

An illumination device capable of uniformly irradiating light from a light source is provided.
A lighting device includes a base material 2, a directional light source 4 that emits visible light, covers at least a front surface of the light source, and emits light emitted from the light source to the outside. A translucent cover 5 having a translucent area to be emitted. The translucent cover has a plurality of surfaces facing different directions, and the transmissive region is formed of a material containing a scattering filler and has a transmittance of 70% or less.
[Selection] Figure 1

Description

  Embodiments described herein relate generally to an illumination device that uses a light source with high directivity such as a light emitting diode (LED).

As lighting devices, lighting devices such as straight tube fluorescent lamps and light bulbs are widely used. As a straight tube type fluorescent lamp, a linear or circle type fluorescent lamp is used, and as a light bulb type lighting device, an incandescent lamp using light emission by the heat of a filament or a fluorescent lamp bent in a light bulb is housed in the bulb. Although lamp-type light bulbs have been widely used, they have problems such as short life, infrared emission (ultraviolet emission), mercury use problems, and luminous efficiency.
In recent years, LED light sources and EL light sources have been developed as techniques for solving these problems, and the use of LED light sources for straight-tube illumination devices is accelerating.

  However, a general surface-mount type LED light source emits light strongly in the normal direction of the mounting substrate, and when the angle formed with the normal direction of the mounting substrate is θ, the light intensity is attenuated in proportion to cos θ. Has directivity. This is because the structure of a general LED light source is such that the LED chip that emits primary light is covered in a planar shape with a protective layer containing a phosphor that converts primary light to secondary light. is there. For this reason, the light intensity distribution is such that almost no light is emitted from the side of the mounting substrate toward the back. Therefore, when a conventional straight tube fluorescent lamp having a substantially uniform light intensity distribution from the front to the back is replaced with an LED, the brightness of the ceiling or wall changes significantly, resulting in a different illuminance space. Furthermore, since it becomes the point light source which used LED as the luminescent point, it will become a very dazzling and unpleasant light source.

  When using a straight tube illumination device using such an LED in a showcase in which a product is placed on the lower side and a product tag is on the front side, a straight tube illumination device that irradiates the product tag, The straight tube illumination device to be irradiated is arranged above the showcase in each direction. With such a configuration, each of the product tag and the product can be illuminated brightly.

Japanese Patent No. 4076329 Japanese Patent No. 4290887 JP 2010-27282 A JP-A-2005-05546

  However, due to the directivity unique to the LED described above, the product tag located relatively close to the LED lighting device causes uneven brightness of the LED to appear and causes unevenness. Further, the products placed in the showcase are similarly reflected in the unevenness of the LEDs, which causes a problem of deteriorating the appearance of the product tag and the product. In addition, the configuration of the lighting device has a problem that two parts of LEDs arranged on a straight line are necessary and the structure becomes complicated.

  In addition, when an existing LED fluorescent lamp with high directivity is used for the ceiling lighting of a store, there is a problem that the light radiated in the direction of the ceiling or the side is weak and the store becomes dark.

  The present invention has been made in view of the above points. An object of the present invention is to provide an illumination device that can irradiate light from a light source uniformly with a simple structure or irradiate in a specific different direction. There is.

  According to the embodiment, the lighting device includes a base material, a directional light source that emits visible light, and a transparent region that covers at least a front surface of the light source and emits light emitted from the light source to the outside. A light cover, the light-transmitting cover has a plurality of surfaces facing in different directions, and the transmission region is formed of a material containing a scattering filler and has a transmittance of 70% or less.

