JP2022101353A - Lighting device and method for manufacturing lighting device - Google Patents

Abstract

To provide a lighting device in which controllable light can be increased.SOLUTION: A lighting device includes: a first light guide body 10 having prism surfaces on which a plurality of concave prisms 11 each having a concave shape; a second light guide body 20 having prism surfaces on which a plurality of convex prisms 21 each having a convex shape; and a light source 30 emitting light incident to at least one end surface of the first light guide body 10 and the second light guide body 20. The first light guide body 10 and the second light guide body 20 are arranged so that the plurality of concave prisms 11 and the plurality of convex prisms 21 are engaged via an air layer 2.SELECTED DRAWING: Figure 1C

Description

The present invention relates to a lighting device and a method for manufacturing the lighting device, and more particularly to a lighting device using a light guide and a method for manufacturing the lighting device.

Conventionally, an edge light type lighting device is known as a lighting device using a light guide. The edge light type lighting device includes a light guide plate which is a light guide body and a light source arranged so as to face the end surface of the light guide plate.

As a lighting device of this type, for example, in Patent Document 1, a plate-shaped light guide plate having a first main surface which is a prism surface on which a plurality of concave prisms are formed is arranged so as to face the end surface of the light guide plate. A surface light source device including a light source is disclosed.

In such a lighting device, the light emitted from the light source is incident from the end surface of the light guide plate to guide the inside of the light guide plate, is reflected by a plurality of prisms, and is turned back to the first main surface (prism surface). It emits light from the second main surface to the outside of the light guide plate.

Japanese Unexamined Patent Publication No. 11-21609

In a lighting device using a light guide body in which a plurality of prisms are formed on the first main surface, the light emitted from the second main surface, which is the light extraction surface, can be emitted to the outside by adjusting the shape and arrangement of the prisms. The light distribution can be controlled. For example, the light distribution angle of the light emitted from the light extraction surface can be controlled by adjusting the base angle of the prism or the like.

However, in the conventional lighting device using such a light guide, light leaks from the first main surface (prism surface) on which the prism is formed. That is, a part of the light emitted from the light source and incident on the light guide becomes leaky light and leaks from the prism surface to the outside of the light guide. For example, nearly half of the light incident on the light guide may be leaked light. Moreover, this leaked light is difficult to control.

As described above, in the conventional lighting device using a light guide body in which a plurality of prisms are formed, there is a problem that a large amount of light that is difficult to control is included in the light emitted from the light guide body.

The present invention has been made to solve such a problem, and even when a light guide body having a plurality of prisms formed is used, the illumination that can control a large amount of light can be increased. It is an object of the present invention to provide an apparatus and a method for manufacturing the apparatus.

In order to achieve the above object, one aspect of the lighting device according to the present invention is a first light guide body having a prism surface on which a plurality of concave prisms each having a concave shape are formed, and a plurality of light guide bodies each having a convex shape. A second light guide having a prism surface on which a convex prism is formed, and a light source that emits light incident on at least one end surface of the first light guide and the second light guide are provided. The 1 light guide body and the second light guide body are arranged so that the plurality of concave prisms and the plurality of convex prisms are fitted with each other via an air layer.

Further, one aspect of the method for manufacturing a lighting device according to the present invention is a first light guide body each having a prism surface on which a plurality of concave first prisms are formed, and a plurality of second light guides each having a convex shape. A method for manufacturing a lighting device including a second light guide body having a prism surface on which a prism is formed, wherein the first light guide body and the second light guide body are manufactured by a stamper manufactured from the same master. Will be done.

It is possible to obtain a lighting device that can increase the amount of light that can be controlled while being a lighting device that uses a light guide body in which a plurality of prisms are formed.

FIG. 1A is a perspective view of the lighting device according to the embodiment. FIG. 1B is a cross-sectional view of an embodiment illuminating device when cut along the IB-IB line of FIG. 1A. FIG. 1C is a cross-sectional view of the illuminating device according to the embodiment when cutting along the IC-IC line of FIG. 1A. FIG. 2A is a perspective view of a part of each of the first light guide body and the second light guide body in the lighting device according to the embodiment when viewed from below. FIG. 2B is a perspective view of a part of each of the first light guide body and the second light guide body in the lighting device according to the embodiment when viewed from the side. FIG. 3 is a diagram for explaining a method of manufacturing the first light guide body and the second light guide body. FIG. 4A is a diagram showing a configuration of a lighting device of a comparative example and a light distribution image. FIG. 4B is a diagram for explaining the optical action of the lighting device of the comparative example. FIG. 4C is a diagram showing the light distribution of the lighting device of the comparative example. FIG. 5A is a diagram showing a configuration of a lighting device and a light distribution image according to an embodiment. FIG. 5B is a diagram for explaining the optical action of the lighting device according to the embodiment. FIG. 5C is a diagram showing a light distribution of the lighting device according to the embodiment. FIG. 6 is a diagram showing the relationship between the base angle of the concave prism and the convex prism, the luminous flux of the front light, the luminous flux of the back light, the efficiency of the fixture, and the light distribution in the lighting device according to the embodiment. FIG. 7 is a diagram showing the relationship between the thickness of the second light guide body, the luminous flux of the front light, the luminous flux of the back light, the efficiency of the fixture, and the light distribution in the lighting device according to the embodiment. FIG. 8 is a diagram showing the relationship between the thickness of the air layer between the concave prism and the convex prism, the luminous flux of the front light, the luminous flux of the back light, the efficiency of the fixture, and the light distribution in the lighting device according to the embodiment. Is. FIG. 9 is a cross-sectional view showing the configuration of the lighting device according to the first modification. FIG. 10 is a cross-sectional view showing the configuration of the lighting device according to the modified example 2. FIG. 11 is a cross-sectional view showing the configuration of the lighting device according to the modified example 3. FIG. 12 is a diagram showing a luminous flux of front light, a luminous flux of back light, an instrument efficiency, and a light distribution distribution in each of the lighting devices of the embodiment, the modified example 1, the modified example 2, and the modified example 3. FIG. 13 is a cross-sectional view showing the configuration of the lighting device according to the modified example 4. FIG. 14A is a perspective view of the lighting device according to the modified example 5. FIG. 14B is a cross-sectional view of the illuminating device according to the modified example 5 when cut along the XIVB-XIVB line of FIG. 14A. FIG. 14C is a cross-sectional view of the illuminating device according to the modified example 5 when cut along the XIVC-XIVC line of FIG. 14A. FIG. 15 is a diagram showing a state in which the gap between the first light guide body and the second light guide body is increased in the central portion in the lighting device according to the embodiment. FIG. 16 is a diagram for explaining the lighting device according to the modified example 6.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, all of the embodiments described below show a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps (steps), and the like shown in the following embodiments are examples and do not limit the present invention. Therefore, among the components in the following embodiments, the components not described in the independent claims are described as arbitrary components.

Each figure is a schematic diagram and is not necessarily exactly illustrated. Further, in each figure, the same reference numerals may be given to substantially the same configurations, and duplicate explanations may be omitted or simplified. In each figure, the X-axis, the Y-axis, and the Z-axis represent the three axes of the three-dimensional Cartesian coordinate system. The X-axis and the Y-axis are orthogonal to each other and both are orthogonal to the Z-axis.

(Embodiment)
First, the configuration of the lighting device 1 according to the embodiment will be described with reference to FIGS. 1A, 1B, 1C, 2A and 2B. FIG. 1A is a perspective view of the lighting device 1 according to the embodiment. FIG. 1B is a cross-sectional view of the illuminating device 1 when cut along the IB-IB line of FIG. 1A. FIG. 1C is a cross-sectional view of the illuminating device 1 when cut along the IC-IC line of FIG. 1A. 2A and 2B are perspective views showing a part of each of the first light guide body 10 and the second light guide body 20 in the lighting device 1. In FIGS. 2A and 2B, the first light guide body 10 and the first light guide body 10 and the shape of the convex prism 21 of the second light guide body 20 can be easily seen so that the shape of the concave prism 11 of the first light guide body 10 and the shape of the convex prism 21 of the second light guide body 20 can be easily seen. 2 The light guide body 20 is shown in a state of being separated from the actual one.

As shown in FIGS. 1A to 1C, the lighting device 1 includes a first light guide body 10, a second light guide body 20, a light source 30, and a holding member 40.

The first light guide body 10 and the second light guide body 20 are optical members having a function of guiding light. In the present embodiment, the first light guide body 10 and the second light guide body 20 are plate-shaped light guide plates. Specifically, the first light guide body 10 and the second light guide body 20 are light guide plates having a rectangular shape in a plan view and a flat plate shape. As an example, the thickness of each of the first light guide body 10 and the second light guide body 20 is about several mm to several cm, but is not limited to this. The thickness of the first light guide body 10 and the thickness of the second light guide body 20 may be the same or different.

The first light guide body 10 and the second light guide body 20 are translucent members having translucency at least in the visible light region. The transmittance of the first light guide body 10 and the second light guide body 20 is preferably high, and is preferably at least 50% or more. Specifically, the first light guide body 10 and the second light guide body 20 are preferably transparent to visible light. The transparent first light guide body 10 and the transparent second light guide body 20 have a high transmittance so that the other side can be seen through. In this case, the transmittance of each of the transparent first light guide body 10 and the transparent second light guide body 20 with respect to visible light is 70% or more, preferably 80% or more, and more preferably 90% or more. The first light guide body 10 and the second light guide body 20 may have translucency not only in the visible light region but also in the near infrared region. That is, the first light guide body 10 and the second light guide body 20 may have translucency in the visible light region and the near infrared region.

