JP5954663B2 - lighting equipment - Google Patents

Description

  The present invention relates to a luminaire including a light guide plate that propagates light introduced from a light emitting element and guides the light to the outside.

  The structure of the conventional lighting fixture is shown in FIG.7 and FIG.8. The luminaire 100 includes eight LED line units (hereinafter simply referred to as LED units) 102 having LEDs 101 arranged in a line and arranged in an octagonal ring shape, and an annular shape arranged so as to surround the LED unit 102. A light guide plate 103. The LED unit 102 emits light toward the inner peripheral surface of the light guide plate 103. The light guide plate 103 has a plurality of incident surfaces 104 facing the LED units 102 on the inner peripheral surface thereof. The light guide plate 103 introduces light emitted from the LED unit 102 from the incident surface 104 and radiates the light to the outside while propagating in the outer peripheral direction of the light guide plate 103.

JP 2011-222420 A

The luminance distribution of the light guide plate 103 in the lighting fixture 100 described above will be described. Here, it is assumed that the light guide plate 103 is made of acrylic and the refractive index is 1.49. In this case, as shown in FIG. 8 above, with respect to the light incident from the incident surface 104 of the light guide plate 103, assuming that the incident angle is θ ₁ and the refraction angle is θ ₂ , the following equation (1) is obtained according to Snell's law. It holds.

According to the above formula (1), when the incident angle θ ₁ is the maximum and 90 degrees, the refraction angle θ ₂ is approximately 42 degrees. Therefore, even if the light radiation intensity distribution of each LED unit 102 is a wide-angle distribution called a Lambertian distribution, the light incident from each incident surface 104 is approximately at most about the direction orthogonal to the incident surface 104. It extends only to the direction of 42 degrees. For this reason, the light distribution becomes a narrow angle, the light gathers in a narrow area, and the luminance increases. As a result, as shown in FIG. 7, the luminance difference between the overlapping region A2 ′ and the other region A3 ′ among the propagation regions A1 ′ of light incident from the adjacent incident surfaces 104 increases. . Therefore, the boundary between these regions A2 ′ and A3 ′ becomes clear, and the luminance unevenness becomes conspicuous.

  The present invention has been made to solve the above-described problem, and suppresses uneven luminance of a light guide plate in a lighting fixture including a light guide plate that propagates light introduced from a plurality of light emitting elements and derives the light to the outside. It is an object of the present invention to provide a lighting device that can be used.

  In order to achieve the above object, a lighting fixture of the present invention is arranged so as to surround a plurality of light emitting elements arranged in a polygonal ring and the plurality of light emitting elements, and introduces light from the plurality of light emitting elements. The light guide plate includes an annular light guide plate that propagates the introduced light and leads out to the outside, and the light guide plate introduces light of the plurality of light emitting elements from an inner peripheral surface of the light guide plate. The introduced light is configured to be guided to the outside while propagating in the outer peripheral direction of the light guide plate, and the inner peripheral surface of the light guide plate is provided for each side of the polygonal ring formed by the plurality of light emitting elements. There is a series of a plurality of incident surfaces that face the light emitting elements and on which light from the light emitting elements is incident, and a corner member is guided to fill the corners of the connecting portions of the incident surfaces adjacent to each other in the light guide plate. It is formed integrally with the light plate.

  The surface of the corner member is preferably formed in an R shape.

  It is preferable that the surface of the corner member is formed to diffuse light incident on the light guide plate from the surface.

  The arrangement shape of the plurality of light emitting elements is preferably a regular polygonal ring.

  According to the present invention, light from the light emitting elements arranged on each side of the polygonal ring enters the light guide plate from each incident surface on the inner peripheral surface of the light guide plate and the surfaces of the corner members on both sides thereof. Light incident from the surfaces of the corner members on both sides is refracted on those surfaces so as to travel at a larger angle to both sides with respect to the light propagation direction by the light guide plate. Therefore, the light propagation region of the light emitting element on each side of the light guide plate is expanded, and the luminance of each propagation region is lowered. As a result, a luminance difference between an overlapping region and a non-overlapping region among adjacent propagation regions is reduced, and uneven luminance can be suppressed.

