JP2012256434A - Light reflection plate, and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a lighting device using point light sources such as LEDs to uniformly diffuse light over a wider range.SOLUTION: The light reflection plate or the like is provided with a plane-view annular bottom face part, a first annular inclined face part extended from an outer edge of the bottom face part as an ascending slope outward in a radial direction, and a second annular inclined face part extended from an inner edge of the bottom face part as an ascending slope inward in the radial direction. At the bottom face part, a plurality of point light sources are provided at intervals in a peripheral direction, and the first annular inclined face part and the second annular inclined face part are each used as a reflecting face for reflecting light of the point light sources, with an elevation angle of the first annular inclined face part of more than 0 degrees and not more than 30 degrees and that of the second annular inclined face part of 15 degrees or more and 60 degrees or less.

Description

  The present invention relates to a light reflecting plate for reflecting light emitted from a point light source, and an illumination device provided with the light reflecting plate.

In recent years, white light-emitting diodes (LEDs) have been developed, and the white LEDs are rapidly expanding their applications because they are more energy efficient and have a longer life than ordinary fluorescent and incandescent bulbs.
For example, it has been studied to use an illumination device equipped with a plurality of point light sources such as white LEDs in place of conventional fluorescent lamps.

However, in general, LEDs have a small “directivity angle” value indicating the range from the brightest point to the light intensity being halved. Difficult to irradiate over area.
For this reason, efforts have been made to increase the directivity angle of the LED, and in order to use it as a general illumination light although a directivity angle of about 120 degrees has come to be marketed. There is a need to diffuse light over a wider range.

Further, in the following Patent Document 1, etc., a light reflecting plate in which receiving concave portions having inverted polygonal frustum shapes for storing LEDs are arranged vertically and horizontally is formed by bending a flat plate member having excellent light reflectivity. It is described that a lighting device provided with a flat light diffusing member (light diffusing plate) excellent in light diffusibility so as to face the light reflecting plate is used, and the lighting device is disposed in the housing recess of the light reflecting plate. It describes that light emitted from an LED is reflected on the inner wall surface of the light reflecting plate and the reflected light is diffused by a light diffusing member.
However, such an illuminating device can expect a certain effect on the uniformity of the light irradiated in the front direction by maintaining a certain distance between the light source and the light diffusion plate, but the amount of light irradiated to the side It is difficult to expect the effect of increasing
That is, in the conventional lighting device, it is difficult to irradiate with sufficient light in directions other than the directivity angle.

International Publication WO2007 / 037035

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to uniformly diffuse light over a wider range in an illumination device using a point light source such as an LED.

  When the light diffusing member is arranged so as to face the light reflecting plate, the present inventors have a multiple reflection phenomenon in which the reflected light reflected by the light reflecting plate is reflected again to the light reflecting plate side by the light diffusing member. As a result of diligent studies, the inventors have found that light emitted from a point light source such as an LED can be diffused in a wider range by giving a predetermined shape to the light reflection plate, thereby completing the present invention. Is.

  That is, the present invention relating to the light reflecting plate includes a bottom surface portion that is annular in plan view, a first annular inclined surface portion that extends upward from the outer edge of the bottom surface portion in the radial direction, and the inner edge of the bottom surface portion. And a second annular inclined surface portion extending upward inward in the radial direction, and a plurality of point light sources are arranged on the bottom surface portion at intervals in the circumferential direction, and the first annular inclined surface The surface portion and the second annular inclined surface portion are used as a reflecting surface for reflecting the light of the point light source, and the elevation angle of the first annular inclined surface portion is more than 0 degree and not more than 30 degrees, and the second The elevation angle of the annular inclined surface portion is 15 degrees or more and 60 degrees or less.

  Moreover, this invention which concerns on an illuminating device has the light-emitting device provided with the some point light source, the light reflection board, and the light-diffusion member, One surface of the said light reflection board emits the light which the point light source of the said light-emitting device emits The illumination device is configured to reflect the reflected light to the side and diffuse the reflected light by the light diffusing member disposed in front of the light reflecting direction of the light reflecting plate. An annular bottom surface portion, a first annular inclined surface portion extending in an upward gradient from the outer edge of the bottom surface portion in the radial direction, and an upward gradient inward from the inner edge of the bottom surface portion in the radial direction. And a point light source of the light emitting device is disposed on the bottom surface portion with a circumferential interval, and the first annular inclined surface portion and the second annular inclined surface portion are the point. The first annular inclined surface is used as a reflecting surface for reflecting light from a light source. Elevation is 30 degrees greater than 0 degrees and is characterized in that the elevation angle of the second inclined annular surface portion is less than 60 degrees 15 degrees.

