JP4697726B2 - Lighting device - Google Patents

Description

  The present invention relates to an illumination device having various illumination effects by a diffraction phenomenon.

  A wide variety of light sources such as fluorescent tubes, incandescent bulbs, and light emitting diodes (hereinafter referred to as LEDs) have been developed and put on the market. These light sources are used in various devices such as lighting devices for presentations, signal lights, and backlights that are adapted to the atmosphere of the place from ordinary lighting.

  For example, a signal lamp using LEDs is usually arranged with a large number of LEDs arranged closely (see Patent Document 1). In addition, a large number of production LEDs attached to a Christmas tree or the like are necessary, and there is one LED for one light spot. However, using a large number of LEDs is uneconomical in various ways. In production lighting, there are cases where the production effect is limited by simply using LEDs.

JP 2003-036497 A (see FIG. 1)

  An object of this invention is to provide the illuminating device which has various illumination effects, even if there are few light sources, such as LED.

  The gist of the illuminating device of the present invention is to include a light source that emits light and a light-transmitting sheet that is disposed on an optical path of the light emitted from the light source and provided with a dielectric antenna serving as a diffraction grating. The light emitted from the light source is dispersed by the dielectric antenna of the light transmissive sheet, and a high-luminance light spot can be projected.

  The illumination device may be provided with a mechanism that swings the light transmissive sheet by rotation, vibration, or both.

  A diffusion sheet may be disposed on the light transmissive sheet.

  You may have a structure provided with the recessed part into which the said light source enters.

  The light transmissive sheet may have a conical shape.

  The angle of the apex of the cone may be 90 ° ± 30 °.

  The distance between the dielectric antennas is 0.01 μm to 10 cm.

  In the present invention, light can be dispersed in a lattice shape by a dielectric antenna that functions as a diffraction grating. High-intensity light can be dispersed by the dielectric antenna. The dispersed light does not diffuse and the illuminance is not inversely proportional to the square of the distance. Various lighting devices can be constructed by making good use of this dispersion of light.

  An embodiment of a lighting device of the present invention will be described with reference to the drawings. First, the basic configuration of the present invention will be described.

  As shown in FIG. 1, the illumination device 10 includes a light source 12 that emits light 14 and a light transmissive sheet 16 provided with a dielectric antenna. The above configuration is the basic configuration of the illumination device 10 of the present invention.

  The light source 12 in FIG. 1 uses a laser diode. The wavelength of the laser light is about 660 nm, for example, and the output is about 1 mW or less. In various embodiments to be described later, the light source 12 is not limited to a laser diode, and any light such as an LED can be used.

  The light transmissive sheet 16 in FIG. 2 is disposed on the optical path of the light 14 emitted from the light source 12. The light transmissive sheet 16 has a dielectric antenna 22 disposed on a transparent sheet 20. The dielectric antenna 22 formed on the light transmissive sheet 16 serves as a diffraction grating. The dielectric antenna 22 may be disposed on either side of the transparent sheet 20. The dielectric antenna 22 diffracts, transmits, and scatters the light 14. In the illumination device 10 of FIG. 1, the laser beam 14 and the light transmissive sheet 16 are perpendicular to each other.

  The dielectric antenna 22 can cope with broadband light. The dielectric antenna 22 has a cylindrical shape. Besides a cylindrical shape, a prism, a cone, a pyramid, a truncated cone, a truncated pyramid, and the like may be used. The dielectric antennas 22 are arranged in a grid pattern, but may not be arranged in a grid pattern as long as they function as a diffraction grating. The distance between the side surfaces of the dielectric antennas 22 is about 0.01 μm to 10 cm, preferably about 0.3 to 50 μm. The number of light spots L in the lattice pattern shown in FIG. 3 varies depending on the distance between the dielectric antennas 22. For example, if it is about 1 μm, the number of grid-like light spots L including the center is 7 as the brightest point closest to the center, and if it is about 4 μm, the light spot L including the center as the brightest point closest to the center is Nine points. The height of the dielectric antenna 22 is about 0.01 μm to 10 cm, preferably about 0.2 to 10 μm.

  FIG. 3 shows a pattern of light spots L projected on the wall 18 and the like when the laser light 14 is passed through the light transmissive sheet 16. As shown in FIG. 3, the light spots L are projected in a grid pattern. In FIG. 3, the central light spot L <b> 1 that is hatched is connected to the light source 12 through a light transmissive sheet 16 in a straight line. In the present specification, the symbol L generally indicates the symbols L1, L2, L3, L4, and L5.

