JP5693096B2 - Lighting device - Google Patents

Description

  The present invention relates to a lighting device having high illuminance and wide light distribution characteristics.

  Many lighting devices are installed outdoors for traffic safety and crime prevention. In the case of a crime prevention light, as a lighting effect for crime prevention, a brightness that gives an outline of the face of a person 4 meters ahead or a brightness that shows the behavior and posture of a pedestrian 4 meters ahead is often desired.

  Further, in a lighting device such as a security light, it is desired that the above illuminance standard is satisfied to a farther distance without increasing the output of the light source. This makes it possible to save energy and reduce the number of lighting devices installed, and can efficiently perform traffic safety and crime prevention.

  In general, a lighting device such as a security light is often attached to a utility pole or pole at a height of 4.5 m. In this case, for example, the vertical illuminance at a position 1.5 m from the road at a location 10 m away from the lighting device is determined by the luminous intensity in a substantially horizontal direction of 73 ° from the lighting device. Since the illuminance decreases in inverse proportion to the square of the distance, it is difficult to obtain the illuminance that satisfies the above illuminance standard unless the luminous intensity in the wide angle direction of the orientation is increased by controlling the light distribution characteristics of the lighting device. is there.

  As a technique for controlling the light distribution characteristics of the lighting device, it is disclosed in Japanese Unexamined Patent Application Publication No. 2000-331504 (Patent Document 1) or Japanese Unexamined Patent Application Publication No. 2009-252375 (Patent Document 2). There is an illuminated lighting device.

  In the street lighting apparatus disclosed in Patent Document 1, a transparent cover that houses a fluorescent lamp is provided with a brism cut portion having a plurality of prisms extending in a direction perpendicular to the street long axis direction, A reflector is provided on the upper part of the translucent cover. And the light radiated | emitted diagonally downward and the side from the said fluorescent lamp permeate | transmits the transparent part of the said translucent cover as it is, and goes to the said street long-axis direction. On the other hand, when the light emitted downward from the fluorescent lamp passes through the prism cut portion of the translucent cover, it is bent toward the street long axis direction. The light emitted obliquely upward and upward from the fluorescent lamp is specularly reflected by the reflecting plate, passes through the transparent portion of the translucent cover, and travels in the street long axis direction.

  As described above, the light distribution characteristics are controlled by combining the reflector, the transparent portion of the translucent cover, and the prism cut portion of the translucent cover in a timely manner, and the light intensity in the horizontal direction, that is, the street long axis direction. Has increased.

  In addition, the illumination device disclosed in Patent Document 2 includes a lens plate disposed to face the semiconductor light source. The lens plate has a lens light incident surface facing the semiconductor light source, and the lens light incident. A lens light exit surface formed through the lens thickness from the surface, and distributes light from the semiconductor light source along the longitudinal direction to either the lens light incident surface or the lens light exit surface Forming a first lens portion made of a prism that distributes light from the semiconductor light source along the short direction perpendicular to the longitudinal direction to the other of the lens light incident surface and the lens light exit surface. A second lens portion made of a cylindrical lens is formed.

  However, the conventional lighting device that controls the light distribution characteristics has the following problems.

  That is, in a lighting device installed on a road or the like, it is important to control the light distribution in two directions parallel to the road traveling direction and the width direction.

  However, the prism of the bristle cut portion provided on the translucent cover in the street lighting device disclosed in Patent Document 1 has a shape that is extended only in one direction orthogonal to the street long axis direction. . Therefore, for example, there is a problem that only the light distribution characteristic in one direction such as the road traveling direction, that is, the street long axis direction can be controlled.

  Therefore, in order to control the light distribution in the above two directions, a reflecting member called a reflector must be used in combination, which causes another problem that the number of parts increases. In addition, there is a method of using the housing of the lighting device as the reflector, but it becomes impossible to design a free housing.

  Further, in the illumination device disclosed in Patent Document 2, the light distribution in the road traveling direction and the width direction can be controlled by providing a prism shape or a concave lens shape on both surfaces of the optical element formed of a lens plate. Although it is possible, it is necessary to provide the lens plate dedicated to light distribution control, and there is a problem that the number of parts increases.

