JP6018569B2 - Diffusion sheet for LED lighting and LED lighting apparatus using the same - Google Patents

Description

  The present invention relates to a diffusion sheet disposed so as to cover an LED in a lighting fixture using a light emitting diode (hereinafter referred to as an LED), and more specifically, has high transmissivity and eliminates the bright spot of the LED. The present invention relates to a diffusion sheet capable of bringing the impression of emitted light close to that of a fluorescent lamp and an LED lighting apparatus using the diffusion sheet.

  Since LEDs have low power consumption and high luminous efficiency, their use as energy-saving light bulbs has been spreading in recent years. On the other hand, LED is basically a point light source and has high directivity of light, so when used as illumination, a particularly bright spot called a bright spot is generated. There is discomfort that irritate the eyes. In order to eliminate such drawbacks, when using LEDs as illumination, light was used as scattered light, such as by shielding direct light with a milky white cover containing a diffusing agent. Light transmittance is low and it becomes dark.

  As a means for solving this drawback, a lighting fixture in which an LED is covered with a film having high optical anisotropy has been proposed (see Patent Document 1). According to this luminaire, the film has a high transmissivity, and the discomfort that stimulates the eyes by diffusing the bright spots is somewhat reduced. However, the light is only diffused in one direction, and a linear lamp image remains, and there is a large difference in brightness between the position where the diffused light is directly emitted and other positions, so when looking directly at this lamp I still feel uncomfortable.

Utility Model Registration No. 3163988

  In view of such circumstances, the present invention eliminates the above-mentioned problems of the prior art, has high transmissivity, can sufficiently eliminate bright spots that stimulate eyes, and brings the impression of emitted light closer to a fluorescent lamp. An object of the present invention is to provide a diffusion sheet for LED lighting and a method for using the same.

The present invention is characterized by the following (1) to ( 7 ).
(1) The present invention is a diffusion sheet provided with a lenticular concavo-convex structure in which a plurality of cylindrical lens-shaped unit lens rows are arranged in parallel on the front and back surfaces,
The ridge line direction of the unit lens array on the front side and the ridge line direction of the unit lens array on the back surface intersect at an intersection angle of 60 ° to 90 ° ,
At the rate of pitch of 6 or less to the height of the unit lens array, a diffusion sheet for LED luminaire pitch, characterized in der Rukoto below 700μm contents.

( 2 ) The present invention includes the above diffusion sheet containing the diffusing agent so that the total light transmittance is 85% or more and the haze is 85% or more.

( 3 ) The present invention includes the above diffusion sheet in which the diffusing agent is a crosslinked polyacrylate.

( 4 ) The present invention comprises a linearly arranged LED and the diffusion sheet according to any one of (1) to (3) above ,
The diffusion sheet is a contents installed Tei Ru LED luminaire as the arrangement direction of the ridge line direction and LED unit lens array surface made on the outer side is parallel over the LED arranged in the straight line.

( 5 ) The present invention includes the above-described LED lighting fixture which is an indoor lighting fixture .

( 6 ) The present invention includes a plurality of LEDs arranged linearly and the diffusion sheet according to any one of the above (1) to (3 ), and the diffusion sheet is placed on the LEDs arranged linearly. as the array direction of the ridge line direction and LED unit lens array of on the outside surface to the contents Tei Ru L ED luminaire is curved to be installed so as to Cartesian.

( 7 ) The present invention includes the above-described LED lighting fixture which is a tabletop lighting fixture .

  According to the diffusion sheet of the present invention, a lenticular-shaped uneven structure in which a plurality of cylindrical lens-shaped unit lens rows are arranged in parallel is provided on both the front and back surfaces, and the ridge line direction of the unit lens rows on the front surface side and the back surface side is 30 ° to Since it is configured to intersect at an intersection angle of 90 °, the light transmittance is high, the luminescent spot is weakened to the extent that the light emitted from the LED is diffused in two directions and does not irritate the eyes, and moiré is also generated The unevenness of the emitted light is reduced.