FIG. 1 is a cross-sectional view showing a straight tube type LED lighting device according to a first embodiment. FIG. 2 is a cross-sectional view showing a showcase in which the lighting device is installed. FIG. 3 is a view showing a light distribution of the lighting device. FIG. 4 is a cross-sectional view of a lighting device according to a comparative example in which the cover surface of the translucent cover is formed with a curved surface. FIG. 5 is a cross-sectional view of the lighting device for explaining the operation of the cover surface of the translucent cover. FIG. 6 is a cross-sectional view of a lighting device according to a comparative example in which the cover surface of the light-transmitting cover is formed as a horizontally elongated vertical ellipse. 7 is a diagram showing a light distribution of the lighting device shown in FIG. FIG. 8 is a view showing a light distribution of the lighting device shown in FIG. FIG. 9 is a cross-sectional view showing a lighting device according to a first modification. FIG. 10 is a cross-sectional view illustrating a lighting device according to a second modification. FIG. 11 is a cross-sectional view showing a straight tube type LED lighting device according to a second embodiment. FIG. 12 is a cross-sectional view showing a straight tube type LED lighting device according to a third embodiment. FIG. 13 is a perspective view showing a light bulb-type LED lighting device according to a fourth embodiment. FIG. 14 is a cross-sectional view of a bulb-type LED lighting device according to a fourth 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 a straight tube type LED lighting device according to the first embodiment. The LED lighting device 1 has a rod-like three-dimensional shape obtained by extending the illustrated cross-sectional structure linearly. The straight tube type LED lighting apparatus 1 includes, as a base material, a bottom plate 2 that is a vertically long flat plate, a mounting substrate 3 that has a flat mounting surface on the front surface, and is disposed on the bottom plate 2. A light source 4 composed of a plurality of LEDs mounted in a straight line is provided, and a translucent cover 5 that irradiates the light emitted from the light source 4 to the outside. The LED as the light source 4 has directivity in which the luminous intensity of light emitted from the LED is strong in the normal direction of the light emitting surface and becomes zero on the back side. The translucent cover 5 is supported on the bottom plate 2 and covers the light source 4. The LED lighting device 1 is configured such that power is supplied by a separately provided drive circuit (not shown) and the light source 4 emits light.

  The translucent cover 5 has, for example, a shape obtained by bending a thin plate having a thickness of 1.5 mm into a substantially U shape, and a first cover surface 5a facing right front and a second cover surface facing left side. 5b. Here, the 1st and 2nd cover surfaces 5a and 5b are formed in the flat flat loose curved surface. The apex angle θ1 formed by the first cover surface 5a and the second cover surface 5b is, for example, approximately 80 degrees. Both lower ends on the opening side of the translucent cover 5 are fixed on the side edges of the bottom plate 2. The 1st cover surface 5a and the 2nd cover surface 5b are formed in the elongate rectangular shape extended along the row | line | column of the several light source 4 arrange | positioned along with the line form. Thereby, the translucent cover 5 covers the front side and the side of the light source 4. The first cover surface 5a having a large area forms an angle θ2 (approximately 30 degrees) with the bottom plate 2, and the second cover surface 5b having a small area forms an angle θ3 (approximately 80 degrees) with the bottom plate 2. The sum of θ1, θ2, and θ3 is 190 degrees because the first and second cover surfaces 5a and 5b are slightly curved.

  The translucent cover 5 has a translucent region that emits light emitted from the light source 4 to the outside. In the present embodiment, the translucent cover 5 forms a translucent region where the entire region can transmit light. The translucent cover 5 is made of milky white resin containing a diffusion filler, and the thickness and the density of the scattering filler are designed so that the transmittance is as low as 50%.

  When the transmittance of the translucent cover 5 is greatly reduced in this way, light from the light source 4 incident on the translucent cover 5 strays as shown by arrows in FIG. A luminous intensity distribution having a cos distribution with respect to the normal direction is formed. Specifically, when the transmissivity of the translucent cover 5 is lower than about 70%, it is strong in the normal direction of the surface of the translucent cover 5 almost regardless of the direction of light incident on the translucent cover 5 from the light source 4. The emission characteristics are shown. This is because the translucent cover 5 behaves as if it is a homogeneous surface light source, not depending on the light source, and the light distribution as an illuminating device depends only on the direction of the surface of the translucent cover 5. It becomes like this. That is, the transmittance of the translucent cover 5 is lowered, and the first cover surface 5a and the second cover surface 5b of the translucent cover are directed in different directions, so that the plurality of light sources 4 arranged in a line. It is possible to change a point light source consisting of a surface light source that irradiates two different directions.