JP 2000-331504 A JP 2009-252375 A

  Therefore, an object of the present invention is to provide an illumination device that can optimize light distribution characteristics in two directions with a simple configuration without using an additional optical member.

In order to solve the above problems, the lighting device of the present invention is:
Multiple light sources;
An optical member having an incident surface on which light emitted from each of the light sources is incident, and an exit surface for emitting the light incident from the incident surface;
A first prism group and a second prism group formed on the incident surface of the optical member and including a plurality of prisms arranged in parallel;
The first prism group includes:
Arranged at a position facing each of the plurality of light sources,
The extending direction of each prism is a direction along a curve ,
Upper Symbol Each prism, the light beam from the incident the light source, as well as wide angle to the array direction of the center of curvature of the light source and the curve is adapted to the condenser in a direction crossing the arrangement direction
The second prism group is:
Arranged at a position facing each other between the light sources,
The extending direction of each prism is the arrangement direction along a straight line,
Each of the prisms is characterized in that the incident light from the light source is narrowed in a direction perpendicular to the extending direction of the prism .

  According to the above configuration, the first prism group including the plurality of prisms extending in the direction along the curve and arranged in parallel is formed on the incident surface of the light from the light source in the optical member. The incident light from the light source is widened in the arrangement direction of the light source and the center of curvature of the curve, and is condensed in a direction intersecting the arrangement direction.

Therefore, from the light source incident on the first prism group without using another additional optical member, a simple configuration that simply forms the first prism group on the incident surface of the optical member. Can be condensed in another direction different from the one direction. That is, it becomes possible to optimize the light distribution characteristics in two different directions.
At this time, since the first prism group is formed at a position facing each of the plurality of light sources, the first prism group can be used with respect to strong light emitted straight from the light source. Thus, it is possible to widen the angle in the one direction and collect light in the other direction. Therefore, the light distribution characteristics in two different directions can be optimized more effectively.
Furthermore, since the second prism group that narrows the incident light in a direction orthogonal to the extending direction of the prism by the linearly arranged prism is provided, the second prism group is separated from the light source. By installing at a distant position, a light beam having a large emission angle from the light source can be narrowed by the second prism group, and extinction due to total reflection or the like is reduced to increase the amount of extracted light. Can do.
In that case, if the condensing direction by the first prism group and the narrowing direction by the second prism group are set in the same direction, the light distribution characteristic in the direction is more effectively improved. Can be controlled.
Further, the first prism group is disposed at a position facing each of the plurality of light sources in the optical member, while the second prism group is disposed at a position facing each light source. Thus, it is possible to optimize the light distribution characteristics in two different directions and increase the efficiency of light utilization.

In the lighting device of one embodiment,
The curve representing the extending direction of the prism is a part of a circular arc,
The center of the arc is set at a position different from the optical axis of the light source.

  According to this embodiment, the curve representing the extending direction of the prism is part of a circle. Therefore, the formation of the first prism group with respect to the incident surface of the optical member can be facilitated.

  Further, the center of the arc is set at a position different from the optical axis of the light source. Therefore, the light from the light source incident on each prism can be reliably widened in the one direction.

In the lighting device of one embodiment,
The plurality of prisms have a partial shape of a plurality of circular arcs arranged concentrically,
The center of the arc is set at a position different from the optical axis of the light source.

  According to this embodiment, the plurality of prisms have a partial shape of a plurality of circular arcs arranged concentrically. Therefore, the formation of the first prism group on the incident surface of the optical member can be further facilitated.

  Further, the center of the arc is set at a position different from the optical axis of the light source. Therefore, the light from the light source incident on each prism can be reliably widened in the one direction.

In the lighting device of one embodiment,
A plurality of centers of the arc are set for one first prism group.

  According to this embodiment, a plurality of arc centers are set for one first prism group. Therefore, the light emitted from the light source in any direction is efficiently widened in the one direction by any one of a plurality of the prisms that form a part of an arc centered on a plurality of centers. The light is condensed in the other direction.

  As is clear from the above, the illumination device according to the present invention includes a first prism including a plurality of prisms arranged in parallel and extending in a direction along a curve on a light incident surface of a light source in an optical member. Forming a group so that the light beams from the light source incident thereon are widened in the direction of arrangement of the light source and the center of curvature of the curve and condensed in a direction crossing the arrangement direction. As a result, it is possible to optimize the light distribution characteristics in two different directions.

