JP2018049748A - Optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element capable of controlling light distribution more flexibly. Provided 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. A second reflecting surface that extends in one direction when viewed from the front and reflects light in a direction intersecting the optical axis. [Selection diagram] Figure 2

Description

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

  Patent Document 1 describes a vehicular illumination device that can appropriately irradiate a desired light distribution pattern. The vehicle illumination device of Patent Document 1 includes a lens unit that changes incident light from an LED by refraction and emits the light, and an upper side that reflects and emits incident light from the LED by an upper reflection surface formed above the lens unit. The optical member includes a reflector portion and a lower reflector portion that reflects and emits incident light from the LED with a lower reflecting surface formed below the lens portion. A refracting portion that refracts incident light from the LED downward and guides it out of the illumination optical path is provided below the incident surface of the lens portion. Furthermore, the refraction of the entrance surface and the exit surface of the lens unit causes the vertical emission angle to be changed so as to be close to parallel light, and at this time, most of the light emitted from the lens unit due to the inclination of the optical axis is the vehicle It has a configuration that is directed diagonally forward and irradiates a region below the horizontal position of the lighting device. Thereby, the desired area | region requested | required of a fog lamp etc. can be irradiated appropriately.

JP 2010-212021 A

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

  In recent years, there has been a demand for an optical element that can control light distribution more flexibly.

  One embodiment of the present invention is a light-transmitting optical element including a reflective surface that reflects light entering from behind to the front. The reflection surface of the optical element extends in one direction when viewed from the front, and is a first reflection surface that reflects light in a direction away from the optical axis of light in a region 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 crossing the optical axis.

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

The figure which shows schematic structure of an illumination 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. The perspective view which shows the optical element which contains a prism in a part of irradiation surface. It is a figure which shows another example of an irradiation surface, Fig.5 (a) has an irradiation surface containing a lenticular, FIG.5 (b) has an irradiation surface including a wrinkle. Sectional drawing which shows the structure of a different illuminating device.

  FIG. 1 shows an example of a lighting system. This illumination system 1 is a signboard illumination system used for an external lighting signboard or the like, and can illuminate a relatively large (large) signboard with little illuminance unevenness. The lighting system 1 includes a lighting device 10 disposed above the sign 3 so as to irradiate the sign 3 standing upright in FIG. 1, and a frame 6 that supports them. The frame 6 is fixed to the ground 5. The lighting device 10 includes a light source 11 and an optical element 20 disposed in front of the light source 11. FIG. 1 shows the lighting device 10 from the side (end surface) direction, and the lighting device 10 is a (long) rod-like or columnar device extending in a direction perpendicular to the paper surface of FIG. The illuminating device 10 is disposed downward so that an optical axis 19 extending forward from the light source 11 faces the direction of the ground 5 in parallel with the sign 3, and illuminates the sign 3 with downward light 15 as a whole. In the present embodiment and also in other embodiments, the direction in which the light 15 is emitted, that is, the lower side in FIGS. 1 and 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 illumination device 10 is close to the central component 16 that diffuses forward (downward) along the optical axis 19 from the center 21 of the illumination device 10 and the sign 3 of the illumination device 10. The first component 17 output from the side (inside) 22 toward the upper half 3a of the sign 3 and the lower part of the sign 3 across the optical axis 19 from the side (outside) 23 far from the sign 3 of the lighting device 10 (Lower half part) 2nd component 18 output toward 3b is included. Therefore, the sign board 3 is illuminated by the first component 17 of the light flux 15 in the upper half 3a close to the lighting device 10, and in particular, the central component 16 is illuminated from the upper half 3a to the lower half 3b. The lower half 3 b far from the illuminating device 10 and in which the central component 16 becomes weak is illuminated by the central component 16 and the second component 18. Therefore, the illumination device 10 can illuminate the entire surface of the signboard 3, that is, from the top to the bottom, with a substantially uniform illuminance.