  FIG. 2 is a cross-sectional view of a showcase in which the straight tube type LED lighting device 1 described above is installed. The showcase 10 includes a box-shaped main body 11 having a U-shaped cross section, a product tag 12 arranged at the top of the front opening of the main body 11, and an LED lighting device 1 arranged behind the product tag 12. I have. A product (not shown) is placed on the bottom surface of the main body 11. The LED lighting device 1 is arranged so that the first cover surface 5a of the translucent cover 5 faces downward and toward the product, and the second cover surface 5b of the translucent cover faces the back side of the product tag 12. ing.

  In the showcase 10 configured as described above, a light beam directed leftward slightly inclined downward is emitted from the second cover surface 5b of the LED lighting device 1, whereby the product tag 12 is illuminated, and the first cover surface is illuminated. A light beam directed downward to the right is emitted from 5a, and thereby the inside of the showcase 10, that is, the product is illuminated. Since both are illuminated by a light source that is converted into a surface light source, the grainy unevenness that has occurred in the prior art is eliminated, and an excellent-looking product display becomes possible.

  Furthermore, according to the present embodiment, the areas of the first cover surface 5a and the second cover surface 5b are different from each other, and the first cover surface 5a has a larger area than the second cover surface 5b. Thereby, since the light flux emitted from the first cover surface 5a is larger than the light flux emitted from the second cover surface 5b, the interior of the showcase 10 having a large area can be illuminated with sufficient brightness. That is, in this embodiment, the cross-sectional structure of the translucent cover 5 is asymmetric in this way, so that it is possible to irradiate a necessary amount of light in a necessary direction, and further irradiate with a surface light source. Therefore, uniform irradiation without graininess is possible.

FIG. 3 shows an actual measurement of the light distribution distributed by the LED lighting device 1 of FIG.
As shown in FIG. 3, in the light distribution, strong light is emitted in the direction in which the first cover surface 5a faces, weak light is emitted in the direction in which the second cover surface 5b faces, and the rest is useless. To avoid irradiation. As a result, the showcase as shown in FIG. 2 can be illuminated brightly and without waste.

  Conventionally, two line-shaped light sources directed in different directions were necessary. However, since the LED lighting device 1 requires only one line-shaped light source, it is possible to reduce the size of the lighting device at low cost. Become. That is, according to the present embodiment, a small and high-performance lighting device can be provided at low cost. Moreover, according to this embodiment, although the light source 4 is arrange | positioned in the approximate center of the baseplate 2, it does not stick to this structure in particular, As the arrangement | positioning which brought the light source 4 close to one side edge side of the baseplate 2 Also good. However, the amount of light emitted from the cover surface on the side closer to the light source 4 increases, and therefore the arrangement position of the light source 4 may be appropriately selected according to the use environment. If the light source 4 is moved too close to the end of the bottom plate 2, the distance between the light-transmitting cover 5 and the light source 4 is narrowed, and light re-enters the light source 4 due to reflection from the light-transmitting cover 5. It causes problems such as changes. Although it depends on the shape of the translucent cover 5, in general, when the width of the bottom plate 2 is 1, the light source 4 is located at a position separated from the side edge of the bottom plate by ¼ to ¾ of the width of the bottom plate 2. It is preferable to arrange in.

  Further, in the light distribution shown in FIG. 3, the light is extremely weakened in the direction hitting the middle part of the first and second cover surfaces 5a and 5b, but when this region also has a gentle light distribution, The distribution of light distribution can be controlled with an arbitrary degree of smoothness by connecting the first and second cover surfaces 5a and 5b in a rounded manner.

  FIG. 4 shows an illumination device according to a first modification in which the first cover surface 5a and the second cover surface 5b are gently connected. By adopting such a configuration, it is possible to eliminate the extreme light distribution distribution (in the direction where the luminous intensity is weak) as shown in FIG. 3 and to obtain a gentle light distribution. In addition, since it is necessary to make the design surface and protrusions injured smoothly, there is a configuration in which main surfaces facing different directions are substantially connected in a rounded form as shown in FIG. 4 instead of FIG. desirable.

  In this embodiment, the translucent cover 5 can be manufactured by extrusion molding or injection molding, or can be manufactured by bonding two flat plates. What is necessary is just to select the manufacturing method of a translucent cover suitably according to a use, a production quantity, etc.