  Furthermore, it is possible to optimize the light distribution characteristics in two different directions only by the optical member. Therefore, the light distribution characteristics in the two directions can be optimized with a simple configuration without using an additional optical member such as a reflector, and the cost can be reduced.

It is a figure which shows the external appearance in the illuminating device of this invention. It is a figure which shows the installation state to the road of the illuminating device shown in FIG. It is explanatory drawing of the prism pattern formed in the optical member in FIG. FIG. 4 is an enlarged plan view of one prism group in FIG. 3. It is sectional drawing which shows the structure of the prism group shown in FIG. FIG. 5 is a ray diagram illustrating a state in which light emitted from a light source 3 passes through each prism of the prism group illustrated in FIG. 4. It is a figure which shows the arrival position on the road of the light ray in FIG. It is sectional drawing which shows the structure of the other prism group in FIG. It is a figure which shows the arrival position on the road of the light ray in FIG. It is a figure which shows schematic structure of the illuminating device different from FIG. It is sectional drawing in the illuminating device shown in FIG. It is a figure which shows the prism pattern formed in the optical member in FIG. It is a figure which shows the simulation result of the light distribution characteristic in the illuminating device shown in FIG.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

-1st Embodiment FIG. 1: is a figure which shows the external appearance in the illuminating device of this Embodiment. The illumination device 1 includes an optical member 2, a substrate on which a light source 3 is mounted, a power supply unit (not shown) that supplies power to the light source 3, and a box 5 for supporting the substrate. . Here, the optical member 2 constitutes a part of the box 5 and functions as a translucent cover.

  Here, the three axes that define the three-dimensional space of the illuminating device 1 are defined as follows: the longitudinal direction of the illuminating device 1 is the y axis, and the short direction of the illuminating device 1 is the x axis. Set the output direction to the z-axis. A plurality of light sources 3 are mounted on the substrate. In the present embodiment, an example in which four light sources 3 are mounted in the y direction is shown as an example. As the light source 3, an LED (Light Emitting Diode) or the like can be used.

  As shown in FIG. 2, the lighting device 1 has a longitudinal direction (y direction) and a short direction (x direction) of the lighting device 1 as a width direction Y ′ and a traveling direction X ′ of the road 6, respectively. Installed. Moreover, the illuminating device 1 is arrange | positioned with a certain angle (eta) with respect to a perpendicular direction, as shown in FIG. In this case, the angle η is appropriately changed and set depending on the design required for the lighting device 1, the box shape, and the like. Alternatively, in order to efficiently spread the light emitted from the lighting device 1 in the ± Y ′ direction on the road 6, it is appropriately changed and set. Here, the Y ′ direction is a direction orthogonal to the X ′ direction, which is the traveling direction of the road 6, and is the width direction of the road 6, as shown in FIG. 2.

  A prism pattern is formed on the inner surface of the optical member 2. Hereinafter, the prism pattern will be described with reference to FIG.

  FIG. 3 shows the prism pattern formed on the inner surface of the optical member 2 together with the positional relationship with the light source 3. As shown in FIG. 5 (a), the optical member 2 has a “U” shape in the xz cross section, and the opening is closed by the plate member 7. A substrate 4 on which the light source 3 is mounted is disposed on the inner surface of the plate member 7. Thus, the optical member 2 and the plate member 7 constitute a box 5.

  In FIG. 3, on the inner surface of the optical member 2 facing the plate member 7, a prism group 8 and a prism group 9 having different prism patterns are alternately arranged in the y direction. 8 is formed immediately above the light source 3. Each of the prism group 8 and the prism group 9 includes a plurality of prisms arranged in parallel. In the drawing, solid lines in the prism group 8 and the prism group 9 indicate intermediate positions between the prisms adjacent to each other (that is, valleys of the prisms).

  The prism group 8 includes a plurality of prisms formed in a curved shape. FIG. 4 shows an enlarged plan view of one prism group 8. The prism pattern of the prism group 8 illustrated in FIG. 4 is a pattern that is symmetric with respect to the intersection of the center of the light source 3 and the axis (optical axis) passing through the center of the prism group 8 and the formation surface of the prism group 8 in the optical member 2. have. Each prism extends so as to be a part of an arc centered on the points 10a and 10b located on both sides of the prism group 8, and is formed concentrically at an equal interval.