  As signboard illumination, a system in which a plurality of spotlights are installed is known. With this method, since the center portion of the spotlight is bright and the surroundings are dark, it is very difficult to uniformly illuminate the entire surface to be irradiated, and uneven illuminance occurs. Moreover, since it is necessary to earn the illumination intensity of a dark part, it is necessary to set the wattage of an illuminating device high, and irradiation efficiency is bad.

  There is also known a system in which a fluorescent lamp and a reflector are arranged along the upper end of the signboard to illuminate the signboard as an irradiation target surface. The reflecting plate has a cap shape that serves as both a reflecting plate and a waterproof measure at the top of the fluorescent lamp, and the light beam irradiated above the fluorescent lamp is reflected toward the lower surface to be irradiated by the reflecting plate. In this method, since the light is emitted from the fluorescent lamp in all directions around the fluorescent lamp, the illuminance unevenness is less than the method in which a plurality of spotlights are arranged. However, the illuminance difference between the upper side of the irradiation target surface near 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 uniform illuminance.

  In recent years, the use of LEDs as light sources has progressed, and the use of LEDs as light sources for devices that illuminate surfaces such as signboards has been studied. When LEDs are arranged in a row as a light source, there is illuminance unevenness similar to that of an illumination device using a fluorescent lamp. Since the LED does not emit a light beam in all directions unlike a fluorescent lamp, there is almost no contribution of the reflector, and in that respect, the irradiation unevenness may be larger than that of the illumination device using a combination of the fluorescent lamp and the reflector.

  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, a staggered pattern or a matrix is asymmetrical with respect to the optical axis 19 from the illumination device 10. Thus, it can be output as a light beam 15 including two components 17 and 18 convoluted (deflected) on one side (the side of the signboard 3 and the inside). For this reason, the signboard 3 can be illuminated in a state with less illuminance unevenness.

  In FIG. 2, the structure of the illuminating device 10 is shown by a cross section in a direction X that is a direction perpendicular to the longitudinal direction of the illuminating device 10 and is perpendicular to the main surface of the signboard 3 that is the illumination target surface. In FIG. 3, the optical element 20 included in the illumination device 10 and the LED 11 as the light source 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 line 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 disposed 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 reflective surface 27 that reflects the light 12 entering from the rear (upper) 20a (light 12 from the light source 11) to the front 20b. It is an optical element made of light 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. And a second reflecting surface (outside reflecting 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. Further, the first reflecting surface 25 includes a part along a parabola or a part 25a along a hyperbola in a cross section perpendicular to one direction (cross section in the X direction), and the second reflecting surface 26 has an X direction. A section 26a along an ellipse can be included 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 irradiated on the inner surface of the recess 28, so that the light 12 is efficiently introduced into the optical element 20 through the recess 28. The 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 by a material having high reflectivity (for example, a metal such as aluminum). It may also be a finished surface. Of the light 12 entering from the rear 20a, the light (light flux) that has directly reached the front surface 29 on the output side through the inner bottom surface 28a of the recess 28 is mainly from the central portion 21 of the front surface 29 on the output side. It is output as a luminous flux 16 that diffuses along the optical axis 19.

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

  The second reflecting surface 26 located outside the optical axis 19 (the side where the signboard is observed and the person stands) is a reflecting surface that is concave with respect to the front 20b. The light 12 arriving at the reflecting surface 26 from the arranged light source 11 is not in a direction parallel to the optical axis 19, but inside the optical axis 19 on the front 20 b (signboard side) and in a direction intersecting the optical axis 19. It is provided to reflect. In particular, the recessed portion 26a along the ellipse reflects the light 12 that has arrived from the light source 11 disposed behind the optical axis 19 at a large angle in the direction intersecting the optical axis 19 toward the front 20b. Suitable for Therefore, the light 12 that has been output from the light source 11 and has reached the outer reflecting surface 26 via the inner side surface 28c of the concave portion 28 is moved forward 20b by the portion 26a along the ellipse of the second reflecting surface 26. And is output as a component (light flux, second component) 18 that extends from the outer portion 23 of the front surface 29 on the exit side to the optical axis 19, that is, from the outer side to the inner side of the optical axis 19.

