JP6706183B2 - Optical element - Google Patents

Description

The present invention relates to a translucent optical element including a reflective surface.

Patent Document 1 describes a vehicle lighting device that can appropriately irradiate a desired light distribution irradiation pattern. The vehicle lighting device of Patent Document 1 has a lens portion that changes incident light from an LED by refraction and emits the light, and an upper side that reflects and emits the incident light from the LED by an upper reflecting surface formed above the lens portion. The optical member includes a reflector portion and a lower reflector portion that reflects incident light from the LED on a lower reflection surface formed below the lens portion and emits the reflected light. A refraction portion that refracts the incident light from the LED downward and guides it to the outside of the illumination optical path is provided below the incident surface of the lens portion. Further, due to the refraction of the entrance surface and the exit surface of the lens part, the emission angle in the vertical direction is changed so as to be close to parallel light, and the light is emitted. It is configured to be directed obliquely forward and downward and to illuminate a region below the horizontal position of the lighting device. This makes it possible to appropriately irradiate a desired area required for the fog lamp or the like.

JP, 2010-212021, A

However, the illumination device using the refraction of the lens portion has a limit in controlling the light distribution.

In recent years, an optical element capable of controlling the light distribution more flexibly has been demanded.

One embodiment of the present invention is a translucent optical element including a reflective surface that reflects light entering from the rear toward the front. The reflecting surface of this optical element is a first reflecting surface that extends in one direction when viewed from the front and reflects light in a direction away from the optical axis of the light in the area until the light enters the optical element. And a second reflecting surface that extends in one direction when viewed from the front and reflects light in a direction intersecting the optical axis thereof.

By passing the light from the light source through this optical element, the light distribution can be controlled more flexibly.

The figure which shows the schematic structure of a lighting system. Sectional drawing which shows the structure of an illuminating device from the direction orthogonal to a longitudinal direction. The perspective view which extracts and shows an optical element and a light source. FIG. 3 is a perspective view showing an optical element including a prism on a part of an irradiation surface. It is a figure which shows another example of an irradiation surface, FIG.5(a) has an irradiation surface containing a lenticular, and FIG.5(b) has an irradiation surface containing a wrinkle. Sectional drawing which shows the structure of a different illuminating device.

FIG. 1 shows an example of a lighting system. The illumination system 1 is a signboard illumination system used for externally illuminated signboards and the like, and is capable of illuminating a signboard having a relatively large area (large size) with little unevenness in illuminance. The lighting system 1 includes a lighting device 10 arranged above the signboard 3 so as to illuminate the signboard 3 which is vertically stood in FIG. 1, and a frame 6 which supports them. The frame 6 is fixed to the ground 5. The illumination device 10 includes a light source 11 and an optical element 20 arranged in front of the light source 11. FIG. 1 shows the illuminating device 10 from the side (end face) direction, and the illuminating device 10 is a rod-shaped or columnar device extending (long) in a direction perpendicular to the paper surface of FIG. 1. The illuminating device 10 is arranged downward so that the optical axis 19 extending forward from the light source 11 is parallel to the signboard 3 and faces the direction of the ground 5, and illuminates the signboard 3 with downward light 15 as a whole. In this embodiment and also in other embodiments, the direction in which the light 15 is emitted, that is, the lower side of FIG. 1 and FIG. 2 is referred to as the front, and the upper side is referred to as the rear.

The light (light flux) 15 output from the lighting device 10 is close to the central component 16 that diffuses from the center 21 of the lighting device 10 along the optical axis 19 toward the front (lower side) and the signboard 3 of the lighting device 10. The first component 17 output from the side (inside) 22 toward the upper half 3a of the signboard 3 and the lower part of the signboard 3 across the optical axis 19 from the side (outside) 23 far from the signboard 3 of the lighting device 10. (Lower half) and second component 18 output towards 3b. Therefore, the signboard 3 is illuminated by the first component 17 of the light flux 15 on the upper half 3a close to the lighting device 10, particularly on the upper side thereof, and by the central component 16 from the upper half 3a to the lower half 3b. The lower half 3b far from the illuminating device 10 where the central component 16 is weakened is illuminated by the central component 16 and the second component 18. Therefore, the lighting device 10 can illuminate the entire surface of the signboard 3, that is, from the top to the bottom with substantially uniform illuminance.