  FIG. 5 shows the configuration of the prism group 8. However, FIG. 5A shows an xz section passing through the light source 3 of the illumination device 1. FIG. 5 (b) shows an enlarged surface of the prism portion in FIG. 5 (a).

  On the inner surface of the optical member 2 facing the plate member 7, a prism group 8 is formed which is composed of a plurality of prisms 11 formed at equal intervals in a concentric circle centered on the points 10a and 10b. In the present embodiment, as an example, a case where the prism group 8 includes 16 prisms 11 is shown. The center of the prism group 8 is set so as to be positioned immediately above the center of the light source 3 so that the top of the light source 3 is just the valley of the prism 11 (that is, the optical axis of the light source 3 is just the valley of the prism 11). Set to pass through). The prism group 8 has a symmetric shape with respect to the intersection of the optical axis of the light source 3 and the surface of the optical member 2 where the prism group 8 is formed. The two inclination angles Ψ1, Ψ2 in each prism 11 are set to the same angle.

  On the other hand, the prism group 9 is formed by arranging a plurality of prisms extending linearly in the x direction in parallel at equal intervals.

  FIG. 6 is a ray diagram showing a state in which light emitted from the light source 3 passes through each prism 11 of the prism group 8.

  FIG. 6A shows a ray diagram in the zx section passing through the light source 3. In FIG. 6A, a part of the light emitted from the light source 3 enters the optical member 2 via the prism 11 formed on the incident surface of the optical member 2. The angle of the prism surface of each prism 11 is set so as to increase the radiation angle θ of the reaching light beam, and the light transmitted through each prism 11 is the exit surface of the flat optical member 2 on which nothing is formed. Then, the light is refracted again and emitted from the lighting device 1 to illuminate the road 6. In this way, by forming the arc-shaped prism 11 symmetric with respect to the intersection of the optical axis of the light source 3 and the formation surface of the prism group 8 in the optical member 2 on the optical member 2, the longitudinal direction of the prism 11 ( It is possible to widen the light distribution in a direction orthogonal to the extending direction.

  FIG. 6B is a ray diagram of the prism group 8 in plan view (xy plane). In FIG. 6B, a light beam L indicated by a solid line represents a path of light passing through the arc-shaped prism 11. On the other hand, a light beam L ′ indicated by a broken line represents a light path when it is assumed that the prism is linearly formed in the y direction. As can be seen from FIG. 6B, by forming the prism pattern in a curved shape, the path of the light beam is the direction in which the center 10b of the prism pattern forming an arc is set at the incident position 12 to the optical member 2. To be bent.

  The function of the concentric arc prism 11 centered on the point 10b has been described above, but the function of the concentric arc prism centered on the point 10a is the same.

  That is, as shown in FIGS. 6A and 6B, by arranging the prism group 8 at a position immediately above the light source 3, the light distribution of the light emitted from the light source 3 is changed to each of the components constituting the prism group 8. While the angle is widened in the arrangement direction (x direction) between the centers 10a and 10b of the prism 11 and the light source 3, the light can be condensed in a direction (y direction) orthogonal to the arrangement direction.

  FIG. 7 shows the arrival positions on the road 6 with respect to the light beam L and the light beam L ′ in FIG. 6. As can be seen from FIG. 7, when it is assumed that the prism pattern is formed in a straight line in the y direction, the light reaches outside the range on the road 6 to be originally illuminated. However, as in the present embodiment, by forming the prism pattern in an arc shape, it is possible to allow light to reach the area to be illuminated on the road 6 and to improve the light utilization efficiency.

  The shape of the prism 11 constituting the prism group 8 is symmetrical with respect to the intersection of the optical axis of the light source 3 and the surface of the optical member 2 where the prism group 8 is formed, and is located on both sides of the prism group 8. The simple shape of the circular arc centered on the points 10a and 10b facilitates the formation of the optical member 2 and illumination characteristics even when the optical member 2 and the light source 3 are misaligned. It is possible to realize the lighting device 1 in which the change is difficult.