Sectional drawing of the lighting fixture which concerns on one Embodiment of this invention. The top view seen from the fixture lower side of the state which removed the cover in the said lighting fixture. The top view seen from the fixture lower part of the inner peripheral part of the LED line unit in the said lighting fixture, and a light-guide plate. The top view seen from the instrument downward direction of the entrance plane connection part of the said light-guide plate. The top view seen from the fixture lower part of the entrance plane connection part of the light-guide plate in the lighting fixture which concerns on the 1st modification of the said embodiment. The top view seen from the fixture lower part of the entrance plane connection part of the light-guide plate in the lighting fixture which concerns on the 2nd modification of the said embodiment. The top view seen from the fixture downward direction of the conventional lighting fixture. The top view seen from the fixture lower part of the entrance plane connection part of the light-guide plate in the said lighting fixture.

  The lighting fixture which concerns on one Embodiment of this invention is demonstrated with reference to drawings. FIG.1 and FIG.2 shows the structure of the lighting fixture of this embodiment. The luminaire 1 is suitable for general illumination that is installed on a ceiling of a house or an office to illuminate an indoor space. The luminaire 1 includes a plurality of LEDs 2 (light emitting elements) arranged in a polygonal annular shape, and an annular light guide plate 3 disposed so as to surround the LEDs 2. The LED 2 is disposed so as to emit light toward the light guide plate 3. The light guide plate 3 has an inner peripheral surface 31 for introducing the light of the LED 2 into the light guide plate 3, so that the light introduced from the inner peripheral surface 31 is guided to the outside while propagating in the outer peripheral direction of the light guide plate 3. It is configured. The inner peripheral surface 31 of the light guide plate 3 has a series of a plurality of incident surfaces 32 opposed to the LEDs 2 for each side of the polygonal ring formed by the LEDs 2, and the incident surfaces 32 respectively oppose the incident surfaces 32. The light of the LED 2 to be incident enters.

  Moreover, the lighting fixture 1 is provided with the some board | substrate 4 with which LED2 was mounted, and the case 5 which accommodates said each component. The case 5 includes a case main body 51 and a cover 52 that is detachably attached to the case main body 51.

  The arrangement shape of the LEDs 2 is a regular polygonal ring, for example, a regular octagonal ring, and the LEDs 2 are arranged along the outline of the regular octagon. The number of LEDs 2 arranged is not limited to the number shown. The LEDs 2 are mounted on a single substrate 4 at equal intervals for each side of the regular octagonal ring formed by the LEDs 2 and constitute one LED line unit (hereinafter simply referred to as an LED unit) 20.

  Each LED 2 is composed of, for example, an SMD (Surface Mount Device) type white LED, but is not limited thereto. Each LED 2 may be a blue LED chip. In that case, the LED unit 20 is a phosphor in which the blue LED chip is directly mounted on the substrate 4 and converts blue light to yellow light on the blue LED chip. The COB (Chip on Board) type is provided.

  In addition to the incident surface 32 described above, the light guide plate 3 directly reflects the light incident from the incident surface 32 in the outer peripheral direction of the light guide plate 3 and the light reflected by the upper bottom surface 33 and the inner peripheral surface 31. A lower bottom surface 34 for emitting incoming light to the outside and an outer peripheral surface 35.

  Since the arrangement shape of the LEDs 2 is a regular octagonal ring, eight incident surfaces 32 are provided corresponding to the arrangement shape, and form a regular octagon in a state where the light guide plate 3 is viewed in plan view. The upper bottom surface 33 is on the case body 51 side, and the lower bottom surface 34 is on the cover 52 side. Although not shown, the upper bottom surface 33 is subjected to surface processing. This surface processing reflects and diffuses light incident on the light guide plate 3 from the inner peripheral surface 31 to form a surface shape from the lower bottom surface 34. This is a process for uniform emission. Examples of the surface processing include fine prism formation, dot silk printing, and laser dot formation, and are selected according to the application. The density distribution of the prisms or dots is designed so that the luminance distribution of the lower bottom surface 34 is a uniform distribution. The upper bottom surface 33 is provided with a reflection diffusion sheet 6 in order to improve light reflection efficiency and light diffusion efficiency at the upper bottom surface 33. The reflection diffusion sheet 6 is a sheet having high light reflectivity and high light diffusion property, and reflects and diffuses light that is about to go out from the upper bottom surface 33 of the light guide plate 3 so as to return to the inside of the light guide plate 3.

  The light guide plate 3 is attached to the case body 51 so as to be concentrically arranged with the regular octagonal ring formed by the LEDs 2. The outer peripheral shape of the light guide plate 3 is, for example, circular in order to make the amount of light emitted from the outer peripheral surface 35 substantially equal in each direction. The light guide plate 3 is made of transparent resin or transparent glass. As the transparent resin, acrylic, polycarbonate, cycloolefin, or the like can be used, but acrylic is desirable from the viewpoint of manufacturing cost and light propagation efficiency.