  When the ratio of the pitch to the height of the unit lens array is 6 or less, the pitch of the unit lens array is 700 μm or less, and the intersection angle between the front and back unit lens arrays is 60 ° to 90 °, the LED shape is almost visible. It disappears, and the appearance of the surface of the LED illumination becomes closer to a fluorescent lamp.

  By containing the diffusing agent so that the total light transmittance is 85% or more and the haze is 85% or more, the irritation of the eyes due to the bright spots is further reduced without much lowering the illuminance. The lamp image can be further eliminated. As the diffusing agent, a crosslinked polyacrylate is preferred.

  When the diffusion sheet of the present invention is installed on a linearly arranged LED, the ridge line direction of the unit lens array on the outer surface is installed so that it is substantially orthogonal to the LED arrangement direction. Even when the diffusion sheet of the invention is curved along an axis substantially parallel to the LED arrangement direction, the light emitted from the LED is emitted in the lateral direction (direction substantially orthogonal to the LED arrangement direction, the same applies hereinafter). Therefore, the illuminance directly under the illumination using the diffusion sheet is high, and it is excellent as desk lighting.

  When the diffusion sheet of the present invention is installed on a linearly arranged LED, it is curved along an axis substantially parallel to the LED arrangement direction, and the ridge line direction of the unit lens array on the outer surface is the LED. By installing the LED so as to be substantially parallel to the arrangement direction, the light emitted from the LEDs can be easily emitted in the horizontal direction, so the difference between the illuminance directly below the illumination using the diffusion sheet and the ambient illuminance is reduced. It is excellent as lighting that illuminates the entire room.

FIG. 1 is a conceptual explanatory view showing a diffusion sheet for LED illumination. FIG. 2 is a conceptual explanatory view showing the cross-sectional shape of the unit lens array in the LED illumination diffusion sheet of the present invention. Fig.3 (a) is a schematic explanatory drawing which shows an LED lighting fixture, (b) is AA sectional drawing of (a). 4 (a) and 4 (b) are schematic explanatory views showing LED lighting fixtures different from those in FIG. Fig.5 (a) is a schematic explanatory drawing which shows the LED lighting fixture of Example A1, (b) is BB sectional drawing of (a), (c) is CC sectional drawing of (a). . FIG. 6 is a photograph showing a lamp image of Example A1. FIG. 7 is a photograph showing a lamp image of Example A5. FIG. 8 is a photograph showing a lamp image of Comparative Example A2. FIG. 9 is a photograph showing a lamp image of Comparative Example A3. FIG. 10 is a photograph showing a lamp image of Comparative Example A4. FIG. 11 is a photograph showing a lamp image of Comparative Example B1. FIG. 12 is a photograph showing a lamp image of a control example.

  For example, as shown in FIG. 1, the diffusion sheet 1 in the present invention is provided with a lenticular concavo-convex structure in which a plurality of cylindrical lens-shaped unit lens arrays 2 are arranged in parallel on the front and back surfaces. The ridge line direction and the ridge line direction of the unit lens array on the back side intersect with each other at an intersection angle of 30 ° to 90 °.

In the present invention, the cylindrical lens shape includes not only a so-called cylindrical shape in which the cross-sectional shape is a columnar shape made up of an arc and a straight line but also a columnar shape in which the cross-sectional shape is bent in one direction such as an elliptical arc or a parabola. The lenticular shape refers to a shape in which the cylindrical lens-like unit lens rows are arranged in parallel with each other without a gap.
Further, in the present invention, “substantially orthogonal” and “substantially parallel” mean socially orthogonal and parallel, and unlike mathematical orthogonal and parallel means that an error of about 5 ° is allowed.