  In the present embodiment, the prism group 8 includes a plurality of prisms 11 having the same shape, and the optical axis of the light source 3 and the optical member from the viewpoint of ease of formation of the optical member 2 and consideration of tolerances. 2 are arranged so as to have a symmetrical shape with respect to the intersection with the formation surface of the prism group 8. However, the present invention is not limited to such shapes and arrangements, and a plurality of types of prisms having different inclination angles and apex angles may be used, or at the intersection of the optical axis of the light source 3 and the formation surface of the prism group 8 in the optical member 2. In contrast, the prism group 8 may be configured by arranging a plurality of prisms in an asymmetric shape. The light distribution can be precisely controlled by changing the inclination angle of each prism.

  As described above, by using the prism group 8 in the present embodiment, the light emitted from the light source 3 is widened with respect to the traveling direction (X ′ direction) of the road 6 and the width of the road 6 is increased. The light can be condensed in the direction (Y ′ direction). Therefore, it is possible to realize an illumination device having a wide light distribution characteristic and high light use efficiency.

  FIG. 8 shows the configuration of the prism group 9. However, FIG. 8A shows a part of a yz section passing through the light source 3. FIG. 8B shows an enlarged surface of the prism portion in FIG.

  Each prism 13 constituting the prism group 9 is formed in a straight line extending in the x direction (that is, the traveling direction of the road 6) in FIG. FIG. 8A shows a case where the prism group 9 is formed by eleven prisms 13 as an example.

  As shown in FIG. 8B, the prisms 13 constituting the prism group 9 have the same cross-sectional shape and are arranged at an equal pitch. Further, the two inclination angles φ1 and φ2 in each prism 13 are set so as to satisfy the relationship φ1> φ2. Further, the inclination angles φ1 and φ2 are set so that the incident angle of the light beam from the light source 3 that reaches the light is a condition for total reflection. Thus, the light rays from the light source 3 incident on the prism surfaces of the respective prisms 13 are totally reflected by the prism surfaces, so that the direction of the light rays changes greatly as the light rays L indicated by solid lines. In the present embodiment, since the two inclination angles φ1 and φ2 of each prism 13 are set asymmetric, the direction of the light beam distributed by the prism group 9 is as shown in FIG. , And is focused toward the xz plane which generally includes the optical axis of the light source 3. That is, the angle is narrowed in the y direction orthogonal to the extending direction x of the prism 13. A light beam L ′ indicated by a broken line indicates a light beam when it is assumed that the incident surface of the optical member 2 is a flat surface (that is, the prism group 9 is not formed).

  A light beam having a large emission angle incident on a position away from the light source 3 has a relatively low intensity, and is easily lost due to reflection on the inner surface of the optical member 2 or total reflection on the surface. However, in the present embodiment, the prism group 9 having the above-described configuration is arranged at a position away from the light source 3, and the direction of the light beam having a large emission angle from the light source 3 incident on each prism 13 is set in the y direction. By narrowing the angle, the amount of light that can be extracted from the optical member 2 can be increased, and the light utilization efficiency can be improved.

  FIG. 9 shows the arrival positions on the road 6 with respect to the light beam L and the light beam L ′ in FIG. 8. When the prism group 9 is not formed on the optical member 2, the light beam L ′ is not focused in the y direction, and thus reaches a position off the range to be illuminated on the road 6. On the other hand, when the prism group 9 is formed, the light L is changed to effective light for illuminating the area to be illuminated on the road 6 by the action of each prism 13. Thus, the illumination device 1 that can efficiently illuminate a desired region on the road 6 by the light collecting function of the prism group 9 can be realized.

  Further, the light distribution of the light passing through the prism group 9 can be controlled to some extent independent of the light passing through the prism group 8, so that the degree of freedom in illuminance distribution design is increased and a desired illuminance distribution is obtained. It becomes easy.

  Further, the prism group 8 and the prism group 9 can set the height and size of the prisms 11 and 13 to about the size of the light source 3 by using a plurality of prisms 11 and 13. Thereby, thickness reduction and size reduction of the illuminating device 1 are realizable.

  As the material of the optical member 2, for example, an acrylic resin, polystyrene resin, methacrylic resin, polycarbonate resin, glass, or the like that has good transparency with respect to the visible light region and a large transmittance may be used.

