JP2018085251A - Illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illuminating device downsized by shortening a length in an optical axis direction with no need for complex design.SOLUTION: In an illuminating device, a light source, a first linear Fresnel lens, and a second linear Fresnel lens are arranged in this order along an optical axis. A plurality of first parallel straight prisms provided on a surface of the first linear Fresnel lens intersect with a plurality of second parallel straight prisms provided on a surface of the second linear Fresnel lens, at a predetermined angle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an illumination device capable of controlling light distribution.

The illuminating device generally has a light distribution characteristic such that the luminous intensity of the front surface of the light emitting surface is the largest and the luminous intensity decreases as the angle from the front surface increases. And in the illuminating device which has such a light distribution characteristic, the to-be-illuminated surface in the position away from the illuminating device (For example, when using such an illuminating device attached to a ceiling as room lighting, it is a floor surface) There is a problem that the illuminance at is large only under the lighting device and decreases rapidly as it goes to the periphery.
Conventionally, in order to avoid this problem and achieve uniform illuminance in a relatively wide area on the surface to be illuminated, it is known that the light distribution characteristic of the lighting device is a batwing shape (for example, Patent Documents). 1).
Patent Document 2 proposes an illumination device that controls light distribution by changing the distance between a light source and a lens. In this illumination device, when the light source is arranged at a position smaller than the focal length f of the Fresnel lens, the emitted light travels in a direction parallel to the optical axis and a direction inclined inward with respect to the optical axis. When arranged at a position larger than the focal length f of the Fresnel lens, the emitted light travels in a direction parallel to the optical axis and a direction inclined outward with respect to the optical axis.

JP 2012-230811 A JP 2002-221605 A

In the illumination device described in Patent Document 1 described above, a light distribution control member having a plurality of prisms provided on the surface is used. However, the surface shape includes an inclined surface and a flat surface, and a complicated design is required. there were.
In the illuminating device described in Patent Document 2 described above, the distance between the light source and the lens is changed for light distribution control, and thus the illuminating device becomes large in the optical axis direction.
In view of the above, an object of the present invention is to solve the above-described problems, to provide a lighting device that is not required to have a complicated design and is reduced in size by reducing the distance in the optical axis direction.

The gist of the present invention is as follows.
The lighting device of the present invention is
A light source;
A first linear Fresnel lens;
A second linear Fresnel lens;
Are arranged in this order along the optical axis,
A plurality of parallel linear first prisms provided on the surface of the first linear Fresnel lens; and a plurality of parallel linear second prisms provided on the surface of the second linear Fresnel lens; Intersect at a certain angle,
It is characterized by that.

In the lighting device of the present invention,
The predetermined angle is greater than 0 degree and 90 degrees or less.
It is preferable.

In the lighting device of the present invention,
The light emitted from the first linear Fresnel lens is inclined 5 degrees with respect to the optical axis,
The outgoing light from the second linear Fresnel lens is parallel to the optical axis.
It is preferable.

1 shows a lighting device according to a first embodiment of the present invention. The light distribution of the emitted light from an illuminating device is shown. (A) shows the structure which rotated the 2nd linear Fresnel lens of the illuminating device which concerns on 1st Embodiment of this invention by 30 degree | times, (b) shows the light distribution of the emitted light from an illuminating device. . (A) shows the structure which rotated the 2nd linear Fresnel lens of the illuminating device which concerns on 1st Embodiment of this invention 45 degree | times, (b) shows the light distribution of the emitted light from an illuminating device. . The illuminating device which concerns on 2nd Embodiment of this invention is shown. In the illuminating device which concerns on 2nd Embodiment of this invention, the light distribution is shown when the rotation angle of the second linear Fresnel lens is changed. In the illuminating device which concerns on 3rd Embodiment of this invention, the light distribution is shown when the rotation angle of the second linear Fresnel lens is changed. The light distribution of the emitted light from the illuminating device which concerns on a reference example is shown.