As a signboard illumination, a method of installing a plurality of spotlights is known. With this method, since the central portion of the spotlight becomes bright and the surroundings become dark, it is very difficult to uniformly illuminate the entire surface of the irradiation target, and uneven illuminance occurs. Further, since it is necessary to increase the illuminance in the dark part, it is necessary to set the wattage of the lighting device to be high, and the irradiation efficiency is poor.

There is also known a method of arranging a fluorescent lamp and a reflector along the upper edge of the signboard to illuminate the signboard as an irradiation target surface. The reflection plate is in the shape of a umbrella on the upper part of the fluorescent lamp, which also serves as a reflection plate and a waterproof measure, and the light flux emitted above the fluorescent lamp is reflected by the reflection plate toward the surface of the lower irradiation target. In this method, since the fluorescent lamp emits light in all directions around the fluorescent lamp, unevenness in illuminance is smaller than that in a method in which a plurality of spotlights are arranged. However, the illuminance difference between the upper side of the irradiation target surface closer to the fluorescent lamp and the lower side of the irradiation target surface far from the fluorescent lamp is large, and the irradiation target surface cannot be illuminated with a uniform illuminance.

In recent years, the adoption of LEDs as a light source has been advanced, and the adoption of LEDs as a light source of a device that illuminates the surface of a signboard or the like has been considered. When the LEDs are arranged in a row as the light source, there is the same illuminance unevenness as in an illumination device using a fluorescent lamp. Since the LED does not emit a luminous flux in all directions unlike a fluorescent lamp, there is almost no contribution of the reflecting plate, and in that respect, the irradiation unevenness may be larger than that of the illumination device using the combination of the fluorescent lamp and the reflecting plate.

In contrast to these methods, in the illumination system 1 shown in FIG. 1, the luminous flux from the light source 11 in which LEDs are arranged in a single row, multiple rows, zigzag, or matrix is asymmetric from the illumination device 10 with respect to the optical axis 19. Then, it is possible to output the light beam 15 including the two components 17 and 18 that are convoluted (deflected) to one side (the side of the signboard 3 and the inside). Therefore, it is possible to illuminate the signboard 3 with less unevenness in illuminance.

FIG. 2 shows a structure of the lighting device 10 by a cross section in a direction X which is a direction orthogonal to the longitudinal direction of the lighting device 10 and which is a direction perpendicular to the main surface of the signboard 3 which is an illumination target surface. In FIG. 3, the optical element 20 and the LED 11 which is a light source included in the lighting device 10 are extracted and shown. The lighting device 10 includes a housing 13 having a substantially trapezoidal cross section in the X direction and an opening 13b on the lower side, and LEDs arranged in a row in the longitudinal direction (Y direction) of the lighting device 10 on the ceiling surface 13a of the housing 13. Light source) 11 and an optical element 20 arranged in front of the light source 11 so as to face the opening 13b. The optical element 20 is a cylindrical optical element having a substantially trapezoidal cross section, and includes a transparent surface 27 that reflects the light 12 (light 12 from the light source 11) entering from the rear (upper) 20a to the front 20b. It is an optical element made of light-transmitting resin or glass. The reflection surface 27 extends in one direction (Y direction) when viewed from the front, and reflects the light 12 in a direction away from the optical axis 19 of the light in a region until the light 12 enters the optical element. Reflection surface (inner reflection surface) 25 and a second reflection surface (outer reflection surface) that extends in one direction (Y direction) when viewed from the front and reflects the light 12 in a direction intersecting the optical axis 19. Reflective surface) 26. Furthermore, the first reflecting surface 25 includes a portion along a parabola or a portion 25a along a hyperbola in a cross section (cross section in the X direction) perpendicular to the one direction, and the second reflecting surface 26 is in the X direction. Can include a portion 26a along the ellipse in the cross section.

The optical element 20 has a recess 28 at a position facing the light source 11. The recess 28 is provided behind the optical element 20, and the light 12 from the light source 11 is applied to the inner surface of the recess 28 so that the light 12 is efficiently introduced into the optical element 20 through the recess 28. It The first reflection surface 25 located inside the optical element 20 and the second reflection surface 26 located outside may be a total reflection surface, and are coded with a material having a high reflectance (for example, a metal such as aluminum). The surface may be a curved surface. Of the light 12 that enters from the rear 20a, the light (light flux) that directly reaches the front surface 29 that is the emission side via the inner bottom surface 28a of the recess 28, mainly from the central portion 21 of the front surface 29 that is the emission side, It is output as a light beam 16 that diffuses along the optical axis 19.