  As described above, according to the illuminating device 1, light distribution from the light source 3 is controlled by the prism group 8 and the prism group 9 formed on the optical member 2.

  In that case, the prism group 8 is provided at a position where the light intensity is high near the light source 3, and the light from the light source is transmitted to the centers 10 a and 10 b of the prisms 11 constituting the prism group 8 and the light source 3. And the light is condensed in a direction perpendicular to the arrangement direction (y direction). That is, it has functions of widening the light in the traveling direction X ′ and condensing in the width direction Y ′ with respect to the traveling direction X ′ and the width direction Y ′ orthogonal to each other on the road 6. . Therefore, the traveling direction X of the road 6 can be achieved with a simple configuration in which the prism group 8 is formed immediately above the light source 3 on the inner side of the emission surface of the optical member 2 and without using another additional optical member such as a reflector. It is possible to optimize the light distribution characteristics in two directions, 'and the width direction Y of the road 6'.

  On the other hand, the prism group 9 narrows a relatively weak light beam emitted in the wide-angle direction out of the light emitted from the light source 3 in the y direction orthogonal to the extending direction of the prism 13. . That is, it has a function of condensing light in the width direction Y ′ of the road 6. Necessary characteristics required for road lights can be achieved only by the function of the prism group 8. However, by further providing the prism group 9, it is possible to realize the power-saving lighting device 1 with higher light utilization efficiency.

  At this time, the centers 10 a and 10 b of the arc-shaped prisms 11 constituting the prism group 8 are set at positions different from the optical axis of the light source 3. Therefore, the light from the light source 3 incident on each prism 11 can be reliably widened in the x direction. If the center of the prism 11 is set on the optical axis of the light source 3, the light from the light source 3 incident on each prism 11 is widened in all directions around the center of the prism 11. Therefore, it is not possible to widen the angle in one direction.

  Further, two (10a, 10b) are set on both sides of the center 10 of the arc-shaped prism 11 constituting the prism group 8 with respect to one prism group 8. Therefore, the light emitted from the light source 3 with a directional component toward the center 10a is widened in the x direction and condensed in the y direction by the arc-shaped prism 11 centered on the point 10a. Is called. On the other hand, the light emitted from the light source 3 having a directional component toward the center 10b side is widened in the x direction and collected in the y direction by the arc-shaped prism 11 centered on the point 10b. Light is done. Thus, the light emitted from the light source 3 in all directions is efficiently widened and condensed.

  Further, since the prism groups 8 and 9 are formed on only one surface of the optical member 2, the optical member can be easily formed.

  Further, when the prism groups 8 and 9 are formed on the optical member 2 constituting the box 5 of the lighting device 1, the prism groups 8 and 9 are formed on the inner side that is not exposed to the external environment. Adhesion and wear of the prisms 11 and 13 can be prevented. Therefore, it is possible to realize the lighting device 1 with little deterioration in optical characteristics.

-2nd Embodiment FIG. 10: shows schematic structure of the illuminating device 21 in this Embodiment. However, FIG. 10A is a perspective view seen from the light emitting side, and FIG. 10B is a plan view seen from the light emitting side. The illuminating device 21 has two substrates 24 on which the light source 23 is mounted, and the two substrates 24 are spaced apart from each other and arranged in parallel. FIG. 10 shows, as an example, a case where four light sources 23 are mounted on each substrate 24 at an equal pitch and a total of eight light sources 23 are provided.

  The optical member 22 on which the substrate 24 is installed has a central portion, that is, a portion between two substrates 24 arranged in parallel when viewed from the side from which light is emitted. A portion where the substrate 24 is disposed has a shape that swells in a racetrack shape.

  In FIG. 11, the cross section which shows the structure of this illuminating device 21 is shown. However, FIG. 11 (a) is a cross-sectional view taken along the line AA 'in FIG. 10 (b). FIG. 11B is a cross-sectional view taken along the line BB ′ in FIG.