  The diffusion sheet of the present invention is provided with a lenticular concavo-convex structure in which a plurality of cylindrical lens unit lens arrays are arranged in parallel on the front and back surfaces of the diffusion sheet. The method of providing the concavo-convex structure on both the front and back surfaces is not particularly limited. For example, in a method in which the resin extruded into a sheet is sandwiched between two metal cooling rolls, a female mold having an concavo-convex structure is formed on the surfaces of both metal cooling rolls. In the method of engraving and pressing the resin extruded into a sheet shape between a metal cooling roll and a rubber roll, an uneven structure female die is engraved on the surface of the metal cooling roll, and an uneven structure is formed on the rubber roll side. A method of placing a mold film on which a female mold is transferred, a method of bonding two optical sheets with a concavo-convex structure engraved on one side with an adhesive resin, and a sheet of concavo-convex structure engraved only on one side A method of stacking the optical sheets and fastening them with a fastener or the like can be exemplified.

  The resin used as the material of the diffusion sheet in the present invention is not particularly limited as long as it is a transparent resin. For example, polyolefins such as acrylic, polycarbonate, polystyrene, polyvinyl chloride, polyethylene, polypropylene, polymethylpentene, cyclic polyolefin, polyethylene Examples thereof include polyesters such as terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamide, polyarylate, and polyimide.

In the present invention, a haze may be increased by adding a diffusing agent or the like to the resin used as a raw material. Specifically, all parts of the diffusion sheet may be made of a resin containing a diffusing agent, or a resin containing a diffusing agent may be used as an adhesive for laminating two optical sheets. Alternatively, an optical sheet in which a concavo-convex structure is provided only on one side with a resin containing a diffusing agent may be prepared and bonded with a normal resin.
As the diffusing agent, inorganic particles such as aluminum silicate, calcium silicate, silica, alumina and calcium carbonate, organic particles such as cross-linked polyacrylate, cross-linked MS resin (MMA and styrene copolymer), silicon resin, etc. Can be illustrated.
An appropriate blending amount or the like varies depending on the type of transparent resin and the type of diffusing agent, and thus cannot be specified unconditionally. The degree is preferably about 0.1 to 5.0 parts by weight, preferably 0.5 to 3.0 parts by weight, based on 100 parts by weight of the transparent resin of the diffusion sheet. With such a blending amount, the light diffused by the diffusion sheet of the present invention is further diffused, the eye irritation caused by the bright spots is further reduced, moire and lamp images are preferably eliminated, and the illuminance is also reduced. It fits to the extent you don't mind.

In the present invention, the ridge line directions of the unit lens rows constituting the concavo-convex structure intersect each other at an intersection angle of 30 ° to 90 °, preferably 60 ° to 90 °, on the front surface and the back surface. . In this way, the translucency is higher than when using a diffusing plate containing a diffusing agent, so that it stimulates the eyes compared to when using a diffusing sheet with acrylic beads attached to the surface. The bright spot can be effectively weakened, and the unevenness of light can be reduced as compared with the case where a film having high optical anisotropy is used.
If the angle of intersection of the front and back unit lens arrays in the ridge line direction is less than 30 °, the bright spot of the LED cannot be sufficiently diffused and moire is generated, so that the LED is viewed through the diffusion sheet. May cause irritation to eyes.

  In the present invention, the ratio P / H of the pitch P to the height H of the unit lens array is 6 or less, preferably 5 or less, the pitch P is 700 μm or less, preferably 500 μm or less, and more preferably 450 μm or less. By making the crossing angle in the ridge line direction of the unit lens row of 60 ° to 90 °, the light emitted from the LED is more preferably diffused and almost no bright spots are generated, and the LED lamp image can be eliminated. . As shown in FIG. 2, in the present invention, the pitch P refers to the parallel interval of the unit lens arrays 2, and the height H refers to the difference in altitude between the highest position and the lowest position in the unit lens array 2. . The lower limit of the ratio P / H of the pitch P to the height H of the unit lens array is usually preferably about 1.5, and the lower limit of the pitch P is preferably about 10 μm.

