JP6318383B2 - Linear light source unit structure - Google Patents

Description

The present invention relates to a linear light source unit structure having a simple configuration capable of ensuring sufficient light diffusion on a light emitting surface while reducing the number of point light sources such as LEDs.

For LED lighting devices. Compared with a normal light source, the irradiation light of each LED light source is close to a point light source and has a characteristic of less diffusibility with respect to the optical axis. Usually, when the light emitted from a plurality of LED light sources is transmitted through a light emitting member and used in an automobile lighting device, the light intensity (unevenness) on the light emitting surface is large. On the other hand, many LEDs are used to eliminate the light intensity. When a light source is used, there is a problem that economic efficiency is poor.

In order to solve this problem, for example, in Patent Document 1, in a linear light source unit using a light guide member, in order to improve non-uniformity of the intensity of illumination light, between the light source of the light guide member and the light emitting surface. A hole that combines a paraboloid and a convex surface is provided on the light source side to transmit light incident on the convex surface, and other light is totally reflected by the paraboloid and distributed to the left and right to be emitted from the light emitting surface by secondary reflection. A linear light source unit structure is provided.

However, in the case of the linear light source unit structure of Patent Document 1, it is necessary to separately process a secondary reflecting surface having a parabolic surface, resulting in an increase in cost. Further, in the case of this linear light source unit structure, the light on the light emitting surface is composed of the transmitted light from the convex surface and the reflected light from the parabolic surface, and the problem that the difference in intensity of each light tends to occur, There is a problem that a loss of reflected light occurs due to light leaking from the secondary reflecting surface.

JP 2000-307807 A

The present invention is an invention created in view of such circumstances, and can ensure sufficient light diffusion on the light emitting surface while reducing the number of point light sources such as LEDs, and is also a secondary reflecting surface. It is an object of the present invention to provide an inexpensive linear light source unit structure that requires no processing.

The first aspect of the present invention provided to solve the above-described problems is as follows.
This is a linear light source unit structure that diffuses incident light by providing a hole between the light source side of the light guide member (for example, the light guide 14 in the present embodiment) and the light emitting surface. The shape of the hole (for example, the slit 20 in this embodiment) of the linear light source unit is composed of two surfaces having opposite curvatures on the light source side and the light emitting surface side, and the surface on the light source side is incident from the light source. The curvature of the transmitted light is generally transmitted to the light emitting surface, and the curvature of the light emitting surface is larger than that of the light source. Furthermore, the surface on the light source side of the hole has a substantially arc shape that swells toward the light source side, and the surface on the light emitting surface side of the hole has a substantially arc shape that swells on the light emitting surface side.

According to the present invention, when the light emitted from the light source is incident on the hole, the light is generally diffused and transmitted, and further, the incident angle of the transmitted light to the light emitting surface side is reduced so that there is no loss due to re-condensing. The light is transmitted in a state, enters the light guide member without lowering the light intensity, and is irradiated from the light emitting surface. Therefore, if the main light source unit is adopted, light can be efficiently diffused without reducing the light intensity simply by transmitting the light to the light guide member, and the intensity unevenness of the emitted light on the light emitting surface can be reduced. Can be reduced.

In addition, it is advantageous in that the emitted light on the light emitting surface can be controlled in accordance with the shape of the light guide member such as condensed light, diffused light, and parallel light only by adjusting the curvature of the parabola of the hole in the light guide member. is there. Further, since the intensity of light on the light emitting surface is controlled only by transmitted light, the processing of the secondary reflecting surface as described in Patent Document 1 is unnecessary, and an increase in processing cost can be suppressed. In particular, in the case of a light source with high directivity such as LED lighting, the number of light sources can be reduced, and the cost can be reduced in this respect.

In the second aspect of the present invention, a hole (for example, slits 60 to 62 in the present embodiment) is provided between the light source side of the light guide member (for example, the light guide 54 in the present embodiment) and the light emitting surface. The light source unit structure diffuses the light, and the shape of the hole is a linear slit having an oblique angle with respect to the optical axis from the light source, and at least two are arranged.

According to the second aspect of the present invention, the irradiation light from the light source is reflected in the width direction (lateral direction with respect to the optical axis) by the inclined slit provided in the light guide member, and further reflected by the next slit. The light is emitted from the light emitting surface. As a result, the light path from the light source becomes longer by the amount that passes between the slits as compared with the case where the light simply passes through the light guide member, and is further diffused and emitted from the light emitting surface.