According to the present invention, the bottom surface portion of the light reflecting plate on which the point light source is disposed is arranged in a ring shape in plan view, and the first used as a reflection surface for reflecting the light of the point light source to the inside and outside of the bottom surface portion. An annular inclined surface portion and a second annular inclined surface portion are provided, and the second annular inclined surface portion extending as an upward gradient from the inner edge of the bottom surface portion toward the radially inner side has an elevation angle of 15 degrees to 60 degrees. Therefore, the light reflected from the light diffusing member toward the light reflecting plate can be reflected radially outward.
In addition, since the first annular inclined surface portion extending as an upward gradient from the outer edge of the bottom surface portion toward the outside in the radial direction is formed with a small elevation angle of more than 0 degrees and 30 degrees or less, the second annular shape It is possible to suppress the possibility that the light reflected by the inclined surface portion is reflected again by the first annular inclined surface portion and the irradiation of light radially outward is obstructed.
Therefore, the light reflecting plate of the present invention can reflect light emitted from a point light source such as an LED at a low angle radially outward, and can irradiate light over a wide range by using the light reflecting plate. Can be provided.

The schematic plan view which shows the whole shape of a light reflection board. The schematic plan view of the division piece which comprises a light reflection board. FIG. 3 is a schematic sectional view taken along line YY in FIG. 2. (A) The schematic plan view which shows the sample used for evaluation of a light reflection board, (b) ZZ schematic sectional drawing. The (a) top view, (b) front view, and (c) side view which simulated the illuminating device. The schematic sectional drawing which shows the evaluation samples, such as Example 3. FIG.

Embodiments of the present invention will be described below.
FIG. 1 is a schematic plan view showing a light reflecting plate of the present embodiment, and the light reflecting plate 100 is formed so that the shape in plan view is a donut shape (a hollow disc shape).
FIG. 2 is a plan view of a divided piece obtained by dividing the light reflecting plate 100 into four in the circumferential direction, and the light reflecting plate 100 of this embodiment is formed by combining the divided pieces 1.
More specifically, the divided piece 1 has a shape obtained by cutting the light reflecting plate along two straight lines passing through the center of the donut-shaped light reflecting plate 100 and orthogonal to each other. The shape in is a fan shape.
That is, the divided piece 1 has the same arc as that of a circle having a radius of curvature that is the same as the radius of the circle that defines the outer peripheral edge of the light reflecting plate 100, and the same width in the radial direction of the light diffusion plate. The two lines drawn with two straight lines extending in length from both ends of the arc toward the center of the light reflecting plate and the same radius of curvature as the radius of the circle defining the inner periphery of the light reflecting plate It has a fan-shaped outline defined by four sides with an arc connecting the straight lines.

3 is a cross-sectional view taken along line YY shown in FIG. 2, and as shown in FIG. 3, the divided piece 1 is formed of a sheet body having a constant thickness. .
More specifically, the divided piece 1 is obtained by thermoforming a thermoplastic resin sheet, and is provided with a three-dimensional shape by the thermoforming.

The light reflecting plate 100 according to this embodiment in which the divided pieces 1 are combined is provided with a bottom surface portion 10 having an annular shape in plan view, and the four annular bottom surface portions 10 are arranged concentrically. (Hereinafter, also referred to as a first bottom surface portion, a second bottom surface portion, a third bottom surface portion, and a fourth bottom surface portion in order from the inside).
The innermost first bottom surface portion of the four bottom surface portions 10 and the second bottom surface portion provided so as to surround the first bottom surface portion from the outside are arranged at predetermined intervals in the radial direction. The distance between the outer edge of the first bottom surface portion and the inner edge of the second bottom surface portion is substantially constant over the entire circumference.
Similarly, between the second bottom surface portion and the third bottom surface portion provided so as to surround the second bottom surface portion from the outside, between the third bottom surface portion and the fourth bottom surface portion arranged on the outermost periphery side. There is also a predetermined distance between them.

The divided piece 1 is formed such that when the light reflecting plate is formed, the first bottom surface portion is substantially flush with the entire circumference, and the first bottom surface portion is inclined or uneven. It is formed so that it can be a horizontal plane without any.
The divided piece 1 is formed so that a virtual plane obtained by extending the first bottom surface portion radially outward and the second bottom surface portion are flush with each other. The three bottom surface portions and the fourth bottom surface portion are formed to be flush with each other.
That is, the light reflecting plate of this embodiment is formed so that all the bottom surface portions from the first bottom surface portion to the fourth bottom surface portion are horizontal surfaces, and all the bottom surface portions are located on the same plane. Is formed.