  As described above, the optical element 20 includes the reflection surfaces 25 and 26 that reflect the light 12 entering from the rear 20a in a direction that is not parallel to the optical axis 19 but is not parallel to the optical axis 19, and are non-targeted with respect to the optical axis 19. For this reason, the light beam 15 emitted from the light source 11 through the optical element 20 passes through the optical axis 19 from the substantially center 21 of the emission surface 29 without passing through the reflection surfaces 25 and 26 as described above. And a first component 17 that is separated from the inner side (signboard side) 22 of the emission surface 29 (signboard side) 22 toward the signboard 3 side with respect to the optical axis 19 by the first reflecting surface 25. The second reflecting surface 26 includes a second component 18 that crosses the optical axis 19 from the outer side (opposite side of the signboard with the optical axis 19 as a reference) 23 toward the signboard 3 side.

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

  Therefore, more components in the light 12 output from the light source 11 by passing through the optical element 20 can be irradiated toward one side with respect to the optical axis 19, so that one component with respect to the optical axis 19 is irradiated on one side. The arranged signboard 3 can be illuminated efficiently. Further, the optical element 20 is output from the angle 23 with respect to the central axis 19 of the first component 17 output from the inner side 22 of the emission surface 29 and from the outer side 23 of the emission surface 29 due to the design of the reflection surfaces 25 and 26. 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 irradiated toward the upper half 3a of the sign 3 close to the lighting device 10 to ensure the illuminance at the top of the sign 3. On the other hand, the second component 18 is irradiated toward the lower half 3 b of the signboard 3 far from the lighting device 10 to ensure the illuminance at the bottom of the signboard 3.

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

  The target position of the sign 3 can be changed between the first reflecting surface 25 and the second reflecting surface 26, and the first component 17 is aimed at the lower side of the sign 3 with 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 sign 3.

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

  As shown in FIG. 5A, a lenticular 32 may be used instead of the prism 31. By providing the lenticular 32 in the X direction in which the direction of the ridge line 32b of the unit lens 32a is perpendicular to the Y direction on the irradiation surface 29, the illuminance unevenness of the light source 11 can be suppressed. In addition, as shown in FIG. 5B, uneven illumination due to the light source 11 can also be suppressed by providing the texture 33 on the emission surface 29.

  Of the front surface 29 on the output side, it is located on the side of the first reflecting surface 25 that is the inner reflecting surface (inner region) 22 and on the second reflecting surface 26 that is the outer reflecting surface. When divided into the region (outer region) 23, one of the regions has the prism 31 or the lenticular 32 perpendicular to the ridge line directions 31b and 32b (Y direction) of the unit lenses 31a and 32a, and the other region. Preferably has a flat surface 39. Further, in the front surface 29 on the emission side, the region (inner region) 22 located on the first reflecting surface 25 side which is the inner reflecting surface and the second reflecting surface 26 side which is the outer reflecting surface are provided. When divided into the region (outer region) 23, any one of the regions may have a texture 33 and the other region may have a flat surface 39.

  Of the components included in the luminous flux 15 emitted from the illumination device 10, the component that illuminates the area of the signboard 3 close to the illumination apparatus 10 is lighter than the component that illuminates the area of the signboard 3 far from the illumination apparatus 10. 11 illuminance unevenness is included. Therefore, like the optical element 20 shown in FIG. 3, the first component 17 that passes through the inner surface 22 among the front surface 29 on the emission side is designed to illuminate the vicinity of the illumination device 10. In the element 20, it is desirable to provide at least one of the prism 31, the lenticular 32, and the texture 33 on the inner surface 22 through which the first component 17 that illuminates the vicinity of the front surface 29. The outer surface 23 is preferably a flat surface 39 in order to ensure illuminance, and a prism 31, lenticular 32 or grain 33 having a different diffusion degree may be provided to reduce illuminance unevenness of the light source 11. .