  The diffusion sheet of the present invention as described above is used by covering the LED. In particular, as shown in FIG. 3, the LEDs 4 are linearly arranged on the substrate 3 a and the diffusion sheet 1 is arranged on the surface side thereof, and the diffusion sheet 1 is arranged along an axis substantially parallel to the arrangement direction of the LEDs 4. If the LED 4 is covered together with the substrate 3a with the diffusion sheet 1 of the present invention by curving, the external appearance becomes like a fluorescent lamp, and there is no sense of incongruity in terms of design.

When the LEDs arranged in a straight line are covered with the diffusion sheet 1 of the present invention, the directivity of the emitted light can be adjusted by changing the installation angle and the curvature of the diffusion sheet 1.
That is, light with very strong directivity is emitted from the LED 4, but the light from the LED 4 is not completely diffused when the diffusion sheet 1 of the present invention is not curved. Light with strong directivity is emitted. On the other hand, when the diffusion sheet 1 of the present invention is curved, if it is curved along an axis parallel to the ridge line direction of the unit lens array on the emission surface (the surface that becomes the outside when installed on the LED 4), Since the emitted light is diffused in a direction in which the diffusion sheet 1 is curved, light suitable for illuminating a wide range is irradiated. On the other hand, when it is curved along the axis perpendicular to the ridge line direction of the unit lens array on the exit surface, the directivity of the emitted light does not change much compared to the case where it is not curved, The directivity remains strong.

Using the properties of the diffusion sheet of the present invention as described above, a desk lamp and an indoor lighting apparatus can be formed using the linearly arranged LEDs and the diffusion sheet of the present invention.
Table-top lighting fixtures generally have a light source arranged near the eye level of the user who is seated, and there are many opportunities for the user to look directly at the light source from a close range, so there is little light emitted in the lateral direction. It is preferable that the directivity is strong. Therefore, when used for desktop use, the diffusion sheet of the present invention may be used without being curved, or may be curved along the 90 ° axis and the ridgeline direction of the unit lens array on the exit surface.
In particular, when LEDs are arranged in a straight line and used in the same manner as a fluorescent lamp, the diffusion sheet of the present invention is wound around the LED arrangement or the LED is arranged for design or structural purposes. In many cases, it is required to use the diffusion sheet in a state where the edge of the diffusion sheet is fixed and curved in the vicinity of the edge in the width direction of the substrate, but even in such a case, as shown in FIG. If the unit lens array is installed so that the ridge direction of the unit lens array is substantially orthogonal to the LED arrangement direction, and it is curved along an axis parallel to the LED arrangement direction, it can emit light with high directivity. LED lighting can be obtained and design or structural requirements can be met.

On the other hand, the indoor lighting device is installed near the ceiling of the room and illuminates the entire room. It is desirable to illuminate the entire room including not only directly under the lighting but also the periphery thereof, that is, it is preferable that the diffusibility is strong. Therefore, when used for an indoor lighting apparatus, the diffusion sheet of the present invention may be curved along an axis parallel to the ridge line direction of the unit lens array on the exit surface.
In particular, when the LEDs are arranged in a straight line and used in the same manner as a fluorescent lamp, the diffusion sheet of the present invention is installed so that the ridge line direction of the unit lens array on the exit surface is substantially parallel to the LED arrangement direction. If the LED is curved along an axis substantially parallel to the LED arrangement direction, an indoor lighting device having a small difference in illuminance between directly under and around the illumination can be obtained.
3 and 5, the LEDs are arranged in a single straight line, but in the present invention, as shown in FIGS. 4A and 4B, a plurality of straight lines such as two or three are provided. May be arranged in
Of course, when it is not necessary to imitate the shape of the fluorescent lamp in design, the LEDs may be arranged not only in a straight line but also in a matrix.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited only to these Examples.