  As described above, the transmissivity of the translucent cover 5 starts to be about 70%, and the effect is increased by further lowering the transmittance. However, when the transmittance is about 30% or less, the effect is saturated. It will only lead to degradation of efficiency. Therefore, it is desirable to set the transmittance of the translucent cover 5 within a range of approximately 30% to 70%. However, if the transmissivity of the translucent cover 5 is about 60% to 70%, the unevenness of the light source 4 may remain on the first and second cover surfaces 5a and 5b. By setting the transmittance of the light-transmitting cover 5 to 60% or less, the unevenness of the light source 4 can be almost eliminated. Therefore, when the unevenness occurs, the transmittance of the light-transmitting cover 5 may be further reduced. .

  As described above, the LED lighting device 1 has an asymmetric structure with the normal line of the bottom plate 2 as the central axis, but is not particularly limited to an asymmetric structure. If the substantial plane of the translucent cover is in a different direction, the same effect as described above can be obtained.

  FIG. 5 is a cross-sectional view of the lighting device in which the first and second cover surfaces of the translucent cover 5 are formed as a plane, and FIG. 6 is a cross-sectional view of the lighting device in which the cover surface of the translucent cover is formed as a curved surface. As described above, the light incident on the translucent cover 5 changes so as to have a cos distribution luminous intensity with respect to the normal direction of the surface of the translucent cover 5 regardless of the incident direction. Therefore, as shown in FIG. 5, when the translucent cover 5 is constituted by a plurality of planes, for example, light emitted from the first cover surface 5 a has a light intensity distribution having the same direction at any position. On the other hand, as shown in FIG. 6, when the translucent cover 5 is formed in a substantially elliptical shape, a strong light intensity distribution is formed in the lateral direction near the bottom plate 2, and a strong light intensity distribution in the front direction near the top. Is formed.

  FIGS. 7A and 7B are obtained by actually measuring the light distribution by the lighting device shown in FIG. The two light distributions are the difference in height of the elliptical light-transmitting cover 5, and when the light distribution is increased, the light distribution is mainly a side surface in which the front luminous intensity is relatively lowered.

  Such a lighting device that can illuminate a wide area with symmetry is sometimes unsuitable for the showcase described above, but store ceiling lighting can brighten the store impression because it can irradiate the ceiling, walls, or outside the store. Can be given.

  FIG. 9 shows a lighting device according to a modification, in which the thickness of the first cover surface 5a is formed so as to increase from the apex. Usually, the transmittance of the thick plate portion is relatively smaller than the transmittance of the thin plate portion. Therefore, with such a configuration, the distribution of the light beam emitted from the first cover surface 5a can be changed, and thus the illuminance distribution in the depth direction of the showcase 10 can be controlled.

  In addition, according to a present Example, it is set as the structure which becomes thick so that plate | board thickness leaves | separates from a vertex, However, The reverse case may be sufficient and should just select suitably according to the depth, shape, etc. of the showcase 10. Furthermore, it goes without saying that the same applies to the cover surface 51 as well.

  In FIG. 10, the density of the diffusion filler on the second cover surface 5b is larger than that of the first cover surface 5a, and the transmittance of the second cover surface 5b is lower than the transmittance of the first cover surface 5a. It is configured.

  With such a configuration, the amount of light emitted from the second cover surface 5b can be reduced, which is effective in the case of a small product tag 12.

  According to the present embodiment, the transmittance of the second cover surface 5b is set to be lower than the transmittance of the first cover surface 5a. It may be changed depending on the shape and size of the showcase 10 and the product tag 12.

  The angle θ1 formed by the first cover surface and the second cover surface of the translucent cover 5 is not limited to the present embodiment, and is optimally appropriate depending on the position and size of the product tag and the size and shape of the showcase. Just turn in the direction. However, when the angle θ1 is larger than 120 degrees, the light separation effect is weakened, and the effect of the above-described embodiment cannot be exhibited. Therefore, normally, the angle θ1 is preferably set to 120 degrees or less. The light sources 4 are not limited to a single row, and may be arranged in a plurality of rows and in a straight line.

  As described above, according to the present embodiment, it is possible to provide an illumination device that can uniformly irradiate articles such as a product tag and a product with light sources arranged on a straight line.