Hereinafter, an illuminating device of the present invention will be described in detail with reference to the drawings, illustrating an embodiment thereof.
FIG. 1A is a perspective view of a lighting device according to the first embodiment of the present invention, FIG. 1B is a zx sectional view thereof, and FIG. 1C is a yz sectional view thereof.
In the illumination device 100, a light source 5 such as an LED, a first linear Fresnel lens 10, and a second linear Fresnel lens 20 are arranged in this order along the optical axis (z direction).
On the surface of the first linear Fresnel lens 10 on the light source 5 side, a plurality of parallel straight first prisms 11 are provided along the y direction, and the first linear Fresnel lens 20 has a first linear Fresnel lens 20. On the surface on the lens 10 side, a plurality of parallel linear second prisms 21 are provided along the x direction. That is, the first prism 11 and the second prism 21 intersect at an angle of 90 degrees. In this case, the first linear Fresnel lens 10 emits light spreading in the x direction parallel to the optical axis, and the second linear Fresnel lens 20 emits light spreading in the y direction parallel to the optical axis. As a result, the light emitted from the illumination device 100 has a light distribution as shown in FIG.
FIG. 2 shows the light distribution in the x direction (solid line) and the y direction (broken line) of the light emitted from the illumination device 100. Light distribution is controlled to be less than about ± 15 degrees in both the x direction and the y direction.
In the drawings, the Fresnel lens (0 degree light distribution) means that light emitted from the Fresnel lens is parallel to the optical axis (tilted at 0 degree with respect to the optical axis).

  Next, as shown in FIG. 3A, only the second linear Fresnel lens 20 is rotated 30 degrees in the xy plane from the state of FIG. That is, the first prism 11 and the second prism 21 intersect at an angle of 60 degrees. In this case, the light emitted from the illumination device 100 has a light distribution as shown in FIG. FIG. 3B shows that the light distribution spreads to about ± 30 degrees in both the x direction and the y direction, and the light distribution in the y direction has a shape close to a trapezoid.

  Next, as shown in FIG. 4A, only the second linear Fresnel lens 20 is rotated 45 degrees in the xy plane from the state of FIG. That is, the first prism 11 and the second prism 21 intersect at an angle of 45 degrees. In this case, the light emitted from the illumination device 100 has a light distribution as shown in FIG. From FIG. 4B, in the x direction, the light distribution spreads to about ± 30 degrees, the peak is divided into two, and the light distribution in the y direction spreads to more than ± 40 degrees and has a shape close to a trapezoid. I understand that there is.

As shown in FIGS. 1 to 4, it can be seen that the light distribution of the emitted light from the illumination device 100 changes greatly only by changing the crossing angle between the first prism 11 and the second prism 21. In this way, a desired light distribution can be achieved simply by rotating the second linear Fresnel lens 20, so that a complicated design is not necessary. Moreover, since it is not necessary to move the second linear Fresnel lens 20 in the optical axis direction, a miniaturized illumination device can be provided. However, when at least one of the first linear Fresnel lens 10 and the second linear Fresnel lens 20 is moved in the optical axis direction, an effect that the surface distribution of the emitted light can be made uniform is also produced.
In the first embodiment, only the second linear Fresnel lens 20 is rotated. However, only the first linear Fresnel lens 10 may be rotated, or the first linear Fresnel lens 10 and the second linear Fresnel lens 10 may be rotated. Both Fresnel lenses 20 may be rotated. Further, in the first embodiment, the first prism 11 is provided on the surface of the first linear Fresnel lens 10 on the light source 5 side, and the second prism 21 is the first linear Fresnel lens 20 first. Although provided on the surface on the linear Fresnel lens 10 side, each may be provided on the opposite surface.