The light reflecting plate in the present embodiment is configured such that a plurality of point light sources are arranged on the bottom surface portion 10 with a predetermined interval in the circumferential direction. A plurality of through holes 11 are provided in the bottom surface portion 10 at predetermined intervals so as to be inserted from the back surface side of the light reflecting plate.
The light reflecting plate in the present embodiment is provided with a light reflecting surface for reflecting the light emitted from the point light source on the inside and outside of the annular bottom surface portion, and is directed radially outward from the outer edge of each bottom surface portion. The first annular inclined surface portion 20 extends as an upward slope and has an annular shape that is concentric with the bottom surface portion in plan view.
Further, the light reflecting plate in the present embodiment extends in an upward gradient from the inner edge of each bottom surface portion inward in the radial direction, and has a second shape in which the shape in plan view is concentric with the bottom surface portion. An annular inclined surface portion 30 is further provided.
These annular inclined surface portions are provided to function as the light reflecting surface, are formed to have a constant width over the entire circumference, and the inclination angle is also constant over the entire circumference.
The first annular inclined surface portion outside the fourth bottom surface portion is substantially flat, unlike the first annular inclined surface portion 20 provided outside the other bottom surface portion, and only slightly. Not tilted.

In the present embodiment, the first annular inclined surface portion and the second annular inclined surface portion of the two bottom surface portions adjacent to each other in the radial direction in the radial direction are concentric with the bottom surface portion 10 in a plan view annular shape. The connection part 40 is provided so as to function as a light reflection surface in the same manner as the first annular inclined surface part and the second annular inclined surface part.
The connecting portion 40 in the present embodiment is provided between the first bottom surface portion and the second bottom surface portion so as to be parallel to these bottom surface portions, but the second bottom surface portion and the third bottom surface portion. And between the third bottom surface portion and the fourth bottom surface portion so as to be upwardly inclined at an elevation angle smaller than that of the first annular inclined surface portion.
And the height of the connection part 40 between the 3rd bottom face part and the 4th bottom face part is higher than the connection part 40 between the 2nd bottom face part and the 3rd bottom face part.
Therefore, the light reflecting plate of the present embodiment is, for example, the starting point (from the outer edge of the second bottom surface portion) toward the radially outward side of the connection portion 40 provided between the second bottom surface portion and the third bottom surface portion. The end point (the apex of the second annular inclined surface portion extending from the inner edge of the third bottom surface portion) is slightly higher than the end of the first annular inclined surface portion, and the third bottom surface portion and the fourth end point are higher than the end point. The starting point of the connecting portion 40 with the bottom surface portion (the apex of the first annular inclined surface portion extending from the outer edge of the third bottom surface portion) is higher.
And the vertex of the 2nd cyclic | annular inclined surface part extended from the inner edge of a 4th bottom face part becomes higher than the vertex of the 1st cyclic | annular inclined surface part extended from the outer edge of this 3rd bottom face part.

The second annular inclined surface portion reflects the light emitted from the point light source disposed on the outer bottom surface portion radially outward, and when the light diffusion plate is disposed so as to face the light reflecting plate. The light diffusing plate is provided to reflect the light reflected again to the light reflecting plate side radially outward.
That is, most of the light irradiated on the front surface side of the light reflecting plate passes through the light diffusing plate and is irradiated on the front surface side, but part of the light is reflected on the back surface of the light diffusing plate and is reflected on the light reflecting plate side. In order to return, the light reflecting plate of this embodiment is configured to reflect the light radially outward using the second annular inclined surface portion.
Accordingly, when the second annular inclined surface portion has an excessively high angle with respect to the horizontal plane, the light emitted from the point light source is excellent in the effect of reflecting radially outward, while being reflected by the light diffusion plate and returned. There is a possibility that the effect of reflecting light radially outward will be insufficient.
In addition, if the second annular inclined surface portion has an excessively high angle with respect to the horizontal plane, the light is excessively reflected outward in the radial direction.
On the other hand, when the second annular inclined surface portion has an excessively low angle with respect to the horizontal plane, the effect of reflecting the light emitted from the point light source radially outward may be insufficient.
In addition, when the first annular inclined surface portion arranged outside the second annular inclined surface portion via the bottom surface is at a high angle with respect to the horizontal plane, the light reflected by the second annular inclined surface portion is again emitted. There is a risk of reflection in the central direction of the reflector.

  For this reason, in diffusing the light emitted from the light source over a wide range with the light reflecting plate, the elevation angle of the first annular inclined surface portion is more than 0 degree and not more than 30 degrees, and the second annular shape. It is important that the elevation angle of the inclined surface portion is not less than 15 degrees and not more than 60 degrees.