The first light guide body 10 and the second light guide body 20 are made of a translucent material. The first light guide body 10 and the second light guide body 20 are transparent substrates that are transparent to visible light, such as a transparent resin substrate made of a transparent resin material or a glass substrate made of a transparent glass material. .. As the transparent resin substrate, an acrylic substrate made of an acrylic resin or a polycarbonate substrate made of a polycarbonate resin can be used. The transparent resin substrate may be a rigid substrate having no flexibility or a flexible substrate having flexibility. In this embodiment, a rigid and transparent acrylic substrate is used as the first light guide body 10 and the second light guide body 20.

The first light guide body 10 includes a first main surface 10a, a second main surface 10b facing back to the first main surface 10a, a first end surface 10c, and a second end surface 10d facing back to the first end surface 10c. Have.

The first main surface 10a and the second main surface 10b are surfaces that can be seen when the flat plate-shaped first light guide body 10 is viewed in a plan view. Further, the first main surface 10a and the second main surface 10b face each other in the thickness direction of the flat plate-shaped first light guide body 10. In the present embodiment, the first main surface 10a and the second main surface 10b are each flat and substantially parallel. Since the shape of the first light guide body 10 in a plan view is substantially rectangular, the shapes of the first main surface 10a and the second main surface 10b are substantially rectangular.

As shown in FIG. 1C, a plurality of concave prisms 11 each having a concave shape are formed on the first main surface 10a. That is, the first main surface 10a is a concave prism surface on which a plurality of concave prisms 11 are formed. As described above, the first light guide body 10 is a concave prism light guide plate having a plurality of concave prisms 11.

In the present embodiment, the plurality of concave prisms 11 have a function of reflecting light that guides the inside of the first light guide body 10. Therefore, the concave prism 11 has a reflecting surface (light control surface) that reflects a part of the light that guides the inside of the first light guide body 10 toward the second main surface 10b side.

Each of the plurality of concave prisms 11 has an axisymmetric concave shape. As an example, each of the plurality of concave prisms 11 has an axisymmetric conical shape or a hemispherical shape. That is, in this case, each concave prism 11 is a concave portion having a shape in which a part of the plane of the first main surface 10a is hollowed out in a conical shape or a hemispherical shape. As shown in FIGS. 2A and 2B, in the present embodiment, each of the plurality of concave prisms 11 has an axisymmetric conical shape. Therefore, as shown in FIG. 1C, the cross-sectional shape of each concave prism 11 is an isosceles triangle when cut in a plane parallel to the thickness direction of the first light guide body 10. The inner surface of the conical concave prism 11 is a reflective surface (light control surface) that reflects a part of the light that guides the inside of the first light guide body 10 toward the second main surface 10b.

The plurality of concave prisms 11 configured in this way are arranged two-dimensionally on the first main surface 10a. Specifically, when viewed from the main surface vertical direction of the first main surface 10a, the concave prism 11 has a first direction toward the other from one of the first end surface 10c and the second end surface 10d (in the present embodiment). A plurality of arrangements are made along the X-axis direction), and a plurality of arrangements are made along the second direction (Y-axis direction in the present embodiment) substantially orthogonal to the first direction. The plurality of concave prisms 11 may be formed over the entire first main surface 10a, but may be partially formed.

The second main surface 10b is a light emitting surface (light emitting surface) in which light incident on the first light guide body 10 is emitted to the outside of the first light guide body 10. Therefore, the second main surface 10b is a light emitting surface that emits pseudo light when the light that guides the inside of the first light guide body 10 is emitted to the outside. That is, the second main surface 10b is a light extraction surface for extracting light that guides the inside of the first light guide body 10, and is a front surface (front surface) of the lighting device 1. In the present embodiment, the second main surface 10b is a flat surface on which a prism is not formed.

Each of the first end surface 10c and the second end surface 10d is one of a plurality of side surfaces of the first light guide body 10. In the present embodiment, since the first light guide body 10 is a light guide plate having a rectangular shape in a plan view and a flat plate shape, each of the first end surface 10c and the second end surface 10d is one of four side surfaces. It has a long rectangular shape. The first end surface 10c and the second end surface 10d face each other in a direction orthogonal to the thickness direction of the first light guide body 10. That is, the second end surface 10d is located on the opposite side of the first end surface 10c. As an example, the first end surface 10c and the second end surface 10d are flat surfaces and are substantially parallel to each other. The first end surface 10c and the second end surface 10d are not limited to flat surfaces, but may be curved surfaces curved in a concave or convex shape. Further, the first end surface 10c and the second end surface 10d may be inclined surfaces.

In the present embodiment, the first end surface 10c is a light incident surface (light incident surface) on which light emitted from the light source 30 is incident. Specifically, the first end surface 10c faces the light source 30. That is, the first end surface 10c is the surface on the light source 30 side, and the second end surface 10d is the surface on the opposite side to the light source 30 side.

Next, the second light guide body 20 will be described. The second light guide body 20 includes a third main surface 20a, a fourth main surface 20b facing back to the third main surface 20a, a third end surface 20c, and a fourth end surface 20d facing back to the third end surface 20c. Have.

The third main surface 20a and the fourth main surface 20b are surfaces that can be seen when the flat plate-shaped second light guide body 20 is viewed in a plan view. Further, the third main surface 20a and the fourth main surface 20b face each other in the thickness direction of the flat plate-shaped second light guide body 20. In the present embodiment, the third main surface 20a and the fourth main surface 20b are each flat and substantially parallel. Since the shape of the second light guide body 20 in a plan view is substantially rectangular, the shapes of the third main surface 20a and the fourth main surface 20b are substantially rectangular.

As shown in FIG. 1C, the third main surface 20a of the second light guide body 20 is a surface on the side of the first light guide body 10. That is, the third main surface 20a of the second light guide body 20 faces the first main surface 10a of the first light guide body 10. On the other hand, the fourth main surface 20b of the second light guide body 20 is a surface opposite to the first light guide body 10 side. In the present embodiment, since the second light guide body 20 is a light guide plate having the same size as the first light guide body 10 as a whole, the third main surface 20a and the fourth main surface of the second light guide body 20 Each of 20b and each of the first main surface 10a and the second main surface 10b of the first light guide body 10 have the same size and shape, but are not limited to this. That is, each of the third main surface 20a and the fourth main surface 20b of the second light guide body 20 and each of the first main surface 10a and the second main surface 10b of the first light guide body 10 have different shapes or different shapes. It may be of a size.

A plurality of convex prisms 21 each having a convex shape are formed on the third main surface 20a of the second light guide body 20. That is, the third main surface 20a is a convex prism surface on which a plurality of convex prisms 21 are formed. As described above, the second light guide body 20 is a convex prism light guide plate having a plurality of convex prisms 21. The fourth main surface 20b of the second light guide body 20 is the back surface (back surface) of the lighting device 1. In the present embodiment, the fourth main surface 20b is a flat surface on which a prism is not formed.

Each of the plurality of convex prisms 21 has an axisymmetric convex shape. As an example, each of the plurality of convex prisms 21 has an axisymmetric conical shape or a hemispherical shape. That is, in this case, each convex prism 21 is a convex portion having a shape protruding from the third main surface 20a in a conical shape or a hemispherical shape. As shown in FIGS. 2A and 2B, in the present embodiment, each of the plurality of convex prisms 21 has an axisymmetric conical shape. Therefore, as shown in FIG. 1C, the cross-sectional shape of each convex prism 21 is an isosceles triangle when cut in a plane parallel to the thickness direction of the second light guide body 20.

The plurality of convex prisms 21 configured in this way are arranged two-dimensionally on the third main surface 20a. Specifically, when viewed from the main surface vertical direction of the third main surface 20a, the convex prism 21 has a first direction toward the other from one of the third end surface 20c and the fourth end surface 20d (in the present embodiment). A plurality of arrangements are made along the X-axis direction), and a plurality of arrangements are made along the second direction (Y-axis direction in the present embodiment) substantially orthogonal to the first direction.

There is a one-to-one correspondence with the plurality of convex prisms 21 of the second light guide body 20 and the plurality of concave prisms 11 of the first light guide body 10. Therefore, the plurality of convex prisms 21 of the second light guide body 20 and the plurality of concave prisms 11 of the first light guide body 10 have the same number and are formed at the same position.

Further, assuming that each convex prism 21 of the second light guide 20 and each concave prism 11 of the first light guide 10 are fitted together, the convex prism 21 and the concave prism 11 have a structure of being fitted to each other. .. In the present embodiment, the convex prism 21 and the concave prism 11 are completely fitted. Therefore, the first light guide body 10 and the second light guide body 20 have a surface shape in which the unevenness is substantially completely inverted, and the shape and size of each concave prism 11 of the first light guide body 10 , The shape and size of each convex prism 21 of the second light guide body 20 are the same.

Therefore, the skirt angle θ (first prism angle) of each concave prism 11 of the first light guide body 10 and the skirt angle θ (second prism angle) of each convex prism 21 of the second light guide body 20 are different from each other. It is the same. For example, the base angle θ of each of the concave prism 11 and the convex prism 21 is 10 ° or more and 70 ° or less, preferably 20 ° or more and 65 ° or less, but is not limited to this. The skirt angle θ is the base angle of an isosceles triangle when the concave prism 11 and the convex prism 21 have an axisymmetric conical shape. As an example, the base angle θ of each of the concave prism 11 and the convex prism 21 is 55 °. Further, the skirt angle θ of the concave prism 11 and the skirt angle θ of the convex prism 21 are preferably the same, but may be different.