  The numbers shown together with the symbol L indicate the order of light brightness. Although the brightness of the light spots L from L1 to L3 was sufficient by experiment, L4 and L5 were not able to obtain sufficient brightness with the brightness of commercially available LEDs. Therefore, there are nine light spots L at which sufficient brightness is obtained. Hereinafter, these nine light spots L will be examined.

  Table 1 shows the measurement results of the illuminance at each light spot L. d1 is the distance between the light transmissive sheet 16 and the wall 18 shown in FIG. d2 is the distance between the light source 12 and the light transmissive sheet 16 shown in FIG. The illuminance of the room at the time of measurement was 6 lux.

  Although depending on the transmittance of the light transmissive sheet 16, when the light 14 is passed through the light transmissive sheet 16, the illuminance at the light spot L <b> 1 is about 45 to 48% of the illuminance when the light transmissive sheet 16 is not passed. . By passing the light 14 through the light transmissive sheet 16, the light 14 is dispersed in a lattice shape as shown in FIG.

  The measurement of the illuminance at the light spots L2 and L3 in the absence of the light transmissive sheet 16 is due to the illuminance of the room. Therefore, Table 2 shows the illuminance when the influence of the illuminance of the room is removed, that is, when darkness is assumed. Table 3 shows the illuminance in the dark when the illuminance of the laser light 14 when the light transmissive sheet 16 is not provided is L0.

  Table 4 shows the relationship between the lattice pattern of the light spot L and the spread of the light 14 shown in FIGS. Θ is the two-dimensional angle of the light 14 from the light transmissive sheet 16 to the wall 18, and Ω is the solid angle of the light 14. d3 and r are distances between the light spots as shown in FIG. Table 5 shows the relationship between the irradiation distance and the lattice pattern. Further, when a general formula is obtained based on Table 5, it is as shown in Table 6.

  In summary, the light 14 can be dispersed in a lattice pattern by the light transmissive sheet 16 having the dielectric antenna 22. Due to the dispersion, the illuminance of each light 14 is reduced as compared with the light when not dispersed, but each dispersed light 14 does not diffuse and each light 14 has high luminance. That is, the illuminance of the light 14 does not decrease in inverse proportion to the square of the distance. In order to generate a plurality of high-intensity light spots L where the light 14 does not diffuse, a plurality of laser diodes are not required.

  As shown in FIG. 3, nine light spots L having sufficient illuminance are generated from one light source 14. The illuminating device 10 only has 1/9 light sources 14 as compared with the prior art, and is advantageous in terms of cost. It has been confirmed by experiment that 2n + 1 (n is a positive integer) light spots L are generated. If the same number of light spots L as in the prior art are generated, only 1 / (2n + 1) light sources 14 need be provided.

  In FIG. 1, the laser beam 14 and the light transmissive sheet 16 are perpendicular to each other, but an arbitrary angle φ may be provided as shown in FIG. Experiments confirmed that the light spots L were arranged concentrically at φ = 10-30 ° and 150-170 ° when d1 was 10 cm and d2 was 30 cm (FIG. 6). By adjusting the angle φ between the light transmissive sheet 16 and the laser light 14, the light spots L can be arranged in a lattice shape or concentric circles, and the light spots L are arranged in a curved shape depending on the angle φ. By providing the illumination device 10 with means for changing the angle of the light transmissive sheet 16, the arrangement of the light spots L can be changed. Further, a means for rotating or shaking the light transmissive sheet 16 may be provided to move the light transmissive sheet 16. The light spot L changes, and the lighting effect can be increased.

  By making good use of the basic lighting device 10 described above, various lighting devices described below are possible.

  For example, a lighting device can be applied to a stop lamp of an automobile. The stop lamp 26 in FIG. 7 includes the light source 12, the light transmissive sheet 16, and a diffusion plate (diffusion sheet) 28 in close contact with the light transmissive sheet 16. The light source 12 is one to several LEDs.

  The light 14 that has passed through the light transmissive sheet 16 is dispersed in a lattice shape. Since the light 14 dispersed as described above does not diffuse, it has high brightness. The dispersed high-intensity light 14 is diffused by the diffusion plate 28. Since the high-intensity light 14 is diffused, the light has good visibility. Even if it is one LED, it becomes light with good visibility, and it becomes a stop lamp 26 with a long life, power saving, and good visibility compared with an incandescent light bulb. The stop lamp 26 can also be used for a signal lamp or the like.