  Note that it is not necessary for all the first annular inclined surface portions and the second annular inclined surface portions to be formed on the light reflecting plate of the present embodiment to have a common angle. For example, the first annular inclined surface extending from the first bottom surface portion. The surface portion and the first annular inclined surface portion extending from the second bottom surface portion may have different angles.

Moreover, you may change an angle in one 1st cyclic | annular inclined surface part or a 2nd cyclic | annular inclined surface part.
For example, the first annular inclined surface portion is formed in such a manner that the elevation angle is 30 degrees at the rising portion from the outer edge of the bottom surface portion, the angle is decreased toward the top portion, and the surface is substantially horizontal near the boundary with the connection portion. Also good.
Further, for example, the second annular inclined surface portion is formed so that the elevation angle is 15 degrees at the rising portion from the inner edge of the bottom surface portion, and the angle is increased toward the top portion so that the elevation angle is 60 degrees near the boundary with the connection portion. May be formed.
In other words, the first annular inclined surface portion and the second annular inclined surface portion do not have to be formed in a straight line shape in the cross-sectional shape shown in FIG. 3, but are formed in an arc shape that gently curves. Also good.

  Further, in order to increase the amount of light outward in the radial direction, it is effective to use the light of the light source arranged on the outer peripheral side rather than the inner peripheral side. The second annular inclined surface portion and the first annular inclined surface portion arranged inside and outside of the bottom surface portion are set to an angle within the above range, and the second annular inclined surface portion arranged inside and outside of the first bottom surface portion and the second bottom surface portion and the first As an angle outside the above-mentioned range with the one annular inclined surface portion, it is possible to secure a light amount to the front surface side above a certain level.

Further, in the present embodiment, the first annular inclined surface portion extending from the outer edge of the inner bottom surface portion of the two bottom surface portions adjacent to each other in the radial direction and the second annular inclined surface portion extending from the inner edge of the outer bottom surface portion. In this example, a connection portion is provided between the bottom surface portion and a protrusion having a trapezoidal cross section is formed between the bottom surface portion, and the first annular slope surface portion and the second annular slope surface portion are directly connected. You may make it form the mountain-shaped protrusion which made the boundary line of a 1st cyclic | annular inclined surface part and a said 2nd cyclic | annular inclined surface part a ridgeline between the said bottom face parts.
Moreover, the light reflecting plate of this invention can be made into various shapes other than the aspect illustrated above.

For the purpose of increasing the amount of light outward in the radial direction, the height of the trapezoidal or chevron-shaped protrusions, that is, the height of the light reflecting plate between the two bottom surface portions, increases from the inner edge side toward the outer edge side. It is preferable to make it low, and by doing in this way, it can suppress that an outer processus | protrusion inhibits that reflected light is irradiated outward from the inner side.
In addition, in order to gradually increase the amount of light outward in the radial direction from the inner side to the outer side of the light reflecting plate, the angle of the first annular inclined surface portion is decreased toward the outer side while the second annular shape is decreased. It is preferable to increase the angle of the inclined surface portion toward the outside.
In addition, when the angle of the second annular inclined surface portion is set to 15 degrees or more and 35 degrees or less, the reflected light emitted from the light source disposed on the inner bottom surface portion and reflected by the light diffusion member is reflected on the light reflecting plate. This is effective to reflect the light radially outward again, but the tendency to reflect forward the light emitted from the light source disposed on the bottom surface of the second annular inclined surface is increased.
Therefore, in order to increase the amount of light outward in the radial direction, it is preferable to set the angle of the second annular inclined surface portion to be higher than 35 degrees within a range of 15 degrees to 60 degrees.
In particular, since the light source is not planned to be arranged on the innermost second annular inclined surface portion, the angle is preferably more than 35 degrees and not more than 60 degrees for the above purpose.
Moreover, it is preferable that the angle of the outermost first annular inclined surface portion is substantially 0 degree in that light distribution of 180 degrees or more can be promoted with the light reflection plate as the center.

Such a light reflecting plate includes, for example, a light emitting device including a plurality of point light sources, a light diffusing member for diffusing reflected light reflected by the light reflecting plate in front of the light reflecting direction of the light reflecting plate, and The lighting device can be used in combination, and can be provided in the lighting device so that the light emitted from the point light source of the light emitting device can be reflected to one side.
More specifically, the light reflecting plate is attached to a light emitting device having a plurality of LEDs that are annularly arranged so as to form a quadruple concentric circle corresponding to the first bottom surface portion to the fourth bottom surface portion of the light reflecting plate. At the same time, a light diffusing member may be provided so as to face the light reflecting plate to constitute an illumination device having excellent light diffusibility.
As the light diffusing member, a so-called “light diffusing plate” having a flat plate shape or a curved plate shape can be adopted.
In addition, in order to diffuse light outside the light reflecting plate, the light diffusing material such as a cylindrical one having an inner diameter larger than that of the light reflecting plate or a dome shape covering all the side surfaces as well as the front side of the light reflecting plate It can be employed as a member.
Among these, it is preferable to employ a light diffusing plate or a dome-shaped light diffusing member for the illuminating device, and to diffuse light at least at a portion facing directly in front of the light reflecting plate.