Each of the third end surface 20c and the fourth end surface 20d is one of a plurality of side surfaces of the second light guide body 20. The third end surface 20c is an end surface on the same side as the first end surface 10c of the first light guide body 10, and the fourth end surface 20d is an end surface on the same side as the second end surface 10d of the first light guide body 10. In the present embodiment, the second light guide body 20 is a light guide plate having a rectangular shape in a plan view and a flat plate shape like the first light guide body 10, so that the third end surface 20c and the fourth end surface 20d Each is one of four sides and has a long rectangular shape. The third end surface 20c and the fourth end surface 20d face each other in a direction orthogonal to the thickness direction of the second light guide body 20. That is, the fourth end surface 20d is located on the opposite side of the third end surface 20c. As an example, the third end surface 20c and the fourth end surface 20d are flat surfaces and are substantially parallel to each other. The third end surface 20c and the fourth end surface 20d are not limited to flat surfaces, but may be curved surfaces curved in a concave or convex shape. Further, the third end surface 20c and the fourth end surface 20d may be inclined surfaces.

The first light guide body 10 and the second light guide body 20 can be manufactured by the method shown in FIG. FIG. 3 is a diagram for explaining a method of manufacturing the first light guide body 10 and the second light guide body 20.

Specifically, as shown in FIG. 3A, first, a master substrate 100 as a master for manufacturing the first light guide body 10 and the second light guide body 20 is prepared.

Next, as shown in FIG. 3B, a father stamper 101 is manufactured as a first stamper based on the master substrate 100. The uneven shape of the father stamper 101 is an inverted shape of the uneven shape of the master substrate 100.

Next, as shown in FIG. 3 (c), a mother stamper 102 is manufactured as a second stamper based on the father stamper 101. The uneven shape of the mother stamper 102 is an inverted shape of the uneven shape of the father stamper 101. At this time, it is advisable to manufacture a plurality of mother stampers 102 from one father stamper 101.

Next, as shown in FIG. 3D, a sun stamper 103 is manufactured as a third stamper based on the mother stamper 102. The uneven shape of the sun stamper 103 is an inverted shape of the uneven shape of the mother stamper 102. At this time, it is advisable to manufacture a plurality of sun stampers 103 from one mother stamper 102.

The first light guide body 10 can be manufactured by a transfer method using a sun stamper 103. For example, the first light guide body 10 can be manufactured by injection molding using a mold incorporating the sun stamper 103. At this time, by using a plurality of sun stampers 103, a plurality of first light guide bodies 10 can be manufactured at the same time.

Further, the second light guide body 20 can be manufactured by a transfer method using a mother stamper 102. For example, the second light guide body 20 can be manufactured by injection molding using a mold incorporating the mother stamper 102. At this time, by using a plurality of mother stampers 102, a plurality of second light guide bodies 20 can be manufactured at the same time.

As described above, the first light guide body 10 and the second light guide body 20 are manufactured by a stamper manufactured from the same master. That is, the first light guide body 10 and the second light guide body 20 can be manufactured only by exchanging the stampers. In the present embodiment, the first light guide body 10 and the second light guide body 20 are manufactured by injection molding using a mold incorporating a stamper manufactured from the same master. The first light guide body 10 and the second light guide body 20 thus produced have a shape in which the concave prism 11 and the convex prism 21 are completely fitted.

In the lighting device 1, the first light guide body 10 and the second light guide body 20 thus produced are used. Specifically, as shown in FIGS. 1A and 1C, the first light guide body 10 and the second light guide body 20 are arranged so as to overlap each other. In this case, as shown in FIG. 1C, the first light guide body 10 and the second light guide body 20 are a plurality of concave prisms 11 of the first light guide body 10 and a plurality of convex prisms of the second light guide body 20. 21 is arranged so as to be fitted with the air layer 2 which is a minute gap. That is, the first light guide body 10 and the second light guide body 20 are a third main surface 10a which is a concave prism surface of the first light guide body 10 and a convex prism surface of the second light guide body 20. They are laminated so that the main surface 20a faces each other and the plurality of concave prisms 11 and the plurality of convex prisms 21 are not in contact with each other. As described above, the air layer 2 is interposed between the plurality of concave prisms 11 of the first light guide body 10 and the plurality of convex prisms 21 of the second light guide body 20. The first light guide body 10 and the second light guide body 20 laminated via the air layer 2 can also be regarded as one light guide member in the lighting device 1.

The thickness (air gap) of the air layer 2 between the first light guide body 10 and the second light guide body 20 is, for example, half or less of the depth of each of the plurality of concave prisms 11 or the plurality of convex prisms 21. It is less than half the height of each, but is not limited to this. The upper limit of the thickness of the air layer 2 is not particularly limited, but as an example, the thickness of the air layer 2 is 1 mm or less. Further, the lower limit of the thickness of the air layer 2 is not particularly limited, but as an example, the thickness of the air layer 2 is 1 μm or more. In the present embodiment, the thickness of the air layer 2 is 0.01 mm (10 μm). The thickness of the air layer 2 is substantially constant over the entire area of the first main surface 10a and the third main surface 20a.

The light emitted from the light source 30 is incident on the first light guide body 10 and the second light guide body 20 in the superposed state. The light source 30 emits light incident on at least one end surface of the first light guide body 10 and the second light guide body 20. As shown in FIGS. 1A and 1C, in the present embodiment, the light emitted from the light source 30 is incident on only the first light guide body 10 of the first light guide body 10 and the second light guide body 20. There is. That is, the light source 30 is arranged so that the light emitted from the light source 30 is incident only on the first end surface 10c of the first light guide body 10. Therefore, in the lighting device 1, the first light guide body 10 is the main light guide plate, and the second light guide body 20 is the sub light guide plate.

Specifically, the light source 30 is arranged on the side of the first end surface 10c of the first light guide body 10. For example, the light source 30 is arranged to face the first end surface 10c of the first light guide body 10, and the light emitting surface of the light source 30 faces the first end surface 10c of the first light guide body 10. .. That is, the lighting device 1 is an edge light type lighting device. The optical axis of the light source 30 is in the direction from the first end surface 10c of the first light guide body 10 toward the second end surface 10d. Specifically, the optical axis of the light source 30 is perpendicular to the first end surface 10c of the first light guide body 10 and parallel to the first main surface 10a of the first light guide body 10.

The light source 30 is an LED module including a light emitting diode (LED; Light Emitting Diode). In the present embodiment, the light source 30 emits white light. Therefore, the white light emitted from the light source 30 is incident on the first end surface 10c, which is the light incident surface of the first light guide body 10.

The light source 30 has a light emitting element 31 and a mounting substrate 32 on which the light emitting element 31 is mounted. One or more light emitting elements 31 are mounted on the mounting board 32. In this embodiment, a plurality of light emitting elements 31 are mounted on the mounting board 32. The mounting board 32 is a long board, for example, a wiring board in which metal wiring is formed in a predetermined pattern. As the base substrate of the mounting substrate 32, a resin substrate, a ceramic substrate, an insulating coated metal substrate, or the like can be used.

The light emitting element 31 is an LED light source composed of LEDs. Specifically, the light emitting element 31 is a white LED light source that emits white light. The light emitting element 31 is, for example, an individually packaged surface mount (SMD) type LED element, and is a white resin or ceramic container (package) having a recess and a concave portion of the container. It includes one or more LED chips primarily mounted on the bottom and a sealing member that is filled in the recesses of the container to seal the LED chips. The sealing member is made of a translucent resin material such as a silicone resin. The sealing member may be a phosphor-containing resin containing a wavelength conversion material such as a phosphor.

The LED chip is an example of a semiconductor light emitting device that emits light by a predetermined DC power, and is a bare chip that emits monochromatic visible light. The LED chip is, for example, a blue LED chip that emits blue light when energized. In this case, in order to obtain white light, the sealing member contains a yellow phosphor such as YAG (yttrium aluminum garnet) that fluoresces with blue light from the blue LED chip as excitation light.

As described above, the light emitting element 31 in the present embodiment is a white LED element composed of a blue LED chip and a yellow phosphor. Specifically, the yellow phosphor absorbs a part of the blue light emitted by the blue LED chip and is excited to emit the yellow light, and this yellow light and the blue light not absorbed by the yellow phosphor are mixed. Becomes white light. The sealing member is not limited to the yellow fluorescent substance, and may contain a red fluorescent substance and a green fluorescent substance.

The plurality of light emitting elements 31 are arranged in a line on the mounting board 32 along the longitudinal direction of the mounting board 32. The plurality of light emitting elements 31 arranged in a line shape function as a line light source that emits light in a line shape. In the present embodiment, the plurality of light emitting elements 31 are mounted in a row at substantially equal intervals along the longitudinal direction of the mounting substrate 32. Each light emitting element 31 is arranged on the mounting substrate 32 so that the main light emitting surface faces the first end surface 10c (light incident surface) of the first light guide body 10.

The light source 30 may be a COB (Chip On Board) type LED module instead of an SMD type LED module. When the light source 30 is a COB type LED module, the light emitting element which is an LED chip is directly mounted on the mounting substrate 32. In this case, for example, a blue LED chip is used as a light emitting element, a plurality of the blue LED chips are mounted in a row on the mounting substrate 32, and the blue LED chip is formed by a sealing member made of a silicone resin containing a yellow phosphor. It may be sealed individually or collectively.