FIG. 5 is a cross-sectional view of a lighting apparatus according to the second embodiment of the present invention.
The lighting device 200 is the same as the lighting device 100 except that the first linear Fresnel lenses 10a and 10b are used. In the first linear Fresnel lens 10 of the illuminating device 100, light spreading in the x direction is emitted in parallel to the optical axis, whereas in the first linear Fresnel lens 10a shown in FIG. In the first linear Fresnel lens 10b shown in FIG. 5B, the light spreading in the x direction is inclined 5 degrees inward with respect to the optical axis. Inclined outward by 5 degrees and emitted. In the drawing, the Fresnel lens inclined at 5 degrees inward and outward with respect to the optical axis is described as a Fresnel lens (5-degree light distribution).
The second linear Fresnel lens 20 emits light spreading in the y direction in parallel to the optical axis, as in the case of the illumination device 100. Therefore, it is described as a Fresnel lens (0 degree light distribution) in the drawings.
As a result, the light emitted from the illumination device 200 has a light distribution as shown in FIG.

In FIG. 6A, since the first prism 11 is provided in the y direction and the second prism 21 is provided in the x direction, the first prism 11 and the second prism 21 are 90 degrees. The light distribution in a state of intersecting at an angle is shown. In the x direction, the first linear Fresnel lens is distributed to about ± 20 degrees due to the 5 degree light distribution, and in the y direction, the second linear Fresnel lens is distributed to about ± 15 degrees due to the 0 degree light distribution. The light is controlled.
In FIG. 6B, as in FIG. 3A, the first prism 11 is provided in the y direction, and the second prism 21 is provided in a direction inclined by 30 degrees with respect to the x direction. The light distribution in a state where the first prism 11 and the second prism 21 intersect at an angle of 60 degrees is shown. The light distribution spreads to about ± 30 degrees in both the x direction and the y direction. Further, the light distribution in the x direction has a shape close to a trapezoid, and the light distribution in the y direction has a shape in which the peak is divided into two.
In FIG. 6C, as in FIG. 4A, the first prism 11 is provided in the y direction, and the second prism 21 is provided in a direction inclined by 45 degrees with respect to the x direction. The light distribution in a state where the first prism 11 and the second prism 21 intersect at an angle of 45 degrees is shown. In the x direction, the light distribution spreads up to about ± 30 degrees and the peak is divided into two large parts. In the y direction, the light distribution spreads up to about ± 60 degrees and the peak is divided into two parts.
As shown in FIGS. 6B and 6C, the first linear Fresnel lens 10a, 10b is a 5-degree light distribution lens, and the second linear Fresnel lens 20 is rotated, so that The light distribution characteristic can be a shape close to a batwing shape.

Although not shown, in the illumination device according to the third embodiment of the present invention, the first linear Fresnel lens tilts the light spreading in the x direction inward or outward by 5 degrees with respect to the optical axis. The second linear Fresnel lens tilts the light spreading in the y direction inward or outward by 5 degrees with respect to the optical axis. As a result, the light emitted from the illumination device has a light distribution as shown in FIG.
In FIG. 7A, since the first prism is provided in the y direction and the second prism is provided in the x direction, the first prism and the second prism intersect at an angle of 90 degrees. The light distribution of the state is shown. The light distribution spreads to about ± 20 degrees in both the x direction and the y direction. Further, the light distribution in the x direction has a shape close to a trapezoid, and the light distribution in the y direction has a shape in which the peak is divided into two.
In FIG. 7B, as in FIG. 3A, the first prism is provided in the y direction and the second prism is provided in a direction inclined by 30 degrees with respect to the x direction. The light distribution is shown in a state where the first prism and the second prism intersect at an angle of 60 degrees. The light distribution spreads to about ± 40 degrees in both the x direction and the y direction. The light distribution in the x direction has a shape with two peaks, and the light distribution in the y direction has a shape close to a trapezoid.
In FIG. 7C, as in FIG. 4A, the first prism is provided in the y direction and the second prism is provided in a direction inclined by 45 degrees with respect to the x direction. The light distribution is shown in a state where the first prism and the second prism intersect at an angle of 45 degrees. The light distribution spreads to about ± 40 degrees in both the x direction and the y direction. The light distribution in the x direction has a shape with two peaks, and the light distribution in the y direction has a shape close to a trapezoid.