  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. 11 is a cross-sectional view showing a straight tube type LED lighting apparatus according to the second embodiment. The LED lighting device 1 has a rod-like three-dimensional shape obtained by extending the cross-sectional structure shown in FIG. 11 linearly.

  The basic configuration of the lighting device 1 is the same as that of the lighting device according to the first embodiment. However, in the second embodiment, the first cover surface 5a and the second cover surface 5b of the translucent cover 5 are respectively The curved surface is convex toward the light source 4.

By adopting such a configuration, the distribution width of the luminous intensity distribution emitted in the respective directions from the first and second cover surfaces 5a and 5b can be narrowed, which is effective when it is desired to irradiate a smaller area. It becomes composition. That is, when the first and second cover surfaces 5a and 5b are substantially flat surfaces or curved surfaces that are convex in the direction of the light source 4, it is possible to irradiate light intensively in the normal direction.
Also in the second embodiment, an illuminating device that can uniformly irradiate with a plurality of light sources arranged in a straight line is obtained.

(Third embodiment)
FIG. 12 shows a cross section of the straight tube type LED lighting device 1 according to the third embodiment.
In the third embodiment, the basic configuration of the LED lighting device 1 is the same as that of the first embodiment, but the translucent cover 5 is positioned between the first cover surface 5a and the second cover surface 5b. A reflective cover surface 6 is provided. The reflective cover surface 6 extends substantially parallel to the bottom plate 2 and faces the light source 4. By providing the reflective cover surface 6 on the translucent cover 5 in this way, the angle θ formed by the first cover surface 5a and the second cover surface 5b can be changed, and the irradiation direction of light from the translucent cover 5 can be changed. It becomes possible to control. In addition, also in the LED lighting device 1 according to the third embodiment, it is possible to obtain the same functions and effects as those of the first embodiment described above.

(Fourth embodiment)
FIG. 13 is a perspective view showing a bulb-type LED lighting device 7 according to the fourth embodiment, and FIG. 14 is a cross-sectional view of the LED lighting device.

  As shown in FIGS. 13 and 14, in the fourth embodiment, the basic configuration of the LED lighting device 7 is the same as that of the first embodiment, but the bottom plate 2 is formed in a substantially square shape. A mounting substrate 3 is disposed at the upper center of the light source, and a light source 4 composed of LEDs is disposed at the upper central portion of the mounting substrate 3. The translucent cover 5 has four cover surfaces and has a quadrangular pyramid shape with the bottom plate 2 as a bottom surface. The angle of each cover surface with respect to the bottom plate 2 is set to about 45 degrees.

  With this configuration, light beams having an angle of 45 degrees are emitted from each cover surface in four directions. Therefore, when the LED lighting device 7 is used for lighting a square room, for example, it becomes possible to illuminate all the walls in all four directions equally brightly.

  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.

DESCRIPTION OF SYMBOLS 1 ... LED lighting apparatus, 2 ... Bottom plate (base material), 3 ... Mounting board, 4 ... Light source (LED),
5 ... translucent cover, 5a ... first cover surface, 5b ... second cover surface, 6 ... reflective cover surface,
7 ... LED lighting device

Claims (7)

A substrate;
A directional light source that is provided on the substrate and emits visible light;
A translucent cover that covers at least the front surface of the light source and has a translucent region that emits light emitted from the light source to the outside; and
The translucent cover has a plurality of surfaces facing different directions, and the transmissive region is formed of a material containing a scattering filler and has a transmittance of 70% or less.   The illuminating device according to claim 1, wherein a transmittance of a transmissive region of the translucent cover is 30% or more.   The lighting device according to claim 1, wherein the plurality of surfaces facing different directions are flat surfaces.   The lighting device according to claim 1, wherein the plurality of surfaces facing different directions are surfaces curved in a convex manner in a light source direction.   The lighting device according to claim 1, wherein the translucent cover is formed non-axisymmetrically with respect to a normal line of the base material.   The illuminating device according to any one of claims 1, 3, 4, and 5, wherein an angle formed by a plurality of surfaces of the translucent cover is 120 degrees or less. A plurality of light sources arranged in a straight line in at least one row on the substrate;
The lighting device according to claim 1, wherein the translucent cover has two elongated cover surfaces along the row of the light sources.

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