Therefore, also in the linear light source unit structure of the second aspect of the present invention, it is possible to greatly diffuse the emitted light on the light emitting surface only by transmitting the light to the light guide member, and the intensity (unevenness) of the light on the light emitting surface. Can be suppressed. Further, as in the first aspect of the present invention, it is sufficient to provide a slit in the manufacturing process, and it is not necessary to process the secondary reflecting surface. Therefore, an increase in cost during processing can be suppressed. Furthermore, in the case of a light source with high directivity such as LED lighting, the number of light sources can be reduced and the cost can be reduced as in the first aspect of the present invention.

In the present linear light source unit structure, it is possible to secure sufficient light diffusion on the light emitting surface while reducing the number of point light sources such as LEDs, and the processing of the secondary reflecting surface is unnecessary, and the cost for processing is increased. Can be suppressed.

It is a perspective view which shows simply the linear light source unit structure of 1st this invention. It is the schematic plan view which looked at the linear light source unit structure of FIG. 1 from upper direction. It is the experiment example which showed a mode that it actually light-irradiated with the vehicle lighting device using the linear light source unit structure of FIGS. 1-2, (a) is a mode which looked at the vehicle lighting device from the front, (b ) Is a cross-sectional view of (a) as viewed from above. It is the schematic plan view which looked at the linear light source unit structure of 2nd this invention from upper direction. It is a perspective view which shows the conventional linear light source unit structure simply.

<< Conventional linear light source unit structure >>
In the present specification, a conventional linear light source unit structure will be described as a premise for describing the linear light source unit structure of the present invention.

FIG. 5 shows a perspective view of an example of the structure of a conventional linear light source unit structure 100. The linear light source unit structure 100 is an example used as an automobile lighting device, and LEDs as the linear light source 112 are arranged along the support member 113 in the lateral direction (the X direction on the paper surface). In FIG. 5, two LEDs 112 are illustrated for ease of understanding. A plate-shaped light guide 114 is disposed in front of the light irradiation direction (the Y direction on the paper surface) of each LED 112 so that the thick portion is located. When attention is paid to one of the LEDs 112a, the irradiation light 115 is taken into the thickness 114a of the light guide 114, diffuses as shown by the arrow while propagating through the inside, and is irradiated to the outside from the light emitting surface 114b. FIG. 5 shows that the portion that emits light on the light emitting surface 114b at this time is the region a.

Next, paying attention to the other LED 112b, the irradiation light 116 is also taken into the thickness 114a of the light guide 114, diffuses while propagating through the inside, and is emitted to the outside from the light emitting surface 114a. In FIG. 5, a portion that emits light on the light emitting surface 114b is indicated by a region c.

In the case of irradiation light 115 and 116 from a point light source with high directivity such as LED 112, it is very dark in a region where light is not diffused (see region b of light emitting surface 114b in FIG. 5), and light intensity as a light emitter Unevenness (non-uniformity (including spotlight)) occurs. In order to eliminate the presence of this region b, in general, (1) the distance between the LEDs 112 is reduced, (2) the distance L of the light guide 114 in the light traveling direction is increased, and (3) the surface of the light emitting surface 114b. It is possible to perform a diffusion process (see reference numerals 23 and 63 in FIGS. 1, 2, and 4 described later).

In the case of (1), it is advantageous in that the light emitting area a and the light emitting area c of the light emitting surface 114b overlap and the area b disappears, but it is necessary to increase the number of LEDs 112, resulting in an increase in cost. There is a problem, and there is a possibility that unevenness in the intensity of light in a portion where the light emission region a and the light emission region c overlap with each other and a portion other than that is generated. In the case of (2), the length of the optical path from the LED 114b to the light emitting surface 114b is increased, the light diffusion is increased, and the region b of the light emitting surface 114b is reduced. It is essential to ensure the distance of the body 114 (in the Y direction on the paper surface), which is often inconvenient in design. Furthermore, in the case of (3), usually, only the diffusion processing of the light emitting surface 114b has a small amount of light diffusion, and an effect that suppresses unevenness of light intensity is often not seen. In particular, when a linear light source such as an LED is used as an automotive lighting device, it may be difficult to solve the problems of uneven light intensity and light flashing by measures (1) to (3) in terms of cost and space. Many.