  A lighting device that can illuminate ornaments such as a Christmas tree will be described. The wall 18 in FIG. 1 is replaced with a Christmas tree or the like. The illumination device preferably illuminates the ornament from any direction. The light source is a plurality of LEDs or laser diodes. It is preferable that the LED emits a plurality of colors. As described above, since a plurality of light spots can be generated from one light source, there are fewer light sources than the conventional one and the same illumination effect as the conventional one is obtained. Further, it is preferable that the LED and the like blink. The LED is a self-flashing type LED, or the LED is flashed by connecting an oscillation circuit to the LED. Note that the lighting device may illuminate not only the decorative items but also the walls, floors, ceilings, etc. of the building, and has a light effect by flashing light.

  The backlight 30 such as the liquid crystal display of FIG. 8 will be described. The light source 12 uses an LED. The backlight 30 includes a plate-like structure 34 provided with a recess 32 for arranging the light source 12. There are a plurality of light sources 12 and recesses 32. The side surface of the recess 32 has an inclination of 45 degrees with respect to the upper surface of the structure 34. The light transmissive sheet 16 and the diffusion sheet 28 are disposed on the upper surface of the structure 34 so as to overlap each other.

  By arranging the light source 12 in the recess 32, the light concentrates on the opening of the recess 32, resulting in high brightness. That is, light is guided by an optical fiber or the like. High-luminance light is generated at a plurality of points, and this light is dispersed and diffused by the light-transmitting sheet 16 and the diffusion sheet 28, so that the backlight 30 has a higher luminance than the conventional backlight. In addition, the number of LEDs can be significantly reduced as compared with a backlight using existing LEDs.

  FIG. 9A shows a case where the lighting device is used as an ornament such as a Christmas tree 36. A laser diode or LED is used as the light source. Laser diodes or the like may be arranged in a plurality of colors, and each laser diode or the like may blink. The light transmissive sheet 16 is conical. The plurality of light transmissive sheets 16 are stacked with a gap therebetween. A rod-shaped member 38 is disposed at the conical apex, and the light transmissive sheet 16 is fixed to the member 38. A fixed base 40 is provided at the lower end of the rod-shaped member 38. A laser diode or the like is disposed on the fixed base 40 so that light is emitted toward the light transmissive sheet 16.

  A light source may be provided for each light-transmitting sheet so as to effectively produce light. FIG. 9B shows the arrangement of light sources when three light transmissive sheets 16 are used. In FIG. 9B, x indicates the position where the rod-shaped member 38 is attached, ● indicates the position of the light source of the lower light transmissive sheet 16, ▲ indicates the position of the light source of the middle light transmissive sheet 16, and □ indicates the upper position. This is the position of the light source of the light transmissive sheet 16. Depending on the positional relationship between the light source and the light transmissive sheet 16, the light path may be inclined with respect to the fixed base 40, and light may strike the light transmissive sheet 16 perpendicularly. Depending on the angle between the light-transmitting sheet 16 and the optical path, lattice-shaped or concentric light spots are generated. A light-transmitting material is used as the rod-shaped member 38, and a bright pillar can be formed by applying a part of the light source to the rod-shaped lower portion.

  Light is dispersed in a lattice pattern by the light transmissive sheet 16. Since there are a plurality of conical light-transmitting sheets 16, the light can be seen three-dimensionally and the atmosphere on the spot can be produced. A plurality of light spots are generated from one light source, and it can be seen as if many light sources are used. In addition, the cone shape mentioned above has the bottom face opened and the inside is also space. Although the light transmissive sheet 16 has a conical shape, it may have many shapes.

  When white light is passed through the light-transmitting sheet 16, the light irradiated on the wall or the like becomes a long and thin light spot L with a tail as shown in FIG. The color of the light spot L changes like a prism from the center point O side of all the light spots L toward the opposite side. The reason will be described. As shown in FIG. 11A, when white light is emitted from the light source 12, it passes through the light-transmitting sheet 16 and light 14 is irradiated onto a wall or the like. FIG. 11B is an enlarged view of a portion indicated by a circle in the light transmissive sheet 16 of FIG. The angles and distances are as shown in the figure. From FIG. 11B, the following equation is obtained.

  In the equation, m is a positive integer and λ is the wavelength of the light 14. From the above equation, it can be seen that the direction of the diffracted light 14 varies depending on the wavelength. From FIG. 11A, the optical path difference = xsin θ, and the following equation holds.

  That is, it can be seen that the position of the irradiated light 14 varies depending on the wavelength. Therefore, as shown in FIG. 10, when white light passes through the light-transmitting sheet 16, the light color changes from the center point O side toward the outside. As for the change of light, blue light is irradiated on the center O side in FIG.