Further, a light distribution variable mechanism such as a lens that changes the light distribution of the light emitted from the light source 30 and the wavelength of the light emitted from the light source 30 are controlled as needed separately from the light source 30 or as a part of the light source 30. Or an optical member such as a diffuser that scatters and transmits the light emitted from the light source 30 may be provided.

The light source 30 is driven by electric power supplied from a power supply unit (not shown). The power supply unit has, for example, a power supply (power supply circuit) composed of a circuit board on which a plurality of circuit components are mounted, and a housing for accommodating the power supply. The power source converts the electric power received by the power supply unit into a predetermined electric power and supplies the electric power to the light source 30. As a result, the light source 30 is driven to emit light. The power supply unit may be included in the lighting device 1 or may be provided separately from the lighting device 1. That is, the lighting device 1 may be of a built-in power supply type or may be one that supplies electric power from an external power source.

Further, the light source 30 may be arranged in a housing (not shown). The housing is, for example, a box-shaped storage member having a bottomed cylinder having an opening, and is made of, for example, a metal material or a resin material. The light source 30 is arranged at the bottom of the housing. In this case, the mounting board 32 of the light source 30 is mounted on the bottom surface of the housing. Further, the opening of the housing may be closed by the first end surface 10c of the first light guide body 10, but the present invention is not limited to this. The light source 30 and the housing may be integrally configured as a light source unit.

As shown in FIGS. 1A and 1B, the first light guide body 10 and the second light guide body 20 are held by the holding member 40. The holding member 40 is a holder that holds the first light guide body 10 and the second light guide body 20. Specifically, in the holding member 40, the first light guide body 10 and the second light guide body 20 are in a state where the first light guide body 10 and the second light guide body 20 are overlapped with each other via the air layer 2. Holds both ends of the.

In the present embodiment, the holding member 40 is composed of a pair of the first holding tool 41 and the second holding tool 42. Each of the first holder 41 and the second holder 42 is a frame having a U-shaped cross section.

As shown in FIG. 1B, in the first holder 41 and the second holder 42, the first light guide body 10 and the second guide body 20 are in a state where the first light guide body 10 and the second light guide body 20 are overlapped with each other. The outer peripheral end of the optical body 20 is sandwiched. Specifically, the first holder 41 covers one side surface of the first light guide body 10 in the Y-axis direction and one side surface of the second light guide body 20 in the Y-axis direction. The outer peripheral end portion of the second main surface 10b of the light guide body 10 and the outer peripheral end portion of the fourth main surface 20b of the second light guide body 20 are sandwiched. Further, the second holder 42 covers the other side surface of the first light guide body 10 in the Y-axis direction and the other side surface of the second light guide body 20 in the Y-axis direction so as to cover the first light guide body. The outer peripheral end portion of the second main surface 10b of 10 and the outer peripheral end portion of the fourth main surface 20b of the second light guide body 20 are sandwiched.

Next, the optical characteristics of the lighting device 1 according to the present embodiment will be described in comparison with the optical characteristics of the lighting device 1X of the comparative example.

First, the optical characteristics of the lighting device 1X of the comparative example will be described with reference to FIGS. 4A to 4C. FIG. 4A is a diagram showing a configuration and a light distribution image of the lighting device 1X of the comparative example. FIG. 4B is a diagram for explaining the optical action of the lighting device 1X. FIG. 4C is a diagram showing the light distribution of the lighting device 1X.

As shown in FIG. 4A, the lighting device 1 of the comparative example has a configuration in which the second light guide body 20 is not provided in the lighting device 1 of the above embodiment. That is, the lighting device 1 of the comparative example includes only the first light guide body 10 among the first light guide body 10 and the second light guide body 20 in the lighting device 1 in the above embodiment.

As shown in FIG. 4A, in the lighting device 1X of the comparative example, the light emitted from the light source 30 is incident on the first light guide body 10 from the first end surface 10c of the first light guide body 10. The incident light L1 of the light source 30 incident on the first light guide body 10 is the first toward the direction from the first end surface 10c to the second end surface 10d while repeating total reflection on the first main surface 10a and the second main surface 10b. 1 Light guides the inside of the light guide body 10.

Then, as shown in FIG. 4B, a part of the incident light L1 that guides the inside of the first light guide body 10 that has reached the concave prism 11 is totally reflected at the interface between the concave prism 11 and the air layer. It becomes the reflected light L1a. The reflected light L1a guides the light toward the second main surface 10b and emits light from the second main surface 10b to the outside of the first light guide body 10.

In the lighting device 1X of the comparative example configured as described above, the reflected light L1a reflected by the concave prism 11 can be controlled by adjusting the shape and arrangement of the concave prism 11, so that it becomes a light extraction surface. The light distribution angle of the light emitted to the outside from the second main surface 10b can be controlled. That is, the reflected light L1a reflected by the concave prism 11 can be controlled as the control light. For example, by adjusting the base angle (prism angle) of the concave prism 11, the direction of the reflected light L1a reflected by the concave prism 11 can be adjusted. Thereby, as shown by the broken line ellipse in FIG. 4A, the direction of the control light emitted from the second main surface 10b to the outside can be adjusted.

However, in the lighting device 1X of Comparative Example 1, as shown in FIG. 4B, the other part of the incident light L1 that has reached the concave prism 11 is not totally reflected at the interface between the concave prism 11 and the air layer. It becomes the transmitted light L1b transmitted through the concave prism 11. The transmitted light L1b becomes leaky light and leaks to the outside from the first main surface 10a of the first light guide body 10.

Specifically, as shown by the light distribution distributed by the broken line in FIG. 4C, almost no leaked light is observed in the YZ cross section of the first light guide body 10, but the light distribution distributed by the solid line in FIG. 4C. As described above, leakage light is generated in the XZ cross section. That is, leakage light is likely to occur in the traveling direction of the light emitted from the light source 30 (X-axis direction in FIG. 4A). Moreover, this leaked light is difficult to control.

As described above, in the lighting device 1X of the comparative example using only the first light guide body 10, a lot of light that is difficult to control is included in the light emitted from the first light guide body 10.

Next, the optical characteristics of the lighting device 1 according to the present embodiment will be described with reference to FIGS. 5A to 5C. FIG. 5A is a diagram showing a configuration and a light distribution image of the lighting device 1 according to the embodiment. FIG. 5B is a diagram for explaining the optical action of the lighting device 1. FIG. 5C is a diagram showing the light distribution of the lighting device 1.

As shown in FIG. 5A, in the lighting device 1 according to the present embodiment, the light emitted from the light source 30 is incident on the first light guide body 10 from the first end surface 10c of the first light guide body 10. The incident light L1 of the light source 30 incident on the first light guide body 10 is from the first end surface 10c while repeating total reflection on the first main surface 10a and the second main surface 10b, similarly to the lighting device 1 of the comparative example. The inside of the first light guide body 10 is guided toward the second end surface 10d.

Then, as shown in FIG. 5B, a part of the incident light L1 that guides the inside of the first light guide body 10 and reaches the concave prism 11 is the concave prism 11 as in the lighting device 1 of the comparative example. The reflected light L1a is totally reflected at the interface between the light and the air layer 2. The reflected light L1a guides the light toward the second main surface 10b and emits light from the second main surface 10b to the outside of the first light guide body 10.

Further, the other part of the incident light L1 that has reached the concave prism 11 passes through the concave prism 11 without being totally reflected at the interface between the concave prism 11 and the air layer, as in the lighting device 1 of the comparative example. It becomes transmitted light L1b. At this time, in the lighting device 1 of the present embodiment, unlike the lighting device 1 of the comparative example, the second light guide body 20 having the convex prism 21 fitted to the concave prism 11 is arranged, so that the first light guide body 20 is arranged. The transmitted light L1b transmitted through the concave prism 11 of the light guide body 10 is incident on the inside of the second light guide body 20 from the convex prism 21.

In this case, the convex prism 21 has a shape that fits with the concave prism 11, and the surface of the convex prism 21 and the surface of the concave prism 11 are parallel to each other. Therefore, the transmitted light L1b transmitted through the concave prism 11 is convex. It passes straight through the convex prism 21 with almost no refraction on the surface of the prism 21 and is incident on the inside of the second light guide body 20.

The transmitted light L1b incident on the second light guide body 20 is transferred from the third end surface 20c to the fourth end surface 20d while repeating total reflection on the third main surface 20a and the fourth main surface 20b of the second light guide body 20. The inside of the second light guide body 20 is guided toward the direction. Then, a part of the transmitted light L1b that has reached the fourth main surface 20b of the second light guide 20 is emitted to the outside from the fourth main surface 20b, but is emitted to the fourth main surface 20b of the second light guide 20. The other part of the transmitted light L1b that has reached is totally reflected by the fourth main surface 20b of the second light guide body 20 and travels toward the third main surface 20a on which the convex prism 21 is formed. ..

The transmitted light L1b reflected by the fourth main surface 20b and reaching the convex prism 21 passes through the convex prism 21 and re-enters the first light guide 10 from the concave prism 11. At this time, as described above, the convex prism 21 has a shape that fits with the concave prism 11, and the surface of the convex prism 21 and the surface of the concave prism 11 are parallel to each other. The transmitted light L1b incident on the concave prism 11 travels straight on the surface of the concave prism 11 with almost no refraction, and is incident on the inside of the first light guide body 10.