  In addition, in 2nd Embodiment and 3rd Embodiment mentioned above, the emitted light from a linear Fresnel lens inclined 5 degree | times with respect to the optical axis, However, 5 degree | times is an example and it makes it an arbitrary inclination angle. Can be set.

FIG. 8 shows a light distribution of emitted light when a lens (prism sheet) in which a uniform prism is formed instead of a linear Fresnel lens is used as a reference example. In the illumination device according to the reference example, a light source, a first prism sheet having a plurality of parallel linear first uniform prisms formed on the surface, and a plurality of parallel linear second uniform prisms formed on the surface The second prism sheet thus formed is arranged in this order along the optical axis.
In FIG. 8A, since the first uniform prism is provided in the y direction and the second uniform prism is provided in the x direction, the first uniform prism and the second uniform prism are 90 degrees. The light distribution in a state of intersecting at an angle is shown. The transmitted light is zero in both the x direction and the y direction.
In FIG. 8B, the first uniform prism is provided in a direction inclined by 45 degrees with respect to the x direction, and the second uniform prism is provided in a direction inclined by 135 degrees with respect to the x direction. The light distribution is shown in a state where the first uniform prism and the second uniform prism intersect at an angle of 90 degrees. In both the x-direction and the y-direction, the transmitted light within ± 20 degrees becomes zero, and the intensity decreases as the absolute value of the angle increases in a range larger than ± 20 degrees.
In FIG. 8C, since the first uniform prism is provided in the y direction and the second uniform prism is provided in a direction inclined by 30 degrees with respect to the x direction, the first uniform prism and the second uniform prism are provided. A light distribution in a state where the uniform prism intersects at an angle of 60 degrees. In the x direction, the transmitted light within ± 25 degrees becomes zero, a peak appears at about ± 45 degrees, and the intensity decreases as the absolute value of the angle increases in the range exceeding ± 45 degrees. In the y direction, the transmitted light within ± 10 degrees becomes zero, the range from ± 10 degrees to ± 50 degrees is substantially constant, and in the range exceeding 50 degrees, the intensity decreases as the absolute value of the angle increases. Yes.
In FIG. 8D, since the first uniform prism is provided in the y direction and the second uniform prism is provided in a direction inclined by 45 degrees with respect to the x direction, the first uniform prism and the second uniform prism are provided. The light distribution in a state in which the uniform prism intersects at an angle of 45 degrees. In both the x direction and the y direction, the transmitted light within ± 15 degrees is zero. In the x-direction, the intensity decreases as the absolute value of the angle increases in the range of ± 15 degrees to ± 40 degrees, increases after the increase of ± 40 degrees, and then increases as the absolute value of the angle increases within the range of ± 40 degrees. The strength is decreasing. In the y direction, the intensity decreases as the absolute value of the angle increases in the range exceeding ± 15 degrees.
Unlike the case where a linear Fresnel lens is used, when a prism sheet is used, the transmitted light near 0 degrees becomes 0, and a light distribution effective as a general lighting device cannot be achieved.

DESCRIPTION OF SYMBOLS 5 Light source 10, 10a, 10b 1st linear Fresnel lens 11 1st prism 20 2nd linear Fresnel lens 21 2nd prism 100, 200 Illuminating device

Claims (3)

A light source;
A first linear Fresnel lens;
A second linear Fresnel lens;
Are arranged in this order along the optical axis,
A plurality of parallel linear first prisms provided on the surface of the first linear Fresnel lens; and a plurality of parallel linear second prisms provided on the surface of the second linear Fresnel lens; Intersect at a certain angle,
A lighting device characterized by that. The predetermined angle is greater than 0 degree and 90 degrees or less.
The lighting device according to claim 1. The light emitted from the first linear Fresnel lens is inclined 5 degrees with respect to the optical axis,
The outgoing light from the second linear Fresnel lens is parallel to the optical axis.
The illumination device according to claim 1 or 2.

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