WO2014045644A1 - Illumination device and illumination lens - Google Patents

Abstract

According to an embodiment, an illumination device is provided with a light source (14) and an illumination lens (16) for introducing light emitted from the light source, controlling the introduced light, and emitting the light towards a surface being irradiated. The illumination lens has a concave part (24) to which the light from the light source and which is formed in the center part of the lower side, an outside upper surface (22a) for emitting the introduced light, and an outside wall surface (22b). The concave part (24) is formed by an inside upper surface (24a) and an inside wall surface (24b). At least a part of the light introduced from the light source to the inside wall surface is refracted and emitted upward toward the outside upper surface primarily at the outside wall surface, and light introduced from the inside upper surface is primarily emitted from the outside upper surface.

Description

Illumination device and illumination lens

Embodiment described here is related with the illuminating device and the lens for illumination used for this illuminating device.

The lighting device is required not only to illuminate the space but also to suppress glare. In particular, in a lighting device of a type that irradiates from the ceiling side to the floor side, it has been required to suppress the light intensity leaking in the oblique side direction in which the angle from the vertical direction of the lighting device is greater than 60 degrees. Further, in a lighting device that irradiates a specific area in front of the lighting device, such as a desk light or a spotlight, light leaking in the oblique side surface direction is wasted, so that it is desired to block the light.

Therefore, an illuminating device including a diffusion plate has been proposed in order to suppress the light intensity leaking in the oblique side surface direction. In addition, a configuration has been proposed in which a plurality of walls facing the vertical direction are installed in front of the lighting device to suppress the light intensity leaking in the oblique side surface direction.

In recent years, point-like light sources such as light emitting diodes (LEDs) have begun to be used in place of conventional fluorescent lamps and incandescent lamps. There has been proposed a configuration in which a lens is attached to an LED so that light emitted in the lateral direction is totally reflected forward.

JP 04-267001 A Japanese Patent Laid-Open No. 04-87204 Japanese Patent Laid-Open No. 06-20503 Japanese Utility Model Publication No. 06-28725 JP 2003-264317 A JP 2005-228623 A

In a normal desk light, light emitted from an LED light source with an angle θ of about 60 degrees or more is not irradiated on the desk, and is wasted light. On the other hand, as described above, the LED light source has directivity in which the luminous intensity is attenuated in proportion to cos θ. Therefore, the amount of light flux with θ of 60 degrees or more is about 20% of the amount of light flux emitted from the LED light source, which greatly deteriorates the light use efficiency of the desk light.

Also, unlike incandescent bulbs and fluorescent lamps, the LED light source is a very small light source and therefore has a very high luminance. Usually, the desk light is often placed slightly above the eye level. Therefore, since the LED light source can be directly seen from the lateral direction, a great discomfort is given.

In addition, when the object to be illuminated is a flat surface such as a floor or a desk, it is desirable to have a light distribution that keeps the illuminance constant even when the object is slightly inclined with respect to the position directly below the lighting device.

The present invention has been made in view of the above points, and its problems are to improve the light use efficiency, reduce unpleasant glare, and make the illuminance uniform. To provide a lens.

According to the embodiment, the illumination device includes a light source, and an illumination lens that receives the light emitted from the light source and controls the incident light to be emitted toward the irradiated surface.
The illumination lens has a recess formed in a lower central portion for receiving light from the light source, an outer upper surface for emitting the incident light, and an outer wall surface, and the recess has an inner upper surface and an inner surface. And at least part of the light incident on the inner wall surface from the light source is mainly refracted and emitted upward from the outer wall surface, and the light incident from the inner upper surface is mainly the Outgoes from the outer top surface.