<< Linear light source unit structure of the present invention >>
To solve this problem, the linear light source unit structure of the present invention (the first and second present inventions) has been solved by methods other than the above (1) to (3). Illustrate.

<< First Embodiment of the Present Invention >>
FIG. 1 shows a perspective view of an example of the structure of a linear light source unit structure 10 used as an automobile lighting device or the like. In the linear light source unit structure 10, a plurality of LEDs as point light sources 12 are arranged along the support member 13 in the lateral direction (the X direction in the drawing) as in the example of FIG. 5 (in FIG. 1). Illustrated with two LEDs 12). A plate-shaped light guide 14 is disposed in front of the light irradiation direction (the Y direction on the paper surface) of each LED 12 so that the thick portion is located. When attention is paid to one of the LEDs 12a, the irradiated light 15 is taken into the thickness 14a of the light guide 14, and the light is diffused into the region sandwiched by the arrows α1 and α2 while propagating through the inside as it is. 14b is irradiated to the outside. In FIG. 1, it is shown that the portion that emits light on the light emitting surface 14 b at this time is the region A.

Similarly, in the case of the other LED 12b, the irradiation light 16 is also diffused while propagating inside incorporated into the thickness 14a of the light guide 14 is emitted to the outside from the light emitting surface 14 b, the light-emitting surface 14b A portion that emits light is indicated by a region B.

However, the linear light source unit structure 10 of FIG. 1 is greatly different in that slits 20 and 21 are provided in the light guide 14. The slits 20 and 21 are holes penetrating the light guide 14 in the thickness direction, and the slits 20 and 21 are filled with an environmental atmosphere such as air. The slits 20 and 21 have a role of largely diffusing when the light irradiated from the LEDs 12a and 12b and transmitted through the light guide 14 passes therethrough. This will be described below with reference to a schematic view of the linear light source unit 10 of FIG. 1 viewed from above.

As shown on the left side of FIG. 2, the light emitted from the LED 12a is incident on the edge 14c of the light guide 14 while diffusing. The diffused light is indicated by five arrows α1 to α5 and diffuses between α1 and α2 (which may exceed the range of α1 to α2). Here, the light that becomes the optical axis is indicated by an arrow α4. The slit 20 has a substantially arc shape in which an edge 20a on which light is incident swells toward the LED 12a. When such a shape is used, most of the light is refracted and diffused when passing through the edge 20a except for the optical axis α4 that is incident in a normal line. The edge portion 20a has a curvature that allows light incident from the light source 12a to pass through the light emitting surface. Further, light close to the optical axis α4 is incident in a normal line, and is transmitted as it is with almost no refraction. The light guide 14 is made of a material having a higher refractive index than air, such as glass, and is largely refracted.

The light transmitted through the slit 20 passes through the hole 20c of the air layer as it is in a refracted and diffused state, and reaches the edge 20b on the light emitting surface 14b side (the lower side in the drawing). The edge portion 20b has a substantially arc shape that swells toward the light emitting surface 14b, and has a larger curvature than the edge portion 20a (the radius of curvature of the edge portion 20b is smaller). With such a shape, the light that diffuses at the edge 20a and passes through the hole 20c of the slit 20 is incident on the light guide 14 in a state where the edge 20b is close to the normal direction. The light passes through the edge 20b without being refracted. Then, it passes through the light guide 14 and reaches the light emitting surface 14b.

In the example of FIG. 5, light is emitted to the outside from the light emitting surface 114b and emits light. However, in the linear light source unit structure 10 of FIGS. Light diffuses (see arrow in FIG. 1).

FIG. 3 is an experimental example showing a state in which light is actually irradiated with an automotive lighting device using the linear light source unit structure 10 of FIGS. 1 to 2, and (a) shows the automotive lighting device as viewed from the front. (B) shows a cross-sectional view of (a) as viewed from above.

In FIG. 3 (a), the optical path from the LED 12 is indicated by a white cross, and in FIG. 3 (b), the optical path from the LED 12 is indicated by a white line (only the optical path is shown, and each white line indicates the light intensity. Not) As can be seen from this figure, it is understood that the light from the LED 12 is diffused by the slit 20.