  9A, if the optical path has an inclination of 90 ° with respect to the fixed base 40, the bottom surface passes through the apex of the conical light-transmitting sheet 16 as shown in FIG. 12A. The angle θ between the line orthogonal to the light transmissive sheet 16 is preferably about 45 ° ± 15 °. That is, the light has an inclination of about 45 ° ± 15 ° with respect to the light transmissive sheet 16. As shown in FIG. 12B, the angle θ is preferably about 45 ° ± 15 ° even if the apex of the cone is rounded. This is because the amount of light transmitted through the light-transmitting sheet differs depending on the angle of light, and light is transmitted well if the angle θ is described above.

  Moreover, as shown in FIG. 13, you may attach the bead 42 to the light transmissive sheet | seat 16 of Fig.9 (a). The beads 42 allow the light to be collected and passed by the beads 42 and facilitate the light to travel upward.

  The light transmissive sheet 16 can also be used as a dichroic mirror. As shown in FIG. 14, the two light transmissive sheets 16 are arranged in a straight line. The light 14 to be used is white light in which RGB colors are mixed. The angle between the light transmissive sheet 16 and the light 14 is set to 45 °. When the light 14 is transmitted through the first light transmissive sheet 16, it proceeds in a different direction by a certain color and can be taken out. Further, when the light 14 is transmitted through the second light transmissive sheet 16, the light travels in a different direction by a certain color. Only the light of the remaining color goes straight. This is because the light-transmitting sheet 16 has wavelength selectivity by changing the distance between the dielectric antennas provided on the first and second light-transmitting sheets 16 and changes the diffraction of the light 14. is there. The light 14 is diffused as shown in FIGS. 3 and 6 by passing through the light transmissive sheet 16 as described above.

  As shown in FIG. 15, the light source 12 may be arranged in a cylinder 44 provided with a plurality of slits, and the conical light-transmitting sheet 16 may be provided so as to cover the cylinder 44. The light emitted from the light source 12 passes through the slit in a linear shape, and the light is diffracted by the light transmissive sheet 16. The light transmissive sheet 16 may be suspended and swung. The diffracted light will shake.

  As shown in FIG. 16, a dielectric antenna may be provided on the surface of the disk 48. The disk 48 in FIG. 16 is the bottom of a wine glass 46 or the like, and the light source 12 is arranged in the wine glass 46 and can be used as an interior. The arrangement of the dielectric antennas on the disk 48 is, for example, concentric. Adjacent dielectric antennas are arranged at equal intervals.

  As shown in FIG. 17, two discs 48 may be rotated by overlapping a part of the two discs 48 with a gap (shaded portion in FIG. 17). The rotation direction is such that the disks 48 rotate in the same direction at the overlapped portion in FIG. The light is allowed to pass through the overlapped part. Since the disk 48 rotates, the positional relationship between the light and the dielectric antenna changes with time, and the diffraction direction changes. Therefore, when the light passing through the disk 48 is irradiated on a wall (including a signboard) or the like, various movements are made depending on the rotational speed of the disk 48. Depending on the rotational speed of the disk 48, the light travels in one direction, and when the speed changes, the light travels in the opposite direction, and the light stops depending on the speed. The two disks 48 may be oval. A configuration in which the rotation speed is changed with time may be used. Note that the configuration may be such that one disk 48 is rotated.

  A dielectric antenna may be provided on the lens of the glasses. When you look at a streetlight from inside a car moving in the passenger seat of a car, the rainbow-colored light moves and you look through the kaleidoscope.

  A lighting device for production that projects rainbow-colored light such as an aurora will be described. In this configuration, the light from the light source irradiates the wall or ceiling through the light transmissive sheet. As the light source, a fluorescent tube or LED is used. A mechanism for swinging the light-transmitting sheet so as to hit a wave slowly is provided. Since light is diffracted when it passes through the dielectric antenna, the light projected on the wall or the like becomes iridescent, and the iridescent light shakes and becomes aurora. Further, an oscillation circuit may be connected to a fluorescent tube or the like so that the light blinks. The appearance and disappearance of aurora can be expressed.

  As shown in FIG. 18, a gap 52 is provided between the wall 50 and the ceiling, and the light transmissive sheet 16 is provided in the vicinity of the gap 52. The light source 12 is arranged on the side where the light transmissive sheet 16 is provided, and a person stands on the opposite side. Darken the room where the person is. By making the light 14 emitted from the light source 12 white light, the light 14 that has passed through the light-transmitting sheet 16 and the gap appears to be iridescent. In addition, a mechanism for moving the light transmissive sheet 16 by vibration or the like is provided. It looks like an aurora by shaking the light transmissive sheet 16. An oscillation circuit may be connected to a fluorescent tube or the like so that the light blinks. The appearance and disappearance of aurora can be expressed.