The light reflecting plate includes an annular bottom surface in a plan view, a first annular inclined surface portion extending in an upward gradient from the outer edge of the bottom surface in the radial direction, and a radially inward direction from the inner edge of the bottom surface portion. And the second annular inclined surface portion extending upwardly toward the surface, and by arranging the LEDs of the light emitting device on the bottom surface portion with a circumferential interval, the first annular inclined surface portion The second annular inclined surface portion can be used as a reflecting surface for reflecting the light of the LED.
Moreover, since the elevation angle of the first annular inclined surface portion is more than 0 degree and not more than 30 degrees and the elevation angle of the second annular inclined surface portion is not less than 15 degrees and not more than 60 degrees, for example, the directivity angle is about 100 to 120 degrees. Even when mounted on a light emitting device equipped with the LED, light can be diffused over a wide range by using multiple reflection with the light diffusing member.

In order to exhibit excellent light diffusibility not only on the front surface side but also radially outward using such multiple reflection, a plurality of bottom surface portions are arranged concentrically as shown in the above example, In the illumination device in which the light diffusing member is disposed so as to face the light reflecting plate, the following light emitting device is used, and the point light source is concentrically disposed so as to correspond to the bottom surface portion. It is preferable to make it satisfy | fill 1).
(5 × H) ≦ P ≦ D (1)
Note that “D (mm)” in the relational expression (1) represents the distance from the point light source to the light diffusing member, and “H (mm)” is the two bottom surfaces adjacent to each other in the radial direction. The height of the light reflecting plate between the inner bottom surface portion and the outer bottom surface portion of the bottom surface portion is shown.
“P (mm)” represents the distance in the radial direction of the point light sources arranged concentrically along the bottom surface.
In addition, in the case where the point light source disposed on the bottom surface portion on the inner peripheral side and the point light source disposed on the outer peripheral side are shifted in the circumferential direction, the value of “P” is It is not determined by the length of the line segment connecting the inner and outer point light sources, but is determined by the distance between the ring drawn by the inner peripheral point light source and the ring drawn by the outer peripheral point light source.
That is, if there is no outer point light source on the straight line drawn from the center point of the light source arranged in a ring toward the point light source on the inner circumference side, the ring shape drawn by the outer point light source The value of “P” is determined by the distance between the intersection where the straight line intersects with the point light source on the inner periphery side.

  It is preferable to configure the lighting device so as to satisfy the relational expression (1). For example, when the lighting device is configured so that P <(5 × H) or D <(5 × H). There is a possibility that the shadow of the light reflection plate is likely to be formed on the surface side of the light diffusing member, and when D <P, there is a possibility that unevenness in light intensity may occur on the surface side of the light diffusing member between the part with the light source and the part with no light source. It is for having.

Moreover, in the point which can make such an illuminating device easy to manufacture, the fixing for fixing the said light reflecting plate to a light-emitting device by making the through-hole 11 of the bottom face part of a light reflecting plate correspond to LED arrangement | positioning. The part is preferably provided on the light reflecting plate.
For example, several dice cup-shaped recessed portions are provided in the first annular inclined surface portion or the like of each divided piece 1, and the recessed portions are provided so that the bottom portion is at the same vertical position as the bottom surface portion. In addition, a through hole for fixing with a fastener such as a screw or a rivet may be further formed at the bottom of the recessed portion to provide the fixing portion for fixing to the light emitting device.
Then, by fixing each divided piece at a predetermined position of the substrate of the light emitting device, the light source position of the light emitting device and the position of the through hole 11 provided in the bottom surface portion 10 of the light reflecting plate are aligned on the substrate surface. If the fixing position of the fixing portion is marked, the lighting device can be easily assembled by the light emitting device and the light reflecting plate.

Each split piece is provided with a surplus length at the part where the contour shape is linear, and when assembling the lighting device, the linear parts of the adjacent split pieces are vertically overlapped on the light emitting device. It is preferable that a gap is formed between adjacent divided pieces and light is prevented from leaking from the gap to the back side.
Moreover, after fixing the divided piece having the recessed portion to the light emitting device with a fastener or the like, the recessed portion is closed with a lid member or the like, and the light reflectivity of the first annular inclined surface portion is not impaired by the recessed portion. It is preferable to do so.