  In the optical element 20 designed so that the second component 18 passing through the outer surface 23 of the front surface 29 on the emission side illuminates the vicinity of the illumination device 10, the second component 18 that illuminates the vicinity. It is desirable to provide the prism 31, the lenticular 32, or the texture 33 on the outer surface 23 through which the light passes, and the inner surface 22 is preferably a flat surface 39 in order to ensure 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 illuminance unevenness of the light source 11.

  FIG. 6 shows a different lighting device 10. The lighting device 10 also includes a light source 11 and an optical element 40 disposed in front of the light source 11 and is used for lighting 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 reflecting surface (inner reflecting surface) 25. A first inner side surface 28b; a second inner side surface 28c that refracts the light 12 from the light source 11 toward a second reflecting surface (outer reflecting surface) 26; a first inner side surface 28b and a second inner surface 28b; It is a surface connecting the inner surface 28c, and includes an inner bottom surface 28a that condenses the light 12 by projecting toward the rear (light source 11).

  By providing the inner bottom surface 28 a that collects the light 12 from the light source 11 in the recess 28, diffusion of the central component 16 output from the center 21 of the emission surface 29 can be suppressed. For this reason, it becomes possible to suppress the fall of the illumination intensity in the distance of the light beam 15 radiate | emitted from the illuminating device 10, and the lower side of the signboard 3 can be illuminated more brightly. Therefore, the illuminating device 10 suitable for illumination of the signboard 3 with 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, a surface inclined toward the inner side, thereby forming an exit surface. It is also possible to incline the direction of the central component 16 output from the central portion 21 of 29 toward the inside (the signboard 3 side) with respect to the optical axis 19.

  As described above, the illumination device 10 folds (folds) the light 12 from the light source 11 disposed behind to the optical axis 19 of the light source 11 on one side with respect to the optical axis 19. And a light beam 15 having an asymmetric and non-uniform intensity distribution (light distribution characteristic). Therefore, in the signboard illumination system 1 having the illumination device 10 and the signboard 3 that is disposed on the side of the inner first reflection surface 25 where the light of the illumination device 10 is folded and is illuminated by the illumination device 10, the signboard 3 can be illuminated more evenly and with less illuminance unevenness.

  The lighting device 10 is suitable not only for the signboard 3 but also for lighting a wide wall evenly, as lighting equipment for paintings in art museums, as lighting equipment for posters in exhibitions, etc. It can be used for many purposes such as lighting equipment for crime prevention on the outdoor wall surface.

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

Claims (9)

A translucent optical element including a reflective surface that reflects light entering from behind to the front,
The reflective surface 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 reflective surface that extends in the one direction when viewed from the front and reflects the light in a direction intersecting the optical axis. In claim 1,
In the cross section perpendicular to the one direction and including the optical axis, the first reflective surface includes a parabolic portion or a hyperbolic portion, and the second reflective surface includes an elliptical portion. In claim 1 or 2,
An optical element having a recess provided at the rear, wherein the inner surface is irradiated with light from a light source. In claim 3,
The inner surface of the recess is
A first inner surface that refracts light from the light source toward the first reflecting surface;
A second inner surface that refracts light from the light source toward the second reflecting surface;
An optical element having an inner bottom surface that connects the first inner surface and the second inner surface and condenses the light by projecting backward. In any of claims 1 to 4,
An optical element having at least one of a prism, a lenticular, and a grain on the front surface on the output side. In any of claims 1 to 4,
When the front surface on the emission side is divided into a region located on the first reflecting surface side and a region located on the second reflecting surface side, one of the regions has a texture, and the other An optical element having a flat surface. In any of claims 1 to 4,
When the front surface on the emission side is divided into a region located on the first reflecting surface side and a region located on the second reflecting surface side, either one of the regions has a ridge line direction of the unit lens. An optical element having a prism and a lenticular perpendicular to the one direction, and the other region having a flat surface. An optical element according to any one of claims 1 to 7,
And a light source disposed behind the optical element. A lighting device according to claim 8;
A signboard illumination system comprising: a signboard disposed on a side of the first reflecting surface of the illumination device and illuminated by the illumination device.

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