  As can be seen from FIG. 11A, the optical member 22 has a symmetrical shape with respect to the center line (dashed line). In addition, a space is provided between the light source 23 and the optical member 22 in the bulging portion around the periphery, and two optical members 2 (see FIG. 5) in the first embodiment are arranged in parallel. It can be regarded as a structure. In addition, the light emission surface 25 of the optical member 22 is formed so as to have a slope that is higher on the center line side (center depression side) and lower toward the outside. In this way, by inclining the light emission surface 25, it becomes easy to widen the angle toward the outside of the inclined side, that is, the center line in the present embodiment.

  Further, as can be seen from FIG. 11 (b), the optical member 22 has a convex shape in which the central portion in the longitudinal direction is bulged, and has a symmetrical shape with respect to a center line (dashed line) 26. . On the other hand, the substrate 24 on which the light source 23 is mounted has a substantially flat surface, and the distance from the light source 23 to the optical member 22 is the longest at the location of the center line 26 and decreases as the distance from the center line 26 increases. .

  FIG. 12 shows a prism pattern formed on the inner surface of the optical member 22 opposite to the light exit surface 25.

  Just above the light source 23 (not shown), similarly to the prism group 8 in the first embodiment, an arc-shaped prism is formed on both sides of the intersection of the optical axis of the light source 23 and the prism forming surface of the optical member 22. A prism group 27 is formed. Here, in the present embodiment, two light sources 23 are installed on one side with respect to the center line 26 as shown in FIG. Therefore, two prism groups 27 are also formed on one side with respect to the center line 26 correspondingly. Among them, the width in the y direction of the prism group 27 a closer to the center line 26 is formed wider than that of the prism group 27 b far from the center line 26. Furthermore, the prism patterns in the prism groups 27 a and 27 b are asymmetrical patterns with respect to the intersection of the optical axis of the light source 23 and the prism forming surface of the optical member 22. The symmetry of this prism pattern is determined by the positional relationship between the surface on which the prism groups 27a and 27b are formed and the light source 23, and is appropriately set to satisfy desired characteristics.

  Similar to the prism group 9 in the first embodiment, between the prism group 27a and the prism group 27b and outside the prism group 27b, the optical member 22 travels in the x direction (width direction), that is, along the road 6. A prism group 28 in which linear prisms extending in the direction X ′ are formed is formed.

  FIG. 13 shows a simulation result of the light distribution characteristics in the illumination device 21 of the present embodiment. In FIG. 13, the solid line indicates the light distribution characteristic in the xz plane (see FIG. 11A), and the broken line indicates the light distribution characteristic in the yz plane (see FIG. 11B).

  Here, the light distribution of the light emitted from the light source 3 is assumed to be a Lambertian distribution. The apex angle of the prisms formed in the prism group 27a and the prism group 27b is set to 50 °, and the inclination angle of the base is set to 65 °. Further, the width of the bottom surface of the prism is set to 1 mm, and the arrangement pitch is set to 1.3 mm.

  Also, the apex angle of the prisms formed in the prism group 28 is set to 60 °, and the inclination angles of the bases are set to 65 ° and 55 °. And when installing the illuminating device 21 in the road 6, it installs so that the inclination-angle 55 degree side may become an upper side of the inclination-angle 65 degree side. The method of setting the inclination angle varies depending on the inclination of the illumination device 21 and the angle η, and is appropriately changed and set so as to illuminate the road 6 efficiently. Further, the width of the bottom surface of the prism is set to 1.0 mm, and the pitch of the array is set to 1.3 mm.

  The light distribution characteristic (solid line) in the xz plane in the illumination device 21 shown in FIG. 13 shows the characteristic that the maximum intensity is in the 0 ° direction in the same manner as the light source 23 in the absence of the optical member 22. Since light is spread by the action of each prism formed in the 22 prism groups 27a and 27b, a wide-angle light distribution having a peak in the vicinity of ± 60 ° is realized. Further, the light distribution characteristic (broken line) in the yz plane is that light is focused in the yz plane by the action of each prism formed in the prism group 27a, 27b, 28 of the optical member 22, and therefore the light distribution The distribution is narrower than the Lambertian distribution.

  Here, the values of the average horizontal plane illuminance and the minimum vertical plane illuminance when the lighting device 1 according to the first embodiment is applied to a security light are 3.2 lx and 0.55 lx, respectively. The total number of light beams emitted from the light source 3 is 7000 lm. Note that the number of light beams is set by changing timely according to the size of the light beam required for the lighting device 1. Regarding the brightness of the security light, the standard of brightness that can recognize the behavior and posture of a pedestrian 4 meters ahead is cleared.