In addition, if it is a case where such an illuminating device is utilized for general indoor lighting, it will not specifically limit, For example, the curvature radius ("" of FIG. 2) of the inner edge side of the said light reflecting plate is mentioned. R21 ″) is about 100 mm to 200 mm, and the radial width of the light reflecting plate (“R22” in FIG. 2) is about 100 mm to 200 mm.
The width of the bottom surface portion in the radial direction is, for example, about 5 mm to 10 mm, and the distance between adjacent bottom surface portions (the pitch of the bottom surface portion in the radial direction) is 20 mm to 50 mm.
Furthermore, the height of the first annular inclined surface portion or the second annular inclined surface portion is, for example, about 3 mm to 15 mm.

In the present embodiment, the case where the light reflecting plate (divided piece) is formed of a thermoplastic resin sheet is exemplified in that it is easy to form such a three-dimensional shape, but the light reflecting plate of the present invention is illustrated. The forming material is not particularly limited, and a sheet material such as a metal sheet can also be used as the forming material for the light reflecting plate.
That is, the light reflecting plate of the present embodiment is vacuum formed into, for example, a foamed sheet made of polypropylene resin, polystyrene resin, or the like, a non-foamed sheet, or a laminated foamed sheet in which a foamed sheet and a non-foamed sheet are laminated. It can be formed by thermoforming such as pressure forming, vacuum pressure forming, press forming or the like, but it can also be formed by press forming or drawing on a metal sheet made of aluminum, stainless steel or the like.
Furthermore, the light reflecting plate of the present invention does not need to be formed into a sheet having a uniform thickness, and if a predetermined shape is given to the light reflecting surface side, the whole is made into a three-dimensional shape by injection molding or the like. It is also possible.

Moreover, in this embodiment, although the case where the light reflecting plate is configured by a plurality of divided pieces is illustrated in that it is easy to adjust an error occurring in the arrangement of the light sources of the light emitting device on the light reflecting plate side. The light reflecting plate of the present invention does not need to be configured by combining divided pieces, and may be integrally formed.
Furthermore, in the present embodiment, the case where the donut-shaped light reflecting plate is formed of divided pieces that are divided into four in the circumferential direction is illustrated, but the dividing direction may be the radial direction instead of the circumferential direction.
For example, the first bottom surface portion, the second bottom surface portion, and the inner and outer first annular inclined surface portions and the second annular inclined surface portion are integrally formed, and the third bottom surface portion, the fourth bottom surface portion, and the inside and outside The first annular inclined surface portion and the second annular inclined surface portion may be formed as separate integrated products, and may be divided into two large and small annular pieces.

  In the present embodiment, a light emitting device in which a plurality of LEDs are arranged in an annular shape and a light reflecting plate having an annular bottom surface in a plan view are exemplified. For example, a polygonal ring such as a regular hexagon or a square is illustrated. A light reflecting plate having a polygonal bottom surface used in a light emitting device in which a point light source is disposed is also within the scope of the present invention.

  In addition, it goes without saying that various modifications other than the above-described examples can be adopted for the light reflector and the lighting device of the present invention.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
(Examples 1-4, Comparative Examples 1-5)
(Evaluation method)
For the evaluation, a combination of the light emitting device S and the light reflecting plate 1x as shown in FIG. 4 ((a) schematic plan view, (b) ZZ schematic cross sectional view in the evaluation of Example 1) is used. It was.

(Light emitting device)
First, prior to the evaluation, the board dimensions are 245 mm × 132 mm, and 4 rows × 7 pieces (total of 28 pieces) at a pitch of 35 mm vertically and horizontally (28 pieces in total, “SMD LED Model # LU6-FWH1-03-N5-NS” manufactured by Cree) , Chip size: 3.3 mm × 3.5 mm × 2 mmH, radiation angle: 180 °, directivity angle (angle at which central light brightness is half brightness value = half-value angle): 120 ° A light emitting device S having an operating power of 2.8 W (0.1 W / piece) was prepared.

(Light reflector)
A laminated foam sheet in which a thermoplastic resin non-foamed sheet is laminated and integrated on one surface of a thermoplastic resin foam sheet (thickness: 0.8 mm, overall density: 0.8 g / cm ³ , light rays on the thermoplastic resin non-foamed sheet surface) The total reflectance is 98.5%, the diffuse reflectance is 96.3%, and the ratio of the diffuse reflectance to the total light reflectance is 97.8%). By molding, it was produced so as to have substantially the same contour shape as the light-emitting device and to have the dimensions described in Table 1 below.
Here, four rows of linear bottom surfaces extending in the longitudinal direction are formed at a pitch of 35 mm so as to correspond to the respective LED rows of the light emitting device, and φ6 mm for allowing the LEDs to be inserted into the bottom portion from the back side. Through-holes were formed.