  The substrate 4 is configured by a rigid substrate, a flexible substrate, or a rigid flexible substrate. In the case of a ridged substrate, paper phenol, paper epoxy, glass composite, glass epoxy, Teflon (registered trademark), alumina, low-temperature co-fired ceramic, composite, or halogen-free is used as the material. In the case of a flexible substrate, polyimide or polyester is used as the material. A heat radiating plate for releasing heat of the LED 2 to the outside may be attached to the substrate 4.

  The case body 51 is made of resin, metal, or the like, and is installed on the ceiling or the like. The cover 52 is obtained by dispersing a light diffusing material in a transparent resin such as acrylic or polycarbonate, has a light transmitting property and a light diffusing property, and transmits and diffuses light emitted from the light guide plate 3. As the light diffusing material, for example, particles made of titanium oxide or calcium carbonate are used.

3 and 4 show the configuration of the connecting portion 32a of the adjacent incident surfaces 32 in the light guide plate 3. FIG. In the connecting portion 32a, a corner member 36 is formed integrally with the light guide plate 3 from the same material as the light guide plate 3 so as to fill the corner 32b (see FIG. 4) of the connecting portion 32a. The surface of the corner member 36 is a plane. The planes have inclinations of substantially the same inclination angle θ ₃ with respect to two planes (shown by broken lines) each including the incident surfaces 32 on both sides. Entrance surface 32 are arranged in octagonal shape, the angle of the corner 32b of the connecting portion 32a is because it is substantially 135 degrees, the inclination angle theta ₃ is approximately 22.5 degrees. The corner member 36 is disposed closer to the corner 32b than the portion of the incident surface 32 facing the LED 2.

  The light of the LED unit 20 enters the light guide plate 3 from the incident surface 32 facing the LED unit 20 and the surfaces of the corner members 36 on both sides of the incident surface 32. A method for spreading the incident light within the light guide plate 3 will be described with reference to FIG.

Out of the light from the LED unit 20, the light at the end enters the light guide plate 3 from the surface of the corner member 36. Here, it is assumed that the light incident from the surface of the corner member 36 has an incident angle of θ ₄ , a refraction angle of θ ₅ , and the light guide plate 3 is made of acrylic (refractive index: 1.49). In this case, the following formula (2) is established according to Snell's law.

Of the light incident from the surface of the corner member 36, the light incident at the maximum incident angle θ ₄ is light that travels substantially parallel to the incident surface 32. The incident angle θ _{4 of the} light is approximately 67.5 degrees when calculated based on the inclination angle θ ₃ . If the value of this incident angle θ ₄ is substituted into the above equation (2), the refraction angle θ ₅ becomes approximately 38.3 degrees. The refraction angle θ ₅ is an angle with respect to a direction orthogonal to the surface of the corner member 36, and when this angle is converted into an angle θ ₆ with respect to the direction orthogonal to the incident surface 32 based on the inclination angle θ ₃ , the angle θ ₆ is approximately 60.8 degrees. On the other hand, the maximum refraction angle theta ₂ of the light incident from the incident surface 32, as described above, is approximately 42 degrees. This angle is an angle with respect to the direction orthogonal to the incident surface 32, and is smaller than the angle θ ₆ (≈61 degrees).

  Accordingly, the light incident from the surfaces of the incident surface 32 and the corner members 36 on both sides of the incident surface 32 as a whole has a maximum angle of approximately 61 degrees with respect to the direction orthogonal to the incident surface 32, and the light propagation by the light guide plate 3. Propagates so as to spread on both sides of the direction. As a result, the light distribution becomes a wide angle as compared with the conventional case where the corner member 36 is not provided and the light spreads at a maximum angle of approximately 42 degrees.

  In the above embodiment, the light of each LED unit 20 enters the light guide plate 3 from each incident surface 32 present on the inner peripheral surface 31 of the light guide plate 3 and the surfaces of the corner members 36 on both sides thereof. The light incident from the surfaces of the corner members 36 on both sides is refracted so as to travel at a larger angle on both surfaces to both sides with respect to the light propagation direction by the light guide plate 3. Therefore, the light propagation area A1 of each LED unit 20 in the light guide plate 3 is wider than the conventional propagation area A1 ', and the luminance is lowered particularly near both ends of each propagation area A1 (see FIG. 3 again). As a result, the luminance difference between the overlapping area A2 and the non-overlapping area A3 in the adjacent propagation areas A1 is reduced. Therefore, the boundary between the regions A2 and A3 can be made inconspicuous, and the luminance unevenness of the light guide plate 3 can be suppressed.