The transmitted light L1b re-entering the first light guide body 10 from the second light guide body 20 via the convex prism 21 and the concave prism 11 guides the inside of the first light guide body 10. In this way, the transmitted light L1b transmitted through the concave prism 11 of the first light guide body 10 and incident on the second light guide body 20 becomes light that guides the first light guide body 10 again. According to the simulation results of the present inventors, it was found that the transmitted light L1b incident on the first light guide body 10 to the second light guide body 20 returns to the first light guide body 10 at a high ratio. rice field.

Then, the transmitted light L1b re-entered from the second light guide body 20 to the first light guide body 10 guides the inside of the first light guide body 10 again from the first end surface 10c toward the second end surface 10d. It is emitted to the outside from the second main surface 10b (light extraction surface) of the first light guide body 10. Specifically, the light incident on the first light guide body 10 from the light source 30 can be taken out from the second main surface 10b of the first light guide body 10 as planar illumination light. For example, a part of the transmitted light L1b incident on the first light guide body 10 from the convex prism 21 via the concave prism 11 travels straight through the inside of the first light guide body 10 and is totally reflected by the second main surface 10b. The first light guide from the second main surface 10b is emitted from the second main surface 10b to the outside of the first light guide body 10 without doing so, or while total reflection is repeated between the second main surface 10b and the first main surface 10a. It emits light to the outside of the body 10.

As described above, according to the lighting device 1 according to the present embodiment, the transmitted light L1b, which becomes leakage light in the lighting device 1X of the comparative example, is incident on the second light guide body 20 from the convex prism 21. It can be returned to the first light guide body 10 again and emitted from the second main surface 10b of the first light guide body 10, which is the front surface of the lighting device 1. That is, in the lighting device 1 according to the present embodiment, the light that becomes the leakage light can be converted into the control light and used as the illumination light.

Specifically, as in the light distribution in the XZ cross section shown by the solid line in FIG. 4C above, a large amount of leaked light was generated in the lighting device 1X of the comparative example, but it is shown by the solid line in FIG. 5C. It can be seen that almost no light leakage is generated in the lighting device 1 in the present embodiment, as in the light distribution in the XZ cross section.

As described above, according to the lighting device 1 according to the present embodiment, the amount of light (control light) that can be controlled is increased by using the second light guide body 20 in addition to the first light guide body 10. be able to.

Moreover, as shown in FIG. 5C, the back light (back surface light) emitted to the outside from the fourth main surface 20b (back surface) of the second light guide body 20 is not in an oblique direction with respect to the fourth main surface 20b. It was also found that the light was emitted in the direction perpendicular to the fourth main surface 20b. That is, although the fourth main surface 20b of the second light guide 20 is the back surface of the lighting device 1, the rear light emitted from the fourth main surface 20b of the second light guide 20 is emitted from the first light guide 10. Similar to the front light emitted from the second main surface 10b, it can be taken out in the direction perpendicular to the fourth main surface 20b (opposite direction). As a result, in the lighting device 1 according to the present embodiment, although the first light guide body 10 and the second light guide body 20 are overlapped with each other, the transparency can be maintained. Further, in the lighting device 1 according to the present embodiment, the back light can be used as the control light. In this case, not only the second main surface 10b of the first light guide body 10 but also the second main surface 40b of the second light guide body 20 becomes a light emitting surface that emits light in a pseudo manner. That is, the fourth main surface 20b of the second light guide body 20 also serves as a light extraction surface.

Further, in the lighting device 1 of the present embodiment, the ratio of the light flux of the light emitted from the front side (front light) to the light flux of the light emitted from the back side (rear light) with respect to the lighting device 1X of the comparative example. Can also be changed. Specifically, in the lighting device 1X of the comparative example, the luminous flux of the light (front light) emitted to the outside from the second main surface 10b of the first light guide body 10 and the first main surface 10a of the first light guide body 10 The ratio of the light emitted from the light (rear light) to the light flux was 1.2: 1. On the other hand, in the lighting device 1 according to the present embodiment, the luminous flux of the light (front light) emitted to the outside from the second main surface 10b of the first light guide body 10 and the fourth main surface 20b of the second light guide body 20 The ratio of the light emitted from the light (rear light) to the light flux was 2.5: 1. As described above, in the lighting device 1 of the present embodiment, the luminous flux of the front light with respect to the back light can be increased, and the ratio of the light that can be taken out from the front can be increased. As a result, it is possible to realize light distribution characteristics that have been difficult to realize until now.

Here, the influence of the skirt angle θ (prism angle) of the concave prism 11 of the first light guide body 10 and the convex prism 21 of the second light guide body 20 on the front light and the back light was examined by simulation. The results will be described with reference to FIG. FIG. 6 is a diagram showing the relationship between the base angle θ of the concave prism 11 and the convex prism 21 and the luminous flux of the front light, the luminous flux of the back light, the instrument efficiency, and the light distribution in the lighting device 1 according to the embodiment. be. The fixture efficiency is the light extraction efficiency as a lighting device.

In this simulation, the shapes of the concave prism 11 and the convex prism 21 formed in the central 60 mm square rectangular region of the 100 mm square rectangular light guide plate (length 100 mm × width 100 mm) are formed into an axially symmetric conical shape (φ250 μm) and are 60 mm. The number of concave prisms 11 and convex prisms 21 is set so that the coverage, which is the area occupied by the prisms in the rectangular region of the corner, is 30%, and the thickness of the first light guide body 10 and the second light guide body 20 is 2 mm. The thickness of the air layer 2 between the concave prism 11 and the convex prism 21 was 0.01 mm. Further, on each end surface of the first light guide body 10 and the second light guide body 20 (excluding the light incident surface on which the light source 30 is arranged), a reflective member that reflects the light emitted from the end face again into the light guide body is provided. It is arranged.

Then, the base angles θ of the concave prism 11 and the convex prism 21 were changed to 20 °, 30 °, 32.5 °, 35 °, 40 °, 45 °, 50 °, 55 °, 60 °, and 65 °. Occasionally, the luminous flux of the front light, the luminous flux of the back light, the efficiency of the fixture, and the light distribution were obtained. Further, the control light ratio was calculated as the control light ratio = front light / back light. The results are shown in FIG.

As shown in FIG. 6, it can be seen that the instrument efficiency (light extraction efficiency) decreases as the base angle θ decreases. On the contrary, as the skirt angle θ increases, the instrument efficiency increases.

It can be seen that when the base angle θ of the concave prism 11 and the convex prism 21 is 20 ° or more and 40 ° or less, the luminous flux of the back light is smaller than the luminous flux of the front light, and the control light ratio is high. In this case, it was found that the control light ratio became the maximum (maximum) near 32.5 °.

Further, as shown in the light distribution distribution in FIG. 6, when the base angle θ exceeds 40 °, the light distribution angle of the back light becomes higher, and the emission direction of the back light becomes the front side of the back surface. .. By setting the skirt angle θ of the concave prism 11 and the convex prism 21 to at least 45 ° or more and 60 ° or less in this way, the light distribution angles of the front light and the back light can be increased to be in the front direction. It was also found that the front light and the back light are distributed in two directions by setting the skirt angle θ to about 50 ° to 60 °.

Next, the influence of the thickness of the second light guide body 20 (convex light guide plate) on the front light and the back light was examined by simulation, and the examination results will be described with reference to FIG. 7. FIG. 7 is a diagram showing the relationship between the thickness of the second light guide body 20 and the luminous flux of the front light, the luminous flux of the back light, the efficiency of the fixture, and the light distribution in the lighting device 1 according to the embodiment.

In this simulation, the shapes of the concave prism 11 and the convex prism 21 are axially symmetric conical shapes (φ250 μm), the first light guide body 10 is an acrylic plate having a thickness of 2 mm, and the air between the concave prism 11 and the convex prism 21 is formed. The thickness of the layer 2 was 0.01 mm, and the base angle θ of the concave prism 11 and the convex prism 21 was 50 °.

Then, when the thickness of the second light guide body 20 made of an acrylic plate is changed to 2 mm, 1.5 mm, 1.0 mm, and 0.7 mm, the light flux of the front light, the light flux of the back light, the instrument efficiency, and the arrangement are arranged. The light distribution was obtained. The results are shown in FIG.

As shown in FIG. 7, it can be seen that the instrument efficiency (light extraction efficiency) increases as the thickness of the second light guide 20 decreases. It can also be seen that the thickness of the second light guide 20 has almost no effect on the light distribution. Therefore, the thickness of the second light guide body 20 should be smaller than the thickness of the first light guide body 10. As a result, the light extraction efficiency of the lighting device 1 can be increased.

Next, the effect of the thickness of the air layer 2 between the concave prism 11 and the convex prism 21 (the gap between the first light guide 10 and the second light guide 20) on the front light and the back light is simulated. The results of the study will be described with reference to FIG. FIG. 8 shows the thickness of the air layer 2 between the concave prism 11 and the convex prism 21, the luminous flux of the front light, the luminous flux of the back light, the efficiency of the fixture, and the light distribution in the lighting device 1 according to the embodiment. It is a figure which shows the relationship.

In this simulation, the shapes of the concave prism 11 and the convex prism 21 are axially symmetric conical shapes (φ250 μm), the first light guide 10 and the second light guide 20 are acrylic plates having a thickness of 2 mm, and the concave prism 11 and the convex are convex. The skirt angle θ of the prism 21 was set to 50 °.