  In this case, the lighting device 1 has a height (H) of 4.5 m, an arrangement interval (D) of the lighting device 1 of 14 m, and an x direction of the lighting device 1 as shown in FIG. It is installed so as to be parallel to the traveling direction X ′ of the road. Further, the road width (W) is set to 5 m, and a perpendicular line passing from the center of the lighting device 1 to a plane including the road 6 passes through the road 6.

  The average horizontal plane illuminance indicates an average horizontal plane illuminance when a road area of 14 m × 5 m sandwiched between two lighting devices 1 is illuminated by the lighting devices 1 arranged at both ends thereof. The minimum vertical surface illuminance was calculated as the illuminance value of the surface perpendicular to the road 6 at a position 14 m away from the lighting device 1 in the X ′ direction and 1.5 m in the Z ′ direction.

  As described above, in the illuminating devices 1 and 21 in each of the above-described embodiments, the prism groups 8 and 9; It is possible to optimize the light distribution characteristics by controlling the light distribution characteristics in two directions orthogonal to each other on the road 6 without using other optical members. Therefore, it is possible to realize a road light that can clear specifications required for road lighting at a high level.

  In addition, it is not necessary to use the casing of the lighting devices 1 and 21 as a reflector, and a compact lighting device can be realized.

  The optical members 2 and 22 on which the prism groups 8 and 9; 27a, 27b and 28 are formed can be used as a translucent cover for protecting the light sources 3 and 23 from rain and dust. In that case, the light distribution characteristics in the above two directions can be optimized without adding an optical member dedicated to light distribution, and the low-cost lighting devices 1 and 21 can be realized.

  Further, since the prism groups 8, 9; 27a, 27b, 28 need only be formed on one surface of the optical members 2, 22, the light distribution characteristics can be optimized according to the shape of the optical members 2, 22. It becomes easy and it becomes easy to implement | achieve the illuminating devices 1 and 21 which do not impair design property.

  Moreover, the illuminating devices 1 and 21 in each of the above embodiments can be widely used for outdoor illumination such as crime prevention lights, street lights, road lights, and park lights, and other illuminations.

  The lighting device of the present invention is useful for optimizing light distribution characteristics in two directions with a simple configuration, and is used for outdoor lighting such as crime prevention lights, street lights, road lights, and park lights, and various illuminations. Can do.

1, 21 ... Lighting device,
2, 22 ... optical member,
3, 23 ... Light source,
4, 24 ... substrate,
5 ... Box,
6 ... road,
7: plate member,
8, 9, 27a, 27b, 28 ... Prism group,
10a, 10b ... dots,
11, 13 ... Prism,
12: Light incident position,
25: Light exit surface.

Claims (4)

Multiple light sources;
An optical member having an incident surface on which light emitted from each of the light sources is incident, and an exit surface for emitting the light incident from the incident surface;
A first prism group and a second prism group formed on the incident surface of the optical member and including a plurality of prisms arranged in parallel;
The first prism group includes:
Arranged at a position facing each of the plurality of light sources,
The extending direction of each prism is a direction along a curve ,
Upper Symbol Each prism, the light beam from the incident the light source, as well as wide angle to the array direction of the center of curvature of the light source and the curve is adapted to the condenser in a direction crossing the arrangement direction
The second prism group is:
Arranged at a position facing each other between the light sources,
The extending direction of each prism is the arrangement direction along a straight line,
The illumination device according to claim 1, wherein each of the prisms narrows an incident light beam from the light source in a direction perpendicular to an extending direction of the prism . The lighting device according to claim 1.
The curve representing the extending direction of the prism in the first prism group is a part of an arc.
The center of the arc is set at a position different from the optical axis of the light source. The lighting device according to claim 1 or 2,
The plurality of prisms in the first prism group have a partial shape of a plurality of circular arcs arranged concentrically,
The center of the arc is set at a position different from the optical axis of the light source. In the illuminating device of Claim 2 or Claim 3,
The center of the said circular arc is set with respect to one said 1st prism group, The illuminating device characterized by the above-mentioned.

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