(Evaluation sample)
The light reflecting plate 1x was attached to the light emitting device S so as to expose the LED (symbol A) of the light emitting device S from the through hole provided in the bottom surface portion 10x, and used as an evaluation sample.
As can be seen from FIG. 4B, in this evaluation, one long side of the light emitting device S having a rectangular shape in plan view (the right side in FIG. 4B, the right side of the front view, the light source fourth row side). The other long side (the left side of the front view in FIG. 4B, the light source first row side) is assumed as the center side of the lighting device.
That is, the value of “α” in the first column of Table 1 corresponds to, for example, the elevation angle of the second annular inclined surface portion extending from the inner edge of the first bottom surface portion of the light reflecting plate formed by combining the divided pieces of FIG. “Β” corresponds to the elevation angle of the first annular inclined surface portion extending from the outer edge of the first bottom surface portion.
“Ha” and “Hb” are respectively a vertical distance (height) from the first bottom surface portion to the top of the second annular inclined surface portion and a vertical distance (height) to the top of the first annular inclined surface portion. “La” and “Lb” correspond to the horizontal distance from the light source position to the top of the second annular inclined surface portion and the horizontal distance to the top of the first annular inclined surface portion.
In the following, the right side (fourth row side) of FIG. 4B is also referred to as the outside of the lighting device, the outside of the light emitting device, and the left side (first row side) of FIG. Also referred to as the center side, the center side of the light emitting device, or the like.

(Lighting device)
Next, as shown in FIG. 5, a light diffusing member E having a ceiling wall portion having a rectangular shape of 325 mm × 172 mm and further including a side wall portion that hangs at right angles from one of the long sides of the ceiling wall portion is prepared. The light-emitting device S equipped with the reflector 1x is placed on a horizontal table, the side wall E2 is 22.5 mm away from the light-emitting device S, and the ceiling wall extends from a light source (LED). The lighting device was simulated by covering the upper surface side and the outer side of the light emitting device S with the light diffusing member E so that the portion E1 is in a state of being separated by 60 mm.
The light diffusion member E used at this time had a thickness of 3 mm and a light transmittance of 58%.

(Measurement of front and side illumination)
Of the area (245 mm × 132 mm) where the light emitting device S is projected onto the ceiling wall E1 of the light diffusing member E, a central area of 240 mm × 120 mm is divided into four equal parts in the longitudinal direction and in the short direction. Dividing into two equal parts, eight measurement regions shown in (1) to (8) in FIG.
Similarly, an area of 240 mm × 40 mm is set above the area where the light emitting device S is projected onto the side wall E2 of the light diffusing member E, and this is divided into 4 equal parts in the longitudinal direction and 2 etc. in the lateral direction. Thus, eight measurement areas indicated by (A) to (H) in FIG. 5B were set.
In a state where the light emitting device S is energized and the LED is caused to emit light, an illuminance meter (“Digital Illuminance” manufactured by Konica Minolta Co., Ltd.) is provided at each central portion of the measurement region (1) to (8) of the ceiling wall portion E1 of the light diffusion member E The light receiving portion of the total T-1 ”) was vertically contacted from above and the illuminance was measured, and the arithmetic average value was defined as the front illuminance of the lighting device.
Similarly, the illuminance is measured by bringing the light-receiving unit of the illuminometer into contact with the center of each of the measurement areas (a) to (h) of the side wall E2 from the front, and the arithmetic average value is calculated as the side illuminance of the lighting device. It was.
In the evaluation of the side illuminance, when the side illuminance of Comparative Example 5 employing a simple flat light reflecting plate as 100% is set to 100% as will be described later, the side surface of Comparative Example 5 is shown in each Example and Comparative Example. The amount of increase / decrease in the illuminance was calculated from the measurement results.
As a result, a case where the side illuminance increased by 10% or more with respect to Comparative Example 5 was determined as a pass “◯”, and the increase in side illuminance was less than 10%, or the side illuminance decreased compared to Comparative Example 5. The case where it has done is determined as a failure “×”.

(Evaluation of uniform visibility)
The light emission state in the ceiling wall part E1 of the lighting device was evaluated based on visual judgment.
In addition, the case where light emission unevenness was hardly visually recognized was determined as “uniform visibility good (◯)”, and the case where a linear light emission unevenness (shadow) was slightly visually recognized was determined as “uniform vision approval (Δ)”.
In addition, a case where clear linear light emission unevenness (shading) was visually recognized was determined as “uniformly invisible (x)”.