(About the resin used)
In the following Examples, as a transparent resin, polycarbonate transparent resin “Panlite L-1225Y (trade name)” manufactured by Teijin Chemicals Ltd. (light transmittance of resin based on ASTM D1003: 90%, haze: 3%, Hereafter, it is simply referred to as a transparent resin), and as a diffusible resin, a transparent resin of polycarbonate “Panlite ML-2203 (trade name)” in which a diffusion material manufactured by Teijin Chemicals Ltd. is blended (light transmission of resin based on ASTM D1003) Rate: 89%, haze: 88%, hereinafter simply referred to as diffusible resin), as a highly diffusible resin, polycarbonate transparent resin “Panlite ML-1105 (product) Name) ”(light transmittance of resin based on ASTM D1003: 54%, haze: 87%, hereinafter simply referred to as highly diffusible resin) It was used alone.

(Manufacture of diffusion sheet)
Example 1
In a method in which a transparent resin is extruded into a sheet form from a die at a resin temperature of melt extrusion of 295 ° C., and the extruded sheet-shaped molten resin is narrowed between a metal cooling roll and a rubber roll, And a release sheet (molding sheet) in which a concavo-convex structure on the back side was engraved on the rubber roll side to produce a diffusion sheet.
The concavo-convex structure has a pitch of 430 μm and a height of 111 μm on both the front side and the back side. The intersection angle between the ridge line direction of the front-side unit lens array and the ridge line direction of the back-side unit lens array is 90 °.

Example 2
A diffusion sheet was obtained in the same manner as in Example 1 except that the pitch and height of the unit lens rows were 50 μm and 18 μm, respectively.

Example 3
A diffusion sheet was obtained in the same manner as in Example 1 except that the pitch and height of the unit lens rows were 25 μm and 11 μm, respectively.

Example 4
A diffusion sheet was obtained in the same manner as in Example 1 except that the pitch and height of the unit lens array on the back side were 25 μm and 11 μm, respectively.

Example 5
A diffusion sheet was obtained in the same manner as in Example 1 except that the resin used was changed to a diffusible resin and the pitch and height of the unit lens rows were changed to 337 μm and 84 μm, respectively.

Example 6
In a method in which a transparent resin is extruded into a sheet form from a die at a resin temperature of melt extrusion of 295 ° C., and the extruded sheet-shaped molten resin is narrowed between a metal cooling roll and a rubber roll, A lens sheet was manufactured by engraving the female mold. The pitch of the concavo-convex structure is 193 μm and the height is 57 μm.
On the other hand, a diffusible resin was extruded into a sheet form from a die at a resin temperature of melt extrusion of 295 ° C., and a flat sheet was produced by a method in which the extruded sheet-shaped molten resin was narrowed between a metal cooling roll and a rubber roll.
The diffusion sheet of Example 6 was obtained by pasting the lens sheet on both sides of the flat sheet produced as described above so that the concavo-convex structure was on the outside. The intersection angle between the ridge line direction of the front-side unit lens array and the ridge line direction of the back-side unit lens array is 90 °.

Example 7
A diffusion sheet was obtained in the same manner as in Example 6 except that the lens sheet was made of a diffusible resin, the flat sheet was made of a transparent resin, the unit lens array pitch was 252 μm, and the height was 67 μm.

Example 8
In a method in which a transparent resin is extruded into a sheet form from a die at a resin temperature of melt extrusion of 295 ° C., and the extruded sheet-shaped molten resin is narrowed between a metal cooling roll and a rubber roll, A lens sheet for the surface side was manufactured by engraving the female mold. The unit lens array has a pitch of 430 μm and a height of 111 μm.
On the other hand, a lens sheet for the back side was manufactured in the same manner as the lens sheet for the front side except that the pitch of the unit lens rows was 25 μm and the height was 11 μm.
The lens sheets manufactured as described above were overlapped so that the concavo-convex structure was on the outside and the intersection angle of each unit lens row in the ridge line direction was 90 ° to obtain a diffusion sheet.

Example 9
A diffusion sheet was obtained in the same manner as in Example 1 except that the pitch and height of the unit lens rows were 163 μm and 26 μm, respectively.

Example 10
A diffusion sheet was obtained in the same manner as in Example 1 except that the pitch and height of the unit lens rows were 796 μm and 200 μm, respectively.