The reflection surface 25 on the inner side (signboard side) of the optical axis 19 is a reflection surface concave with respect to the front 20b, and reflects the light 12 reaching the reflection surface 25 from the light source 11 arranged on the rear 20a on the optical axis 19. It is provided so as not to be parallel to the optical axis 19 but to be away from the optical axis 19, that is, forward 20b so as to reflect inward of the optical axis 19 (toward the signboard). In particular, the portion 25a of the first reflecting surface 25 that is recessed along the parabola or the hyperbola allows the light 12 that has arrived from the light source 11 disposed behind the optical axis 19 to be forward 20b from the optical axis 19 as a whole. Is also suitable for reflecting inward. Therefore, of the light 12 output from the light source 11, the light that reaches the inner reflecting surface 25 via the inner surface 28 b of the recess 28 is the portion of the first reflecting surface 25 that is recessed along the parabola or hyperbola. The light is reflected by 25 a and is output as a component (light flux, first component) 17 in a direction away from the inner portion 22 of the front surface 29, which is the emission side, with respect to the optical axis 19. In this example, the first reflecting surface 25 is provided with a portion 25a along a hyperbola.

The second reflecting surface 26 located on the outer side of the optical axis 19 (the side on which the sign is observed, the side on which a person stands) is a concave reflecting surface with respect to the front 20b, and is provided on the rear 20a on the optical axis 19. The light 12 reaching the reflection surface 26 from the arranged light source 11 is not in the direction parallel to the optical axis 19 but in the front 20b inside the optical axis 19 (signboard side) and in the direction intersecting the optical axis 19. It is provided to reflect. In particular, the concave portion 26a along the ellipse reflects the light 12 arriving from the light source 11 arranged at the rear 20a of the optical axis 19 to the front 20b at a large angle in the direction intersecting the optical axis 19. Suitable for Therefore, of the light 12 output from the light source 11, the light reaching the outer reflecting surface 26 via the inner side surface 28c of the recess 28 is forwarded by the portion 26a of the second reflecting surface 26 along the ellipse 20b. And is output as a component (light flux, second component) 18 from the outside portion 23 of the front surface 29, which is the emission side, in a direction intersecting the optical axis 19, that is, from the outside of the optical axis 19 to the inside.

Thus, the optical element 20 includes the asymmetrical reflecting surfaces 25 and 26 with respect to the optical axis 19, which reflects the light 12 entering from the rear 20a in a deviated direction, not in parallel with the optical axis 19. For this reason, the light beam 15 emitted from the light source 11 after passing through the optical element 20 does not pass through the reflecting surfaces 25 and 26, but the light beam 15 from the substantially center 21 of the emitting surface 29 to the optical axis 19 as described above. A component (center component) 16 emitted along with, and a first component 17 separated from the inner side (signboard side) 22 of the emission surface 29 to the signboard 3 side with respect to the optical axis 19 by the first reflecting surface 25. , And the second component 18 that crosses the optical axis 19 toward the signboard 3 side from the outside 23 (on the side opposite to the signboard with respect to the optical axis 19) of the emission surface 29 by the second reflecting surface 26.

Further, by providing a parabolic or hyperbolic portion 25a on the first reflecting surface 25, it is possible to obtain an appropriate light distribution without making the angles of the light rays included in the reflected component 16 small while reducing the reflection angle. ing. By providing the elliptical portion 26a on the second reflecting surface 26, an appropriate light distribution can be obtained without increasing the angle of the light rays included in the reflected component 17 while increasing the reflection angle. ..

Therefore, since more components of the light 12 output from the light source 11 can be emitted toward one side with respect to the optical axis 19 by passing through the optical element 20, one side with respect to the optical axis 19 can be irradiated. The placed signboard 3 can be efficiently illuminated. Further, in the optical element 20, due to the design of the reflecting surfaces 25 and 26, the angle with respect to the central axis 19 of the first component 17 output from the inner side 22 of the emitting surface 29 and the outer side 23 of the emitting surface 29 are output. The angle of the second component 18 with respect to the optical axis 19 can be controlled independently. In the optical element 20 of this example, the first component 17 is radiated toward the upper half 3a of the signboard 3 close to the lighting device 10 to secure the illuminance above the signboard 3. On the other hand, the second component 18 is irradiated toward the lower half portion 3b of the signboard 3 which is distant from the lighting device 10 to secure the illuminance of the lower part of the signboard 3.