  18 may be modified as shown in FIG. A partition 54 having an arbitrary shape is provided in the gap between the wall 50 and the ceiling. The light transmissive sheet 16 that was in the room with the light source 12 is removed. Keep the room of the person dark. A part of the light 14 passes through the gap between the partitions 54 into the room where there is a person like a tree leaking day. When a person views light using the light transmissive sheet 16 or glasses using the light transmissive sheet 16, the light 14 looks like a rainbow. In addition, a mechanism for swinging the partition 54 back and forth and right and left is provided. As the screen 54 swings, the light looks like an aurora. An oscillation circuit may be connected to a fluorescent tube or the like so that the light blinks. The appearance and disappearance of aurora can be expressed.

  The light transmissive sheet 16 described above may be a plate-like one in addition to the sheet-like one. Further, the above-described diffusion sheet may also be a plate-like one. Further, the shape may be changed from a flat shape such as a quadrangle or a circle to a three-dimensional shape from a flat shape. Further, the light source 12 may be moved and the position of the light source 12 may be moved.

  In addition, the present invention can be carried out in a mode in which various improvements, modifications, and changes are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

It is a figure which shows the basic composition of the illuminating device of this invention. It is a figure which shows the cross section of a light transmissive sheet | seat. It is a figure which shows the light spot projected on the lattice pattern. It is a schematic diagram of a lattice pattern, (a) is a lattice pattern of light spots, (b) is a diagram showing the angle from the light transmissive sheet to the wall, (c) is from the light transmissive sheet to the wall It is a figure which shows these solid angles. It is a figure at the time of inclining a light transmissive sheet | seat with respect to the optical path. It is a figure of the light spot projected on the wall in the case of FIG. It is a figure of the illuminating device applied to the stop lamp etc. It is a figure of the illuminating device applied to the backlight. It is a figure of the illuminating device applied to the Christmas tree, (a) is a side view, (b) is a figure which shows the position of the light source of a fixed base. It is a figure which shows the mode of the light irradiated to the wall etc. in the case of FIG. It is a figure when white light passes the light transmissive sheet, (a) is a figure in which light is diffracted by light and floating eat, (b) is a diagram of the light transmissive sheet shown in (a). ○ This is an enlarged view. It is a figure which shows the relationship between light and a light transmissive sheet | seat, (a) is a cone-shaped light transmissive sheet | seat, (b) is a figure at the time of rounding the vertex of (a). It is a figure at the time of attaching a bead to a light transmissive sheet | seat. It is a figure at the time of using a light transmissive sheet as a dichroic mirror. It is a figure of the illuminating device which has arrange | positioned the cylinder which provided many slits. It is the figure which provided the dielectric antenna in the disk. It is a figure at the time of overlapping two disks. It is a figure in the case of producing aurora etc. using a light-transmitting sheet. It is a figure at the time of providing a partition between a wall and a ceiling, (a) is a side view, (b) is a front view which shows an example of a partition.

Explanation of symbols

10: Illumination device 12: Light source 14: Light 16: Light transmissive sheet (light transmissive member)
18: Wall 20: Transparent sheet 22: Dielectric antenna 26: Stop lamp 28: Diffusion plate (diffusion sheet, diffusion member)
30: Backlight 32: Recess 34: Structure 36: Christmas tree 38: Bar-shaped member 40: Fixing base

Claims (2)

One light source that emits light;
A plurality of light beams arranged on the optical path of the light emitted from the light source, provided with a plurality of convex dielectric antennas serving as diffraction gratings on a transparent sheet , and having a conical shape with a bottom opening and a gap provided therebetween A permeable member;
Including
The distance between the dielectric antennas is 0.01 μm to 10 cm, and a light source is provided on the lower side of the bottom surface of the light transmissive member positioned at the bottom of the plurality of light transmissive members stacked in a conical gap. The light is viewed three-dimensionally by the diffraction of light by the dielectric antenna provided on the light-transmitting member having the conical shape and the angle between the light path and the light-transmitting member, and a plurality of lines arranged in a lattice shape An illumination device capable of projecting a light spot or a plurality of light spots arranged concentrically at an irradiation position. The lighting device according to claim 1, wherein the light source blinks light.

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