Example 11
A diffusion sheet was obtained in the same manner as in Example 1 except that the angle of intersection between the ridge line direction of the front unit lens array and the ridge line direction of the back unit lens array was set to 75 °.

Example 12
A diffusion sheet was obtained in the same manner as in Example 1 except that the crossing angle between the ridge line direction of the front unit lens array and the ridge line direction of the back unit lens array was 60 °.

Example 13
A diffusion sheet was obtained in the same manner as in Example 1 except that the crossing angle between the ridge line direction of the front unit lens array and the ridge line direction of the back unit lens array was 45 °.

Example 14
A diffusion sheet was obtained in the same manner as in Example 1 except that the crossing angle between the ridge line direction of the front unit lens array and the ridge line direction of the back unit lens array was 30 °.

Comparative Example 1
A diffusion sheet was obtained in the same manner as in Example 1 except that the crossing angle between the ridge line direction of the front unit lens array and the ridge line direction of the back unit lens array was 15 °.

Comparative Example 2
A diffusion sheet was obtained in the same manner as in Example 1 except that the ridge line direction of the unit lens array on the front surface side and the ridge line direction of the unit lens array on the back surface side were made parallel.

Comparative Example 3
A commercially available diffusion sheet (Ewa Co., Ltd., trade name: Opulse BS-913, total thickness: 270 μm, HAZE: 89%) with acrylic beads attached to the surface of the PET film was used as the diffusion sheet.

Comparative Example 4
A highly diffusible resin is extruded into a sheet form from a die at a resin temperature of melt extrusion of 295 ° C., and a flat sheet is produced by a method in which the extruded sheet-shaped molten resin is compressed between a metal cooling roll and a rubber roll, and then diffused. A sheet was used.

Example A1
As shown in FIG. 5, the substrate 3a in which the LEDs 4 are linearly arranged, the reflection plate 3b extending obliquely upward from the edge of the substrate 3a, and the diffusion sheet provided at the edge of the reflection plate 3b A lighting fixture having a mounting portion 3c is prepared, and the diffusion sheet of Example 1 is arranged so that the ridge line direction of the outer unit lens array is orthogonal to the LED arrangement direction and along an axis substantially parallel to the LED 4 arrangement direction. Then, the diffusion sheet 1 was attached so as to be curved to obtain a lighting fixture. However, the unit lens array of the diffusion sheet 1 shown in FIG. 5 is a schematic one, and the actual unit lens array is much smaller than that shown in the figure, and is difficult to distinguish with the naked eye.
Table 1 shows the angle in the ridge line direction of the unit lens array with respect to the LED arrangement direction, the pitch and height of the unit lens array, together with those of other examples and comparative examples.
About this lighting fixture, it measured and determined about direct illumination intensity, the presence or absence of the irritation | stimulation (bright spot) with respect to eyes, the presence or absence of moire, and the presence or absence of the LED lamp image. The measurement / judgment results are shown in Table 1 together with those of other examples and comparative examples.

Examples A2 to A14, Comparative Examples A1 to A4
Except having used the diffusion sheet of Examples 2-14 and Comparative Examples 1-4, it was set as the lighting fixture like Example A1.

Example B1
A lighting fixture was obtained in the same manner as in Example A1 except that the ridge line direction of the outer unit lens array was parallel to the LED arrangement direction.

Comparative Example B1
A lighting fixture was obtained in the same manner as in Example B1 except that the diffusion sheet of Comparative Example 2 was used.

Control Example A lighting apparatus was obtained in the same manner as in Example A1, except that no diffusion sheet was used.

Direct illuminance measurement:
As a measuring device, it is 38cm in length, 57cm in height, 75cm in height, without a bottom surface and a box with a measurement window opened in the center of the top surface and painted inside black, and an illuminometer attached to the measurement window (all-in-one digital) A measuring box made of Multimeter MT-8210 (manufactured by Mother Tool Co., Ltd.) was used.
Turn on the lighting fixtures of Examples, Comparative Examples, and Controls on the desk with the lamps facing upwards, let them stand for 30 minutes or more to stabilize the amount of light, and make the illuminance meter directly above the lighting fixtures. The measurement box was put on a lighting fixture, and the illuminance was measured.