Then, when the thickness of the air layer 2 is changed to 0.01 mm, 0.05 mm, and 0.10 mm (that is, the gap between the first light guide body 10 and the second light guide body 20 is changed). Then, the luminous flux of the front light, the luminous flux of the back light, the efficiency of the fixture, and the light distribution were obtained. The results are shown in FIG.

As shown in FIG. 8, the concave prism 11 and the convex prism 21 may be brought close to each other so that the thickness of the air layer 2 is about 0.05 mm or less. That is, when the thickness of the air layer 2 is 0.05 mm, the thickness of the air layer 2 is less than half the depth of the concave prism 11 or the thickness of the air layer 2 is less than half the height of the convex prism 21. .. Therefore, the thickness of the air layer 2 is preferably not more than half the depth of the concave prism 11 or less than half the height of the convex prism 21.

As described above, the lighting device 1 according to the present embodiment has a first light source 10 having a concave prism surface on which a plurality of concave prisms 11 are formed, and a convex prism on which a plurality of convex prisms 21 are formed. A second light guide body 20 having a surface and a light source 30 that emits light incident on at least one end surface of the first light guide body 10 and the second light guide body 20 are provided. The 10 and the second light guide body 20 are arranged so that a plurality of concave prisms 11 and a plurality of convex prisms 21 are fitted to each other via the air layer 2.

As a result, the light that becomes the leakage light can be converted into the control light, and the control light that can be controlled by the first light guide body 10 and the second light guide body 20 can be increased. Therefore, it is possible to realize a lighting device having high light extraction efficiency.

In this case, the plurality of concave prisms 11 and the plurality of convex prisms 21 may have an axisymmetric conical shape or a hemispherical shape.

With this configuration, uncontrollable light (uncontrolled light) is less likely to be generated, so that the amount of controlled light can be further increased.

Further, in the lighting device 1 according to the present embodiment, the light source 30 is arranged so that the light emitted from the light source 30 is incident on the first end surface 10c of the first light guide body 10.

With this configuration, it is possible to increase the light extraction efficiency as compared with the case where the light emitted from the light source 30 is incident on the third end surface 20c of the second light guide body 20.

(Modification example)
The lighting device according to the present invention has been described above based on the embodiment, but the present invention is not limited to the above embodiment.

For example, in the above embodiment, only two light guide plates, the first light guide body 10 and the second light guide body 20, are used, but the present invention is not limited to this. Specifically, in addition to the first light guide body 10 and the second light guide body 20, another third light guide body may be used.

In this case, as in the lighting device 1A according to the first modification shown in FIG. 9, in addition to the first light guide body 10 and the second light guide body 20A, the light guide body 20A is opposed to the second light guide body 20A. The third light guide body 50 may be arranged.

The third light guide body 50 includes a fifth main surface 50a, a sixth main surface 50b facing back to the fifth main surface 50a, a fifth end surface 50c, and a sixth end surface 50d facing back to the fifth end surface 50c. Have. The fifth main surface 50a of the third light guide body 50 is a surface on the side of the second light guide body 20A, and is a concave prism surface on which a plurality of concave prisms 51 each having a concave shape are formed. Specifically, the third light guide body 50 has the same structure as the first light guide body 10. Therefore, the same light guide plate can be used for the third light guide body 50 and the first light guide body 10.

In this modification, in the second light guide body 20A, assuming that the plurality of convex prisms 21 formed on the third main surface 20a are the first convex prisms, the fourth main surface which is the surface on the third light guide body 50 side. A convex prism 22 is formed on the 20b as a plurality of second convex prisms each having a convex shape. That is, the second light guide body 20A is a double-sided convex prism light guide plate having convex prisms formed on both sides.

Then, in the lighting device 1A in the present modification, similarly to the above embodiment, the plurality of concave prisms 11 of the first light guide body 10 and the plurality of convex prisms 21 (first convex prisms) of the second light guide body 20A. The first light guide body 10 and the second light guide body 20A are arranged so that the light and the light can be fitted to each other via the air layer 2. In the lighting device 1A in the present modification, the plurality of convex prisms 22 (second convex prisms) of the second light guide 20A and the plurality of concave prisms 51 of the third light guide 50 are further interposed via the air layer 2. The second light guide body 20A and the third light guide body 50 are arranged so as to be fitted. Specifically, the first light guide body 10, the second light guide body 20A, and the third light guide body 50 are laminated with each other via the air layer 2. That is, the second light guide 20A having convex prisms 21 and 22 formed on both sides, the first light guide 10 having a concave prism 11 formed on one side, and the third guide having a concave prism 51 formed on one side. It is configured to be sandwiched between the light body 50 and the light body 50.

Further, in the lighting device 1A in this modification, two light sources 30 are used. Specifically, one of the two light sources 30 is arranged so that the light emitted from the light source 30 is incident on the first end surface 10c of the first light guide body 10, as in the above embodiment. On the other hand, the other of the two light sources 30 is arranged so that the light emitted from the light source 30 is incident on the fifth end surface 50c of the third light guide body 50. More specifically, one of the two light sources 30 is arranged to face the first end surface 10c of the first light guide body 10, and the other of the two light sources 30 is the third light guide body 50. 5 It is arranged so as to face the end surface 50c. That is, the two light sources 30 are arranged on the side of the light guide plate (first light guide body 10 and third light guide body 50) on which the concave prism is formed.

As described above, the lighting device 1A in the present modification further includes the third light guide body 50 facing the second light guide body 20A with respect to the lighting device 1 according to the above embodiment. In this case, the convex prism 22 of the second light guide 20A and the concave prism 51 of the third light guide 50 are the same as the concave prism 11 of the first light guide 10 and the convex prism 21 of the second light guide 20A. In addition, it has a structure in which it is fitted via the air layer 2. As a result, the fourth main surface 20b of the second light guide body 20A is based on the same principle as the optical action of the concave prism 11 of the first light guide body 10 and the convex prism 21 of the second light guide body 20 in the above embodiment. The light leaking from the light guide body 50 can be guided to the third light guide body 50 and re-entered into the second light guide body 20A. Therefore, the lighting device 1A in this modification can improve the light extraction efficiency as compared with the lighting device 1 according to the above embodiment.

Next, the second modification will be described. When the third light guide body is used, the third light guide body 50 is arranged to face the second light guide body 20 as in the lighting device 1A according to the modification 1 shown in FIG. Instead, the third light guide body 60 may be arranged to face the first light guide body 10B as in the lighting device 1B according to the second modification shown in FIG.

The third light guide body 60 in this modification has a fifth main surface 60a, a sixth main surface 60b facing back to the fifth main surface 60a, a fifth end surface 60c, and a third facing back to the fifth end surface 60c. It has 6 end faces 60d. The fifth main surface 60a of the third light guide body 60 is a surface on the side of the first light guide body 10B, and is a convex prism surface on which a plurality of convex prisms 61 each having a convex shape are formed. Specifically, the third light guide body 60 has the same structure as the second light guide body 20. Therefore, the same light guide plate can be used for the third light guide 60 and the second light guide 20.

In this modification, in the first light guide body 10B, assuming that the plurality of concave prisms 11 formed on the first main surface 10a are the first concave-convex prisms, the second main surface which is the surface on the third light guide body 60 side. A concave prism 12 is formed on the 10b as a plurality of second concave prisms each having a concave shape. That is, the first light guide body 10B is a double-sided concave prism light guide plate having concave prisms formed on both sides.

Then, in the lighting device 1B in the present modification, as in the above embodiment, the plurality of concave prisms 11 (first concave prisms) of the first light guide body 10B and the plurality of convex prisms 21 of the second light guide body 20 are obtained. The first light guide body 10B and the second light guide body 20 are arranged so that the light and the light can be fitted to each other via the air layer 2. In the lighting device 1B in the present modification, the plurality of concave prisms 11 (second concave prisms) of the first light guide body 10B and the plurality of convex prisms 61 of the third light guide body 60 are further interposed via the air layer 2. The first light guide body 10B and the third light guide body 60 are arranged so as to be fitted. Specifically, the first light guide body 10B, the second light guide body 20, and the third light guide body 50 are laminated with each other via the air layer 2. That is, the first light guide body 10B having concave prisms 11 and 12 formed on both sides, the second light guide body 20 having a convex prism 21 formed on one side, and the third guide having a convex prism 61 formed on one side. It is configured to be sandwiched between the light body 60 and the light body 60. In this modification, the light source 30 is arranged on the side of only the light guide plate (first light guide body 10B) on which the concave prism is formed.

As described above, the lighting device 1B in the present modification further includes a third light guide body 60 facing the first light guide body 10B with respect to the lighting device 1 according to the above embodiment. In this case, the concave prism 12 of the first light guide body 10B and the convex prism 61 of the third light guide body 60 are the same as the concave prism 11 of the first light guide body 10B and the convex prism 21 of the second light guide body 20. In addition, it has a structure in which it is fitted via the air layer 2. This makes it possible to increase the amount of light that can be extracted from the first main surface 10a of the first light guide body 10B. Therefore, the lighting device 1B in this modification can improve the light extraction efficiency as compared with the lighting device 1 according to the above embodiment.