<< Second Embodiment of the Invention >>
FIG. 4 shows a plan view of an example of the structure of a linear light source unit structure 50 used as an automobile lamp or the like. The positional relationship among the LED 52 as the light source, the light guide 50, and the light emitting surface 50b is substantially the same as that in the perspective view of FIG. Specifically, in the linear light source unit structure 50, a plurality of LEDs 52 are arranged in the horizontal direction (left and right direction on the paper surface) as in the example of FIG. 2 (illustrated by two LEDs 52 as in FIG. 2). A plate-shaped light guide 54 is disposed in front of the light irradiation direction (downward direction of the paper) of the LED 52 so that the thick portion is located, and the light emitted from the LED 52 is within the thickness of the light guide 54. The light is emitted from the light emitting surface 54b while propagating through the inside.

In the linear light source unit structure 50 of FIG. 4, slits 60, 61, 62 are provided in the light guide 54. The slits 60, 61, 62 are holes that penetrate the light guide 54 in the thickness direction, and the slits 60, 61, 62 are filled with an environmental atmosphere such as air. The slits 60, 61, and 62 sequentially reflect light irradiated from the LEDs 52a and 52b and transmitted through the light guide 54 in the substantially horizontal direction (X direction shown in FIGS. 1 and 5) in order to reduce the length of the optical path. It has a role of propagating to the light emitting surface 54b while extending.

The light emitted from the LED 52b shown in FIG. 4 is incident on the edge 54c of the light guide 54 and reaches the slit 62 while diffusing in the range of λ3 to λ4 (which may exceed the range of λ3 to λ4). To do. The slit 62 has a linear shape that is inclined to the right (inclined from the upper right to the lower left (having an oblique angle with respect to the optical axis of light (not shown)). Reflects to the left. Although not shown, some of the light λ3 to λ4 are not reflected at this time, but pass through the slit 62 as in the case of FIGS. 1 to 2 and reach the light emitting surface 54b from the slit 62 as it is. The light λ3 to λ4 reflected by the slit 62 arrives while diffusing to the left adjacent slit 61 arranged in the same shape, reflected to the light emitting surface 54b side, and further diffused to reach the light emitting surface 54b. In this linear light source unit structure 50, the light path in the light guide 54 is extended by adjacent slits inclined in the same shape, so that the light is diffused greatly and reaches the light emitting surface 54b to be emitted.

Next, paying attention to the LED 52a, similarly to the light emitted from the LED 52b, the light enters the edge 54c of the light guide 54, reaches the slit 61 while being diffused in the range of λ1 to λ2, and is reflected to the left side. To do. Although not shown, a part of the light λ1 to λ2 is not reflected at this time but is transmitted through the slit 61 and reaches the light emitting surface 54b as it is. The light λ1 to λ2 reflected by the slit 61 reaches the adjacent slit 60 arranged in the same shape while diffusing, reflects to the light emitting surface 54b side, diffuses, and reaches the light emitting surface 54b. As described above, in the linear light source unit structure 50, the light that is greatly diffused by a plurality of adjacent slits inclined in the same shape is emitted from the light emitting surface 54 b.

In the example of FIG. 4, the light emitted to the outside from the light emitting surface 54b is further diffused and diffused by the diffusion processing 63 as in the case of FIG. 2, and emitted from the light emitting surface 54b .

Although the linear light source unit structure in the present invention has been described above, the present invention is not limited to this, and other modifications, without departing from the spirit and teaching described in the claims and the description, etc. One skilled in the art will appreciate that improvements can be obtained.

10 Linear light source unit structure 12 Point light source (LED)
13 Support member 14 Light guide 14b Light emitting surface 20 Slit (hole)
23 Diffusion processing 50 Linear light source unit structure 52 Point light source (LED)
54 Light guide 54b Light-emitting surface 61, 62, 62 Slit (hole)
63 Diffusion processing

Claims (1)

In the linear light source unit structure that diffuses incident light by providing a hole between the light source side of the light guide member and the light emitting surface,
The shape of the hole is composed of two oppositely curved surfaces on the light source side and the light emitting surface side. The surface on the light source side has a curvature that transmits light incident from the light source to the light emitting surface side. the curvature of the side surfaces much larger than the curvature of the surface on the light source side,
The surface on the light source side of the hole has a substantially arc shape that swells toward the light source side,
The surface of the hole on the light emitting surface side has a substantially arc shape that swells toward the light emitting surface .