FIG. 1 is a perspective view showing an illumination apparatus according to the first embodiment. FIG. 2 is a cross-sectional view of the illumination device along line AA in FIG. FIG. 3 is an enlarged cross-sectional view showing a part of the illumination device. FIG. 4 is an enlarged cross-sectional view illustrating a lens portion for explaining the lens action of the illumination lens in the illumination device. FIG. 5 is a view showing a luminous intensity distribution of the illumination device according to the first embodiment. FIG. 6 is an enlarged cross-sectional view illustrating a part of the lighting apparatus according to the second embodiment. FIG. 7 is a view showing a luminous intensity distribution of the illumination device according to the second embodiment. FIG. 8 is an enlarged cross-sectional view of a part of the lighting apparatus according to the third embodiment. FIG. 9 is an enlarged cross-sectional view illustrating a part of the illumination device according to the fourth embodiment.

Hereinafter, illumination devices according to various embodiments will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a perspective view showing an appearance of the illumination device according to the first embodiment, FIG. 2 is a cross-sectional view of the illumination device along line AA in FIG. 1, and FIG. 3 is an enlarged view of an illumination lens. It is sectional drawing shown.

As shown in FIGS. 1 and 2, the lighting device 10 covers a substrate 12, a plurality of light sources mounted on the substrate 12, for example, a plurality of LEDs 14, the substrate 12 and the light sources, and a plurality of LEDs. And a lens cover 18 having a plurality of illumination lenses 16.

The substrate 12 is formed in, for example, a thin disk shape. On the back side of the substrate 12, a heat radiating plate 20 having substantially the same shape and dimensions as this substrate is provided and is in close contact with the substrate 12. The plurality of LEDs 14 are arranged side by side at appropriate intervals over almost the entire surface of the substrate 12. The LED 14 is turned on by drive power generated by a drive circuit (not shown) connected to the substrate 12.

The LED 14 emits strong light in the normal direction perpendicular to the substrate 12, that is, the central axis direction of the LED, and when the angle from the normal direction is θ, the light intensity in the side surface direction becomes weaker in proportion to cos θ. It has the directivity to go. Therefore, when there is no illumination lens 16, the light distribution is such that light leaks even in an oblique side surface direction with an angle θ of 60 degrees or more, and the user feels dazzling.

The lens cover 18 including the plurality of illumination lenses 16 is formed in a disk shape with a transparent resin such as polycarbonate or acrylic. The peripheral edge of the lens cover 18 is engaged with and supported by the substrate 12 and the heat sink 20. Accordingly, the lens cover 18 faces the substrate 12 and the plurality of LEDs 14 with a gap therebetween, and covers the plurality of LEDs 14.

The plurality of lenses 16 formed integrally with the lens cover 18 are disposed to face the front surfaces of the corresponding LEDs 14, respectively. The unit of one LED 14 and the lens 16 has a shape obtained by rotating the cross section shown in FIGS. 2 and 3 with respect to the central axis.

As shown in FIGS. 2 and 3, each lens 16 that controls incident light and emits it toward the irradiated surface is formed in a substantially truncated cone shape or a cylindrical shape, and is placed on the substrate 12 and the LED 14. Are arranged coaxially with the LED 14. The lens 16 includes a concave portion 24 in which light from the LED 14 enters a central portion on the lower surface side facing the LED 14, an outer upper surface 22a extending substantially parallel to the substrate 12, and a concave portion extending from the outer upper surface 22a toward the lens lower end surface 22c. 24 and an outer wall surface 22b located around 24. In the present embodiment, the outer wall surface 22b is formed in a substantially truncated cone shape having a small diameter on the LED 14 side, for example. The light that enters the lens 16 from the recess 24 is emitted from the outer upper surface 22a and the outer wall surface 22b.

The recess 24 is opposed to the LED 14 with a gap and is substantially parallel to the substrate 12 and has a substantially circular inner upper surface 24a, and a substantially frustoconical shape extending from the periphery of the inner upper surface 24a to the lower end surface 22c of the lens 16. And an inner wall surface 24b. The recess 24 is formed and arranged coaxially with the optical axis or the central axis of the LED 14.