Next, a modification 3 will be described. In the lighting device 1 in the above embodiment, the light emitted from the light source 30 is incident on the first light guide body 10, but the present invention is not limited to this. For example, as in the lighting device 1C according to the modification 3 shown in FIG. 11, the light emitted from the light source 30 may be incident on the second light guide body 20. That is, as shown in FIG. 11, the light source 30 may be arranged so that the light emitted from the light source 30 is incident on the third end surface 20c of the second light guide body 20. Specifically, in this modification, the light source 30 is arranged on the side of the third end surface 20c of the second light guide body 20. For example, the light source 30 is arranged to face the third end surface 20c of the second light guide body 20, and the light emitting surface of the light source 30 faces the third end surface 20c of the second light guide body 20. ..

Even with the configuration of the lighting device 1C according to the present modification, the same effect as that of the lighting device 1 according to the above embodiment can be obtained. However, the lighting device 1C according to the present modification is light as compared with the lighting device 1 according to the above embodiment, which is configured to incident the light emitted from the light source 30 on the first end surface 10c of the first light guide body 10. The extraction efficiency will be low. Therefore, in the lighting device 1C according to the present modification, the thickness of the first light guide body 10 may be smaller than the thickness of the second light guide body 20. This makes it possible to improve the light extraction efficiency.

Here, the lighting device 1 in the above embodiment, the lighting device 1A of the modification 1 shown in FIG. 9, the lighting device 1B of the modification 2 shown in FIG. 10, and the modification 3 shown in FIG. 11 A simulation was performed for the lighting device 1C in order to compare the luminous flux of the front light, the luminous flux of the back light, the efficiency of the fixture, and the light distribution. The results will be described with reference to FIG. FIG. 12 is a diagram showing a luminous flux of front light, a luminous flux of back light, an instrument efficiency, and a light distribution distribution in each of the lighting devices of the embodiment, the modified example 1, the modified example 2, and the modified example 3.

In this simulation, the first light guide body 10 and the second light guide body 20 are made of an acrylic plate having a thickness of 2 mm, the shapes of the concave prism 11 and the convex prism 21 are made into an axially symmetric conical shape, and the concave prism 11 and the convex prism 21 are formed. The base angle θ was set to 55 °, and the thickness of the air layer 2 between the concave prism 11 and the convex prism 21 was set to 0.01 mm.

As a result, as shown in FIG. 12, by using the third light guide bodies 50 and 60 in addition to the first light guide body 10 and the second light guide body 20, the first light guide body 10 and the second light guide are used. It was found that the light distribution was symmetrical on the front surface and the back surface and the light extraction efficiency was improved as compared with the case where only the body 20 was used. It was also found that the light emitted from the light source 30 has higher light extraction efficiency when it enters the light guide body on which the concave prism is formed.

Next, the lighting device 1D according to the modified example 4 will be described with reference to FIG. FIG. 13 is a cross-sectional view showing the configuration of the lighting device 1D according to the modified example 4. Note that FIG. 13 is a cross-sectional view corresponding to FIG. 1C.

As shown in FIG. 13, the lighting device 1D according to the present modification is configured to further include a reflection member 70 with respect to the lighting device 1 according to the above embodiment. Other than that, it is the same as the lighting device 1 according to the above embodiment.

The reflective member 70 has a function of reflecting light. The reflective member 70 may have a mirror surface property or a white surface. In this modification, the reflective member 70 has a mirror surface property. As an example, the reflective member 70 is a reflective sheet on which a metal film having a mirror surface property is formed. The reflective member 70 is not limited to the metal material, and may be made of a resin material such as a white resin, or may be made of a metal material and a resin material.

The reflective member 70 is arranged so as to face the second main surface 10b of the first light guide body 10 or the fourth main surface 20b of the second light guide body 20. With this configuration, light can be extracted from only one of the second main surface 10b of the first light guide body 10 and the fourth main surface 20b of the second light guide body 20. In this modification, since the second main surface 10b of the first light guide body 10 is the light extraction surface (front surface), the reflective member 70 is the fourth main surface 20b (rear surface) of the second light guide body 20. It is arranged facing the. Specifically, the reflective member 70 is arranged so that the reflective surface of the reflective member 70 is in contact with the fourth main surface 20b of the second light guide body 20. As a result, the light leaking from the fourth main surface 20b of the second light guide 20 can be reflected by the reflecting member 70 and returned to the second light guide 20, so that the second main of the first light guide 10 can be returned. Light can be emitted to the outside only from the surface 10b.

Next, the lighting device 1E according to the modified example 5 will be described with reference to FIGS. 14A to 14C. FIG. 14A is a perspective view of the lighting device 1E according to the modified example 5. FIG. 14B is a cross-sectional view of the illuminating device 1E when cut along the XIVB-XIVB line of FIG. 14A. 14C is a cross-sectional view of the illuminating device 1E when cut along the XIVC-XIVC line of FIG. 14A.

As shown in FIGS. 14A to 14C, the lighting device 1E according to the present modification further refers to the lighting device 1 according to the above embodiment, further with respect to the first reflecting member 81, the second reflecting member 82, and the third reflection. It is configured to include a member 83. Other than that, it is the same as the lighting device 1 according to the above embodiment.

The first reflecting member 81, the second reflecting member 82, and the third reflecting member 83 have a function of reflecting light. The first reflective member 81, the second reflective member 82, and the third reflective member 83 may have mirror surface properties or may have a white surface. In this modification, the first reflective member 81, the second reflective member 82, and the third reflective member 83 have a mirror surface property. As an example, the first reflective member 81, the second reflective member 82, and the third reflective member 83 are reflective sheets on which a metal film having a mirror surface property is formed. The first reflective member 81, the second reflective member 82, and the third reflective member 83 are not limited to the metal material, but may be made of a resin material such as white resin, or may be made of a metal material and a resin material. It may have been done.

The first reflective member 81 is arranged so as to face the second end surface 10d of the first light guide body 10. Specifically, the first reflective member 81 is arranged so that the reflective surface of the first reflective member 81 is in contact with the second end surface 10d.

By arranging the first reflecting member 81 in this way, the light that is about to leak from the second end surface 10d of the first light guide body 10 is reflected by the first reflecting member 81 to be reflected by the first light guide. Since it can be returned to the body 10, it is possible to increase the amount of light emitted to the outside from the second main surface 10b, which is the light extraction surface.

The second reflective member 82 is arranged so as to face the fourth end surface 20d of the second light guide body 20. Specifically, the second reflective member 82 is arranged so that the reflective surface of the second reflective member 82 is in contact with the fourth end surface 20d.

Further, the third reflective member 83 is arranged so as to face the third end surface 20c of the second light guide body 20. Specifically, the third reflective member 83 is arranged so that the reflective surface of the third reflective member 83 is in contact with the third end surface 20c.

By arranging the second reflecting member 82 and the third reflecting member 83 in this way, the light that is about to leak from the third end surface 20c and the fourth end surface 20d of the second light guide body 20 is second. Since the light can be reflected by the reflecting member 82 and the third reflecting member 83 and returned to the second light guide body 20, more light can be re-entered from the second light guide body 20 to the first light guide body 10. .. As a result, it is possible to increase the amount of light emitted to the outside from the second main surface 10b, which is the light extraction surface of the first light guide body 10, so that the light extraction efficiency can be improved.

Next, a modification 5 will be described. In the lighting device 1 according to the above embodiment, the outer peripheral ends of the first light guide body 10 and the second light guide body 20 are sandwiched between the holding members 40. Specifically, the holding member 40 is the first light guide in a direction (X direction in the present embodiment) orthogonal to the light guide direction of the light incident on the first light guide body 10 or the second light guide body 20. A load is applied to both ends of the body 10 and the second light guide body 20.

Therefore, in the lighting device 1 according to the above embodiment, it may be difficult to apply a force to the central portion of the first light guide body 10 and the second light guide body 20. In this case, as shown in FIG. 15, the gap (air layer 2) between the first light guide body 10 and the second light guide body 20 is larger in the central portion than in the outer peripheral end portion. For example, as shown in FIG. 15, the first light guide body 10 and the second light guide body 20 are curved so as to be convex outward.

As described above, when the gap between the first light guide body 10 and the second light guide body 20 becomes large in the central portion, the concave prism 11 in the central portion of the first light guide body 10 and the second light guide body 20. The distance between the light and the convex prism 21 (air layer 2) becomes large. That is, the fitting between the concave prism 11 and the convex prism 21 becomes loose at the central portion. As a result, the optical action of the first light guide body 10 and the second light guide body 20 may become non-uniform in the plane, and the desired light distribution characteristics may not be obtained.

Therefore, as shown in FIG. 16A, in this modification, the first light guide body 10 is warped so as to be convex toward the second light guide body 20 before the load is applied by the holding member 40. At the same time, the second light guide body 20 is warped so as to be convex toward the first light guide body 10. That is, each of the first light guide body 10 and the second light guide body 20 is preliminarily warped so as to be convex in the directions facing each other.

For example, when the first light guide body 10 and the second light guide body 20 are resin-molded, the molding conditions are adjusted so that the first light guide body 10 and the second light guide body 20 are in a warped state in advance. be able to. Alternatively, the flat first light guide body 10 and the second light guide body 20 in a non-warped state are partially stressed and subjected to annealing treatment, whereby the first light guide body 10 and the second light guide body 20 are subjected to an annealing treatment. Can cause warpage.