(Comprehensive judgment)
Based on the evaluation results of side illuminance and uniform visibility, comprehensive judgment was performed.
Here, the case where the illuminance on the side surface is a pass judgment “◯” and the uniform visibility is “good (◯)” or “possible (Δ)” is determined as a comprehensive judgment “pass (○)”, and any of them is judged as a failure. About what (x) was obtained, it was set as comprehensive determination "failure (x)."
These evaluation results are shown together in Table 1 below.

In Comparative Example 5, a simple flat plate provided only with a through hole for allowing the LED to pass through the laminated foam sheet before thermoforming was used as the light reflecting plate.
In Example 3 and Comparative Example 1, the value obtained by adding the value of “Lb” to the value of “La” is the same as the LED column spacing (35 mm). However, as shown in FIG. Indicates that there is no equivalent to the connecting portion 40x.

In Comparative Example 5 using this flat light reflecting plate and other Comparative Examples, the side illumination is low and uniform visibility is difficult to obtain.
On the other hand, in the examples, the conditions of (5 × Ha), (5 × Hb) ≦ P (35 mm) ≦ D (40 mm) are satisfied, and the result is excellent in lateral irradiation and excellent in uniform visibility. Is obtained.
That is, it can be seen that the present invention can provide a light reflector and a lighting device capable of diffusing light over a wide range.

1: Divided pieces (of light reflection plate), 10: bottom surface portion, 20: first annular inclined surface portion, 30: second annular inclined surface portion, 40: connection portion, 100: light diffusion plate

Claims (6)

  An annular bottom surface portion in plan view, a first annular inclined surface portion extending in an upward gradient from the outer edge of the bottom surface portion in the radial direction, and an upward gradient inward from the inner edge of the bottom surface portion in the radial direction. And a plurality of point light sources are disposed on the bottom surface portion with an interval in the circumferential direction, and the first annular inclined surface portion and the second annular inclined surface portion are Used as a reflecting surface for reflecting the light of the point light source, the elevation angle of the first annular inclined surface portion is more than 0 degree and not more than 30 degrees, and the elevation angle of the second annular inclined surface portion is 15 degrees or more and 60 degrees. A light reflector characterized by the following.   The plurality of bottom surface portions are arranged concentrically, and the first annular inclined surface portion extending from the outer edge of the inner bottom surface portion and the second annular inclined surface portion extending from the inner edge of the outer bottom surface portion are directly or these The light reflecting plate according to claim 1, wherein the light reflecting plates are connected via a connecting portion having an annular shape in plan view arranged concentrically with the bottom portion.   The light reflecting plate according to claim 1 or 2, wherein the thermoplastic resin sheet is thermoformed.   The light reflecting plate according to any one of claims 1 to 3, wherein the light reflecting plate can be disassembled into a plurality of divided pieces. A light emitting device including a plurality of point light sources, a light reflecting plate, and a light diffusing member; the light emitted from the point light source of the light emitting device is reflected to one surface side of the light reflecting plate; An illumination device configured to be able to diffuse with the light diffusing member disposed in front of the light reflecting direction of the light reflecting plate,
The light reflecting plate includes an annular bottom surface in a plan view, a first annular inclined surface portion extending in an upward gradient from the outer edge of the bottom surface in the radial direction, and a radially inward direction from the inner edge of the bottom surface portion. And a second annular inclined surface portion extending upwardly toward the surface, and point light sources of the light emitting device are arranged on the bottom surface portion with a space in the circumferential direction, and the first annular inclined surface portion and the second An annular inclined surface portion is used as a reflecting surface for reflecting the light of the point light source, an elevation angle of the first annular inclined surface portion is more than 0 degree and not more than 30 degrees, and the second annular inclined surface portion. The elevation angle of is 15 degrees or more and 60 degrees or less. A plurality of the bottom surface portions are concentrically disposed on the light reflecting plate, the point light sources are concentrically disposed on the light emitting device so as to correspond to the bottom surface portion, and the light diffusion member is the light The lighting device according to claim 5, wherein the lighting device is disposed so as to face the reflecting plate, and the light diffusing member, the light reflecting plate, and the light emitting device are provided so as to satisfy the following relational expression (1).
(5 × H) ≦ P ≦ D (1)
(However, “D (mm)” represents a distance from the point light source to the light diffusing member, and “H (mm)” represents an inner bottom surface portion and a bottom surface portion disposed outside the bottom surface portion. ("P (mm)" represents the distance in the radial direction of the point light sources arranged concentrically along the bottom surface portion.)

Images