In the inner upper surface 24a and the inner wall surface 24b defining the recess 24, when the angle formed with the direction perpendicular to the LED 14 (normal direction) is θ, at least a portion located in a region where θ is 60 degrees or more, The inner wall surface 24b is used.

In the illuminating device 10 configured in this way, the light beam incident from the LED 14 draws a locus as shown in FIG. That is, at least a part or all of the light that has entered the lens 16 from the inner wall surface 24b is refracted by the inner wall surface 24b and the outer wall surface 22b, bent upward (in a direction away from the substrate 12), and emitted. The light that has entered the lens 16 from the inner upper surface 24a is refracted from the inner upper surface 24a and the outer upper surface 22a and is emitted upward.

In this embodiment, the angles of the inner wall surface 24b and the outer wall surface 22b of the lens 16 are adjusted so that light incident from the inner wall surface 24b is bent upward by about 20 to 30 degrees. The lens 16 mainly functions to deflect light emitted from the LEDs 14 in the oblique side surface direction with an angle θ of 60 degrees or more so that the angle θ is within 60 degrees. Further, the lens 16 functions to emit light incident from the inner upper surface 24a by following the incident angle as it is. With such an action of the lens 16, the light distribution of the illumination device 10 has the light intensity distribution shown in FIG. 5, and the light emitted in the lateral direction with the angle θ of 60 degrees or more can be greatly reduced. Therefore, the light that is not irradiated on the desk can be significantly reduced, and the illumination device 10 that is not dazzling when viewed from the side can be obtained.

In a lens that totally reflects the light emitted from the LED in the lateral direction as shown in the prior art, the emitted light becomes a spot beam concentrated in the substantially vertical direction, and leaks in the lateral direction with an angle θ of 60 degrees or more. Although light is lost, it is difficult to realize a light intensity distribution in which the irradiation angle is expanded to about 90 degrees as shown in FIG. In order to eliminate the leakage light in the lateral direction where the angle θ is 60 degrees or more without consolidating the irradiation angles, the incident light is refracted and emitted from the outer wall surface 22b of the lens 16 as shown in the present embodiment. A lens having a function to be used is preferable. That is, according to the illuminating device and the illuminating lens according to the present embodiment, the illuminating lens capable of improving the use efficiency of the light emitted to the irradiation region and reducing unpleasant glare, and the illuminating device including the same Can be provided.

In addition, in this embodiment, although several LED was used as a light source, it is good also as a structure using single LED. When a plurality of LEDs are used, these LEDs may be arranged linearly, in an annular shape, or arranged in a lattice shape.

Next, lighting devices according to other embodiments 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. 6 is an enlarged cross-sectional view showing one lens unit of the illumination device 10 according to the second embodiment. The basic configuration of the illumination device 10 is the same as that of the first embodiment, and the shape of the illumination lens 16 is partially different. In the second embodiment, the inner upper surface 24a of the lens 16 is not a flat surface, but forms a convex portion 26 protruding slightly toward the outer upper surface 22a.

According to this configuration, the diverging action of the light beam passing through the convex portion 26 can be strengthened, and as shown in FIG. 7, the luminous intensity distribution is such that the luminous intensity at the angle θ of 45 degrees is the maximum luminous intensity. That is, the lens 16 is formed so that the angle θ at which the maximum luminous intensity is between 20 and 60 degrees, and the illuminance on the floor surface or the desk surface to be irradiated is shifted from the position directly below the lighting device 10. However, it is possible to obtain a substantially uniform illuminance.

The illuminance distribution on the surface to be irradiated by a normal LED light source is a light intensity distribution proportional to cos θ, so that the central light intensity is large and the illuminance at the center of the surface to be irradiated is large due to the short irradiation distance. The result is a non-uniform illumination distribution that gets darker. On the other hand, according to the illuminating device 10 of this embodiment, since light distribution becomes the light intensity distribution mentioned above, this illuminance distribution can be compensated and a substantially uniform illuminance distribution can be obtained.