The signboard 3 is also illuminated by the central component 16 emitted from the center 21 of the illuminating device 10, but the illuminance of the portion where the central component 16 is difficult to reach angularly at the upper part of the signboard 3 and the illuminance decreases is the first component 17. You can help with. Further, the second component 18 can assist the lower illuminance far from the lighting device 10 and the illuminance is insufficient. Therefore, it is possible to illuminate the signboard 3 from the top to the bottom with a more uniform illuminance, and it is possible to provide the illumination device 10 with less illuminance unevenness.

The target position of the signboard 3 can be changed by the first reflecting surface 25 and the second reflecting surface 26, and the first component 17 can be aimed at the lower side of the signboard 3 by the first reflecting surface 25. It is also possible to output the second component 18 with the second reflecting surface 26 aiming at the upper side of the signboard 3.

As shown in FIG. 4, the optical element 20 may further include a prism 31 provided on a part of the front surface 29 that is the emission side. In this example, a prism 31 is provided on the inner surface 22 of the front surface 29, which is the exit side of the optical element 20, in the X direction in which the direction of the ridgeline 31b of the unit lens 31a is perpendicular to the Y direction. The outer surface 23, which is the other area of the front surface 29 on the emission side, includes a flat surface 39. The prism 31 diffuses light 12 from a plurality of light sources (LEDs) 11 intermittently arranged in the Y direction in the Y direction to suppress uneven illuminance due to the light source 11 in which point light sources are intermittently arranged in the longitudinal direction. can do.

As shown in FIG. 5A, a lenticular 32 may be used instead of the prism 31. By providing the irradiation surface 29 with the lenticulars 32 in the X direction in which the direction of the ridgeline 32b of the unit lens 32a is perpendicular to the Y direction, it is possible to suppress unevenness in the illuminance of the light source 11. Further, as shown in FIG. 5B, the unevenness of illuminance due to the light source 11 can also be suppressed by providing the embossed surface 33 on the emission surface 29.

Of the front surface 29 which is the emission side, the area (inner area) 22 located on the first reflection surface 25 side which is the inner reflection surface and the second reflection surface 26 side which is the outer reflection surface are located. When divided into a region (outer region) 23, one of the regions has a prism 31 or a lenticular 32 which is perpendicular to the ridgeline directions 31b and 32b (Y direction) of the unit lenses 31a and 32a, and the other region. Preferably has a flat surface 39. Further, of the front surface 29 which is the emitting side, there are a region (inner region) 22 located on the first reflection surface 25 side which is the inner reflection surface and a second reflection surface 26 side which is the outer reflection surface. When divided into the area (outer area) 23 located, one of the areas may have a texture 33 and the other area may have a flat surface 39.

Of the components included in the light flux 15 emitted from the lighting device 10, the component that illuminates the area of the signboard 3 that is closer to the lighting device 10 is a light source compared to the component that illuminates the area of the signboard 3 that is far from the lighting device 10. Illuminance unevenness of 11 is included in a considerable amount. Therefore, like the optical element 20 shown in FIG. 3, the optical component 20 that is designed so that the first component 17 that passes through the inner surface 22 of the front surface 29 that is the emission side illuminates the vicinity of the lighting device 10. In the element 20, it is preferable that at least one of the prism 31, the lenticular 32, and the grain 33 is provided on the inner surface 22 of the front surface 29 through which the first component 17 that illuminates the vicinity passes. The outer surface 23 is preferably a flat surface 39 in order to secure the illuminance, and a prism 31, a lenticular 32 or a grain 33 having a different degree of diffusion may be provided in order to reduce the illuminance unevenness of the light source 11. .

In the optical element 20 that is designed such that the second component 18 that passes through the outer surface 23 of the front surface 29 that is the emission side illuminates the vicinity of the lighting device 10, the second component 18 that illuminates the vicinity. It is desirable to provide a prism 31, a lenticular 32 or a grain 33 on the outer surface 23 through which the light passes, and the inner surface 22 is preferably a flat surface 39 to secure illuminance. Similarly, the inner surface 22 may be provided with a prism 31, a lenticular 32 or a grain 33 having a different degree of diffusion in order to reduce the unevenness of illuminance of the light source 11.