As described in FIG. 16B, by using the first light guide body 10 and the second light guide body 20 in a state of being warped before the load is applied by the holding member 40, the first light guide is shown. When the outer peripheral ends of the body 10 and the second light guide 20 are sandwiched between the holding members 40 and a load is applied to both ends of the first light guide 10 and the second light guide 20 from the X-axis direction, the first The gap (air layer 2) between the light guide body 10 and the second light guide body 20 can be made uniform over the entire in-plane area. That is, the distance between the concave prism 11 and the convex prism 21 can be made uniform over the entire area of the first main surface 10a of the first light guide body 10 and the third main surface 20a of the second light guide body 20. As a result, the gap between the first light guide body 10 and the second light guide body 20 can be kept constant over time. That is, even if the outer peripheral ends of the first light guide body 10 and the second light guide body 20 are sandwiched between the holding members 40, the fitting state of all the concave prisms 11 and all the convex prisms 21 is the same. At the same time, this state can be maintained for a long period of time. Therefore, since the optical action of the first light guide body 10 and the second light guide body 20 can be maintained constant over the entire in-plane range for a long period of time, a highly reliable lighting device can be realized.

Further, in the above embodiment, only the concave prism 11 is formed on the first main surface 10a (concave prism surface) of the first light guide body 10, and the third main surface 20a (concave prism surface) of the second light guide body 20 is formed. Only the convex prism 22 was formed on the convex prism surface), but the present invention is not limited to this. For example, at least one convex additional convex prism is formed on the first main surface 10a (concave prism surface) on which the plurality of concave prisms 11 of the first light guide 10 are formed, and the second light guide is formed. At least one concave additional concave prism may be formed on the third main surface (convex prism surface) on which the plurality of convex prisms 22 formed in 20 are formed. In this case, the additional convex prism formed on the first light guide body 10 and the additional concave prism formed on the second light guide body 20 are fitted via the air layer in the same manner as the concave prism 11 and the convex prism 21. It fits. The additional convex prism may have the same shape and size as the convex prism 21, or may have a different shape and size from the convex prism 21. Further, the additional concave prism may have the same shape and size as the concave prism 11, or may have a different shape and size from the concave prism 11. The number of sets of the additional convex prism and the additional concave prism may be one or a plurality, but it is better than the number of sets of the concave prism 11 and the convex prism 21. Further, the additional convex prism and the additional concave prism can be applied to the modified example.

Further, in the above embodiment, the first light guide body 10 and the second light guide body 20 are manufactured by injection molding using a mold incorporating a stamper manufactured from the same master. Not exclusively. For example, the first light guide body 10 and the second light guide body 20 may be manufactured by roll transfer using a stamper manufactured from the same master, or may be manufactured by any other method. The first light guide body 10 and the second light guide body 20 may be manufactured without using a stamper manufactured from the same master. However, by manufacturing the first light guide body 10 and the second light guide body 20 using a stamper manufactured from the same master, the gap between the concave prism 11 and the convex prism 21 can be accurately and constantly spaced over the entire area. Therefore, the control light can be controlled more accurately.

Further, other modifications will be described below.

In the above embodiment, the light source 30 is configured to emit white light by the blue LED chip and the yellow phosphor, but the light source 30 is not limited to this. For example, instead of using a yellow phosphor, a phosphor-containing resin containing a red phosphor and a green phosphor may be used, and the combination of this with a blue LED chip may be configured to emit white light. good.

Further, in the above embodiment, the light emitting element 31 of the light source 30 uses a blue LED chip that emits blue light, but the present invention is not limited to this. For example, the light emitting element 31 may use an LED chip that emits a color other than blue. For example, the light emitting element 31 may use an LED chip that emits ultraviolet light. In this case, as the phosphor particles, a combination of three primary colors (red, green, blue) and light emitting phosphors of each color can be used. Further, although a phosphor is used as the wavelength conversion material, a wavelength conversion material other than the phosphor may be used. For example, as the wavelength conversion material, a material containing a substance such as a semiconductor, a metal complex, an organic dye, or a pigment that absorbs light having a certain wavelength and emits light having a wavelength different from the absorbed light may be used.

Further, in the above embodiment, the light source 30 is an LED module using an LED, but the light source 30 is not limited to this. For example, the light source 30 may be one using a solid-state light emitting element other than an LED such as a semiconductor laser or an organic EL (Electroluminescence), or a fluorescent lamp such as a cold cathode fluorescent lamp (CCFL).

In addition, it is realized by arbitrarily combining the components and functions in the above-described embodiment to the form obtained by applying various modifications to the above-described embodiment and within the range not deviating from the gist of the present invention. Forms are also included in the present invention.

1, 1A, 1B, 1C, 1D, 1E Lighting device 2 Air layer 10, 10B First light source 10a First main surface 10b Second main surface 11, 12, 51 Concave prism 20, 20A Second light source 20a 3rd main surface 20b 4th main surface 21, 22, 61 Convex prism 30 Light source 40 Holding member 50, 60 3rd light guide body 70 Reflecting member 100 Master substrate (master)

Claims (16)

A first light guide body having a prism surface on which a plurality of concave prisms each having a concave shape are formed, and
A second light guide having a prism surface on which a plurality of convex prisms each having a convex shape are formed, and
A light source that emits light incident on at least one end surface of the first light guide body and the second light guide body is provided.
The first light guide body and the second light guide body are arranged so that the plurality of concave prisms and the plurality of convex prisms are fitted with each other via an air layer.
Lighting equipment. The plurality of concave prisms and the plurality of convex prisms have an axisymmetric conical shape or a hemispherical shape.
The lighting device according to claim 1. The plurality of concave prisms and the plurality of convex prisms have an axisymmetric conical shape.
The skirt angle of each of the plurality of concave prisms and the skirt angle of each of the plurality of convex prisms are 45 ° or more and 60 ° or less.
The lighting device according to claim 2. The plurality of concave prisms and the plurality of convex prisms have an axisymmetric conical shape.
The skirt angle of each of the plurality of concave prisms and the skirt angle of each of the plurality of convex prisms are 20 ° or more and 40 ° or less.
The lighting device according to claim 2. The light source is arranged so that the light emitted from the light source is incident on the end face of the first light guide body.
The lighting device according to any one of claims 1 to 4. The first light guide body and the second light guide body are plate-shaped light guide plates.
The thickness of the second light guide body is smaller than the thickness of the first light guide body.
The lighting device according to claim 5. The light source is arranged so that the light emitted from the light source is incident on the end face of the second light guide body.
The lighting device according to any one of claims 1 to 4. The first light guide body and the second light guide body are plate-shaped light guide plates.
The thickness of the first light guide body is smaller than the thickness of the second light guide body.
The lighting device according to claim 7. The first light guide has a first main surface which is a prism surface on which the plurality of concave prisms are formed, and a second main surface which faces back to the first main surface.
The second light guide has a third main surface, which is a prism surface on which the plurality of convex prisms are formed, and a fourth main surface facing back to the third main surface.
The illuminating device further includes a reflective member having a mirror surface property, which is arranged so as to face the second main surface or the fourth main surface.
The lighting device according to any one of claims 1 to 8. The thickness of the air layer is not less than half the depth of each of the plurality of concave prisms or less than half the height of each of the plurality of convex prisms.
The lighting device according to any one of claims 1 to 9. A holding member for holding the first light guide body and the second light guide body is provided.
The holding member loads both ends of the first light guide body and the second light guide body in a direction orthogonal to the light guiding direction of the light incident on the first light guide body or the second light guide body. And
Before applying the load with the holding member, the first light guide body is warped so as to be convex toward the second light guide body, and the second light guide body is the first guide body. It is warped so that it becomes convex toward the light body,
The lighting device according to any one of claims 1 to 10. At least one convex additional convex prism is formed on the prism surface on which the plurality of concave prisms are formed in the first light guide body.
At least one concave additional concave prism is formed on the prism surface on which the plurality of convex prisms are formed in the second light guide body.
The additional convex prism and the additional convex prism are fitted to each other via an air layer.
The lighting device according to any one of claims 1 to 11. Further, a third light guide body having a prism surface, each of which has a plurality of concave prisms having a concave shape, is provided.
The second light guide has a third main surface, which is a prism surface on which the plurality of convex prisms are formed, and a fourth main surface facing back to the third main surface.
Assuming that the plurality of convex prisms formed on the third main surface are the first convex prisms, a plurality of second convex prisms each having a convex shape are formed on the fourth main surface of the second light guide body. Has been
The second light guide body and the third light guide body are arranged so that the plurality of second convex prisms and the plurality of concave prisms of the third light guide body are fitted with each other via an air layer. ing,
The lighting device according to any one of claims 1 to 12. Further, a third light guide body having a prism surface on which a plurality of convex prisms each having a convex shape is formed is provided.
The first light guide has a first main surface which is a prism surface on which the plurality of concave prisms are formed, and a second main surface which faces back to the first main surface.
Assuming that the plurality of concave prisms formed on the first main surface are the first concave prisms, a plurality of second concave prisms each having a concave shape are formed on the second main surface of the first light guide body. Has been
The first light guide body and the third light guide body are arranged so that the plurality of second concave prisms and the plurality of convex prisms of the third light guide body are fitted with each other via an air layer. ing,
The lighting device according to any one of claims 1 to 12. A first light guide body each having a prism surface on which a plurality of concave first prisms are formed, and a second light guide body having a prism surface on which a plurality of convex second prisms are formed. It is a method of manufacturing a lighting device to be equipped.
The first light guide body and the second light guide body are manufactured by a stamper manufactured from the same master.
Manufacturing method of lighting equipment. The first light guide body and the second light guide body are manufactured by injection molding using a mold incorporating the stamper or roll transfer using the stamper.
The method for manufacturing a lighting device according to claim 15.

Images