Also in the second embodiment, the light use efficiency and the glare reduction are the same as in the first embodiment because the light emitted in the lateral direction is greatly reduced as in the first embodiment. It goes without saying that the effect of can be obtained.

In the second embodiment, the inner upper surface 24a of the lens 16 has a convex shape that is convex upward. Alternatively, the outer upper surface 22a of the lens 16 may have a concave shape that is recessed toward the LED 14 side. The divergent action can be strengthened. Therefore, as in the third embodiment shown in FIG. 8, the inner upper surface 24a of the illumination lens 16 may be a flat surface and the outer upper surface 22a may be recessed.

As in the fourth embodiment shown in FIG. 9, the inner wall surface 24 b of the illumination lens 16 is not limited to a truncated cone-shaped tapered surface, and may be a curved surface.
In the third and fourth embodiments described above, it is possible to obtain the same operational effects as those of the first embodiment described above.

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, 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. In addition, in order to blur color unevenness and luminance unevenness due to the lens, the entire lens surface or at least a part of it may be subjected to embossing or knurling. Further, a thin milky white may be obtained by mixing a slight diffusion filler into the resin material forming the lens cover and the illumination lens. However, if the lens is densely formed with wrinkles or knurls, or if the lens is dark milky white, the lens effect deteriorates, so it is necessary to keep it to the minimum necessary. The substrate and the lens cover of the lighting device are not limited to a circular shape, and various shapes such as a rectangular shape, a polygonal shape, and an elliptical shape can be selected.

Claims (10)

1. A light source and an illumination lens that receives light emitted from the light source, controls the incident light, and emits the light toward the irradiated surface,
   The illumination lens has a recess formed in a lower central portion for receiving light from the light source, an outer upper surface for emitting the incident light, and an outer wall surface, and the recess has an inner upper surface and an inner surface. At least part of the light incident on the inner wall surface from the light source is mainly refracted and emitted upward from the outer wall surface, and the light incident from the inner upper surface is mainly An illumination device that emits light from an outer upper surface.
2. The illumination lens refracts a part of a light beam traveling in the lateral direction at least θ of 60 degrees or more when θ is an angle perpendicular to the light source, and θ is within 60 degrees. The illumination device according to claim 1, wherein the illumination device emits light.
3. When the angle perpendicular to the light source is θ, the illumination lens emits light from the outer upper surface so that the angle θ giving the maximum luminous intensity is an oblique direction in the range of 20 degrees to 60 degrees. The illuminating device according to claim 2, wherein the illuminating device diffuses.
4. The lighting device according to any one of claims 1 to 3, wherein at least a part of the inner upper surface is formed in a convex shape toward the outer upper surface.
5. The lighting device according to any one of claims 1 to 3, wherein at least a part of the outer upper surface is formed in a concave shape.
6. 4. The illumination device according to claim 1, wherein a texture is formed on at least a part of the surface of the illumination lens.
7. 4. The illumination device according to claim 1, wherein a knurling process is applied to at least a part of the surface of the illumination lens.
8. 4. The illumination device according to claim 1, wherein the illumination lens contains a scattering filler at least in part.
9. An illumination lens that receives light emitted from a light source, controls the incident light, and emits the light toward an irradiated surface.
   A recess formed in the lower central portion for receiving light from the light source, an outer upper surface for emitting the incident light, and an outer wall surface, the recess having an inner upper surface and an inner surface facing the light source At least part of the light incident on the inner wall surface from the light source is mainly refracted and emitted upward from the outer wall surface, and the light incident from the inner upper surface is mainly An illumination lens that emits light from an outer upper surface.
10. When θ is an angle with respect to a direction perpendicular to the light source, at least θ is partially refracted within 60 degrees in the lateral direction where θ is 60 degrees or more and emitted from the outer wall surface. The illumination lens according to claim 9.

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