  Moreover, since each LED unit 20 is arrange | positioned at regular polygonal ring shape, the structure of each LED unit 20, such as a dimension or the number of LED installation, can be made the same, and each LED unit 20 can be shared. Therefore, the manufacturing cost can be reduced.

Next, the lighting fixture 1 which concerns on the various modifications of the said embodiment is demonstrated with reference to drawings. The same reference numerals are given to the same constituent members as those in the above embodiment. Only differences from the above embodiment will be described.
(First modification)
FIG. 5 shows a configuration of the corner member 36 of the lighting fixture 1 according to the first modification. The surface of the corner member 36 in the lighting fixture 1 of this modification is formed in an R shape and recessed.

  By the way, in the said embodiment, since the surface of the corner member 36 is a plane, even if the incident position differs about the light which injects from the surface, if the light advancing direction is the same, the incident angle will be the same Become. Therefore, the refraction angle is the same.

  On the other hand, in the present modification, the surface of the corner member 36 is recessed in an R shape, so that the incident angle of the light incident from the surface is different even if the light traveling direction is the same if the incident position is different. Different. Therefore, the refraction angle is also different. In this way, the light incident on the surface of the corner member 36 is refracted so as to spread according to the curvature of the surface of the corner member 36, and is distributed at a wide angle. Therefore, for the light emitted from each LED unit 20 and incident from the incident surface 32 and the corner member 36 of the light guide plate 3, the light propagation area A1 can be further expanded, and the luminance is further reduced particularly near the end of the propagation area A1. Can be made.

(Second modification)
FIG. 6 shows a configuration of the corner member 36 of the lighting fixture 1 according to the second modification. The surface of the corner member 36 in the lighting fixture 1 of this modification is formed so as to diffuse light incident on the light guide plate 3 from the surface. As a method for forming such a surface, for example, there is a method in which sandblasting is performed after the light guide plate 3 is manufactured. When the light guide plate 3 is a resin molded product by a mold, there is a method of forming a fine prism on the surface of the corner member 36 by a mold during molding. In the present modification, the light incident from the surface of the corner member 36 is diffused, so that the light propagation region A1 can be further expanded, and the luminance can be further reduced particularly near the end of the propagation region A1.

  In addition, this invention is not limited to the structure of said embodiment and each modification, A various deformation | transformation is possible according to the intended purpose. For example, the LED 2 may be arranged in a polygonal ring shape and may not be a regular polygonal ring. Moreover, LED2 may be comprised by bullet-type LED. In addition, in order to further reduce the luminance unevenness of the light guide plate 3, a plate-like or sheet-like light diffusing member having translucency and light diffusibility may be provided on the lower bottom surface 34 of the light guide plate 3.

1 Lighting equipment 2 LED (light emitting element)
3 Light guide plate 31 Inner peripheral surface 32 Incident surface 32a Connection part 36 Corner member

Claims (4)

A plurality of light emitting elements arranged in a polygonal ring, and disposed so as to surround the plurality of light emitting elements, introduce light from the plurality of light emitting elements, and propagate the introduced light to the outside while propagating the light. In a lighting fixture comprising an annular light guide plate,
The light guide plate is configured to introduce light from the plurality of light emitting elements from an inner peripheral surface of the light guide plate, and to guide the introduced light to the outside while propagating in the outer peripheral direction of the light guide plate.
The inner peripheral surface of the light guide plate has a series of a plurality of incident surfaces that face the light-emitting elements for each side of a polygonal ring formed by the plurality of light-emitting elements and on which light from the light-emitting elements is incident.
A corner fixture is integrally formed with the light guide plate so as to fill a corner at a connecting portion of the incident surfaces adjacent to each other in the light guide plate.   The lighting device according to claim 1, wherein a surface of the corner member is formed in an R shape.   The lighting device according to claim 1, wherein a surface of the corner member is formed to diffuse light incident on the light guide plate from the surface.   The lighting fixture according to any one of claims 1 to 3, wherein an arrangement shape of the plurality of light emitting elements is a regular polygonal ring shape.

Images