FIG. 6 shows a different lighting device 10. The illumination device 10 also includes a light source 11 and an optical element 40 arranged in front of the light source 11, and is used for illuminating the signboard 3. The optical element 40 has substantially the same configuration as the optical element 20 described above, and the concave portion 28 facing the light source 11 refracts the light 12 from the light source 11 toward the first reflection surface (inner reflection surface) 25. The first inner side surface 28b, the second inner side surface 28c that refracts the light 12 from the light source 11 toward the second reflective surface (outer reflective surface) 26, the first inner side surface 28b, and the second inner side surface 28b. The inner bottom surface 28a is a surface that connects the inner side surface 28c, and an inner bottom surface 28a that focuses the light 12 by forming a convex toward the rear (light source 11).

By providing the recess 28 with the inner bottom surface 28 a that collects the light 12 from the light source 11, the diffusion of the central component 16 output from the center 21 of the emission surface 29 can be suppressed. Therefore, it is possible to suppress a decrease in the illuminance of the light flux 15 emitted from the illumination device 10 in the distance, and the lower side of the signboard 3 can be illuminated brighter. Therefore, the illuminating device 10 suitable for illuminating the signboard 3 having a larger area can be provided.

In this optical element 40, the inner bottom surface 28a of the concave portion 28 is a convex surface, but it may be a surface inclined with respect to the optical axis 19. For example, by making the surface inclined inward, the emission surface It is also possible to incline the direction of the central component 16 output from the central portion 21 of 29 with respect to the optical axis 19 (toward the signboard 3).

As described above, the illumination device 10 folds (folds) the light 12 from the light source 11 arranged rearward to one side with respect to the optical axis 19 of the light source 11 with respect to the optical axis 19. Thus, the luminous flux 15 having an asymmetric and non-uniform intensity distribution (light distribution characteristic) can be output. Therefore, in the signboard illumination system 1 that includes the lighting device 10 and the signboard 3 that is arranged beside the first reflecting surface 25 on the inside where the light of the lighting device 10 is folded, and is illuminated by the lighting device 10. 3 can be illuminated more evenly with less unevenness in illuminance.

The lighting device 10 is suitable for uniformly illuminating not only the signboard 3 but also a wide wall surface, and is used as lighting equipment for paintings in museums, as lighting equipment for posters at exhibitions, and because there is little uneven lighting. It can be used for many purposes such as lighting equipment for crime prevention on outdoor walls.

DESCRIPTION OF SYMBOLS 1 Signboard illumination system, 3 Signboard 10 lighting device, 11 Light source 20 Optical element, 25 1st reflective surface, 26 2nd reflective surface, 27 reflective surface, 28 recessed part

Claims (7)

A translucent optical element including a reflecting surface that reflects light entering from the front toward the front, and a front surface that is an emitting side ,
The reflection surface is a first reflection surface that extends in one direction when viewed from the front and reflects the light in a direction away from the optical axis of the light in a region until the light enters the optical element. If, then stretched in the one direction when viewed from the front, seen including a second reflecting surface for reflecting the light in a direction intersecting the optical axis,
When the front surface is divided into a region located on the first reflection surface side and a region located on the second reflection surface side, one of the regions has a texture and the other region is flat. Element having a flat surface . A translucent optical element including a reflecting surface that reflects light entering from the front toward the front, and a front surface that is an emitting side,
The reflection surface is a first reflection surface that extends in one direction when viewed from the front and reflects the light in a direction away from the optical axis of the light in a region until the light enters the optical element. And a second reflecting surface that extends in the one direction when viewed from the front and reflects the light in a direction intersecting the optical axis,
When the front surface is divided into a region located on the side of the first reflecting surface and a region located on the side of the second reflecting surface, one of the regions has the ridge line direction of the unit lens as the one. An optical element having a prism and a lenticular perpendicular to the direction, and the other area having a flat surface. In claim 1 or 2 ,
An optical element in which, in a cross section perpendicular to the one direction and including the optical axis, the first reflecting surface includes a parabolic portion or a hyperbolic portion, and the second reflecting surface includes an elliptical portion. In any one of Claim 1 thru| or 3 ,
An optical element having a recess provided on the rear side, the interior surface of which is irradiated with light from a light source. In claim 4 ,
The inner surface of the recess is
A first inner surface that refracts light from the light source toward the first reflective surface;
A second inner surface that refracts light from the light source toward the second reflective surface;
An optical element having a surface connecting the first inner surface and the second inner surface, and an inner bottom surface that collects the light by forming a convex shape toward the rear. An optical element according to any one of claims 1 to 5 ,
A lighting device comprising: a light source disposed behind the optical element. A lighting device according to claim 6 ;
A signboard illumination system, comprising: a signboard that is arranged beside the first reflecting surface of the lighting device and that is illuminated by the lighting device.

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