Presence or absence of eye irritation (bright spot):
The lighting apparatus was installed sideways, and observed with the naked eye from a position 3 m away, and five panelists visually judged whether the stimulus to the eyes was close to the case of directly viewing the LED or the fluorescent lamp. Evaluation was made according to the following criteria based on the number of panelists who answered that they were close to LED.
○: 0 people △: 1-2 people ×: 3-5 people

Existence of moiré:
The lighting apparatus was installed sideways, and observed with the naked eye from a position 3 m away, and whether or not moire could be observed was visually judged by five panelists. The evaluation was made according to the following criteria based on the number of panelists who were able to observe moire.
○: 0 people △: 1-2 people ×: 3-5 people

Existence of LED lamp image:
The luminaire was installed sideways, and observed with the naked eye from a position 3 m away, and whether or not the position of the LED could be determined was visually judged by five panelists. The evaluation was made according to the following criteria according to the number of panelists who could discriminate the LED position.
○: 0 people △: 1-2 people ×: 3-5 people

  6 to 12 show Example A1 (FIG. 6), Example A5 (FIG. 7), Comparative Example A2 (FIG. 8), Comparative Example A3 (FIG. 9), Comparative Example A4 (FIG. 10), and Comparative Example. The photograph of the lamp image of each lighting fixture of B1 (FIG. 11) and a symmetrical example (FIG. 12) is shown. From this photograph, it can be seen that in the lighting fixtures of Examples A1 and A5 of the present invention, not only irritation to the eyes is reduced, but also the LED lamp image can be suitably erased. In addition, although the lamp image also disappears in the lighting fixture of Comparative Example A3, since a thick and highly diffusible flat sheet is used, the light transmittance is low and the effect of the present invention is not achieved.

  As described above, in the LED illumination diffusion sheet and the luminaire using the same according to the present invention, the ridge line directions of the unit lens rows on the front surface side and the back surface side intersect at an intersection angle of 30 ° to 90 °. Therefore, the light transmittance is high, the bright spot of the LED can be eliminated, and the impression of emitted light can be brought close to that of a fluorescent lamp, which is useful.

DESCRIPTION OF SYMBOLS 1 Diffusion sheet 2 Unit lens array 3 LED illumination 3a Board | substrate 3b Reflector 3c Diffusion sheet attaching part 4 LED
P pitch H height

Claims (7)

A diffusion sheet provided with a lenticular concavo-convex structure in which a plurality of cylindrical lens-shaped unit lens rows are arranged in parallel on the front and back surfaces,
The ridge line direction of the unit lens array on the front side and the ridge line direction of the unit lens array on the back surface intersect at an intersection angle of 60 ° to 90 ° ,
Unit ratio of pitch to height of the lens array is 6 or less, the diffusion sheet for LED luminaire pitch, characterized in der Rukoto below 700 .mu.m. The diffusion sheet according to claim 1, comprising a diffusing agent so that the total light transmittance is 85% or more and the haze is 85% or more. The diffusion sheet according to claim 2 , wherein the diffusion agent comprises a crosslinked polyacrylate. The LED comprises a linear array of LEDs and the diffusion sheet according to any one of claims 1 to 3 ,
LED lighting apparatus, wherein the diffusion sheet and the array direction of the ridge line direction and LED unit lens array surface becomes outside is installed in parallel Tei Rukoto over the LED arranged in the straight line . LED lighting apparatus according to claim 4, wherein the interior luminaire der Rukoto. A plurality of LEDs arranged in a straight line and the diffusion sheet according to any one of claims 1 to 3 , wherein a unit lens array on a surface on which the diffusion sheet is disposed on the LED arranged in a line L ED luminaire you characterized in that the arrangement direction of the ridge line direction and the LED is disposed curved to Cartesian. The LED lighting apparatus according to claim 6, wherein the LED lighting apparatus is a desk lamp .