JP2011119086A - Led illumination device - Google Patents

Abstract

To provide an LED lighting device that is bright and has excellent light distribution characteristics with little unevenness in brightness, and that can easily adjust the color temperature of illumination light.
An LED lighting device 100 includes at least a plurality of LED elements 1 and a light distribution lens sheet 2 disposed so as to face the LED elements 1, and the light distribution lens sheet 2 is a sheet surface on the illumination side of a sheet-like main body 23. 24, a large number of hemispherical unit lens elements 31 constituting the fly-eye lens 3 are arranged with a gap therebetween, and a columnar prism group 4 is formed on the sheet surface of the gap to form a convex column shape such as a triangular cross section. It is assumed that a plurality of unit prism elements 41 are arranged. Further, a color temperature changing layer may be provided. The fly-eye lens and the columnar prism group exhibit the light diffusing function and the condensing function to achieve the desired light distribution characteristics.
[Selection] Figure 1

Description

  The present invention relates to an LED lighting device using an LED (light emitting diode) as a light source.

  As compared with the conventional fluorescent lamp illumination device, replacement with an LED illumination device using a light emitting diode (LED) as a light source is progressing. This is because there is a problem at the time of disposal in terms of environmental friendliness because of the very small amount of mercury contained in fluorescent lamps, and a completely mercury-free lighting device can be realized by replacing it with an LED lighting device. is there. In addition, a fluorescent lamp requires a ballast and an inverter, but an LED lighting device does not require it, so power consumption can be reduced. On the other hand, incandescent bulbs do not have problems with mercury, inverters, etc., but have lower luminous efficiency and shorter lifetime than fluorescent lamps, so replacement with LED lighting devices can also reduce power consumption and extend lifetime. From such a background, various LED lighting devices have been proposed and put into practical use (Patent Document 1).

  In addition, fluorescent lamps have, for example, daylight color, daylight white, white, and bulb color depending on the color of the illumination light. Similarly, LED lighting devices also use daylight color, daylight white, white, bulb color, etc. Are commercially available. And in order to adjust a hue with an LED lighting apparatus, it carries out by LED element itself to be used. Furthermore, there has also been proposed a product in which a color adjustment filter is bonded and laminated on an LED element covered with a sealing resin to finely adjust the color after resin sealing (Patent Document 2). ).

JP 2008-21561 A JP 2009-1441066 A

However, in the LED lighting device, the directivity of the light emitted from the LED element as the light source is strong, so the front surface of the LED element is bright, but the surrounding area is dark. Moreover, even if a plurality of LED elements are arranged in the plane, this tendency remains, the area between the LED elements becomes dark, and if the LED elements are not arranged densely, uneven dot-like brightness (light source image) (Hot spot to light image)).
Therefore, in Patent Document 1, the light distribution characteristics are made uniform by, for example, providing a Fresnel lens made of a lens body concentrically for each LED element on the front surface of each of the plurality of LED elements arranged. However, although the Fresnel lens has the effect of condensing light in a certain direction, it cannot be expected to spread to the surroundings, and it is difficult to eliminate unevenness in the brightness of the illumination light.

In addition, the lighting device is required to have illumination light shades depending on the application, such as daylight color, day white color, and light bulb color, and the LED illumination device supports the LED element itself to be incorporated. It was difficult to set freely depending on the application regardless of the LED element to be incorporated.
Met.

  That is, the subject of this invention is providing the LED illuminating device from which the outstanding light distribution characteristic with few brightness nonuniformity is obtained. Moreover, this invention is making it possible to set easily the hue (color temperature) of illumination light in such an LED illuminating device.

The LED lighting device according to the present invention has the following configuration.
(1) A plurality of LED elements, and a sheet-like arrangement that has a large number of lens elements arranged opposite to the plurality of LED elements and allows light source light emitted from the LED elements to be incident on the light source side surface and transmitted to the illumination side surface. In the LED illumination device having at least a light lens sheet, the light distribution lens sheet is arranged on a sheet-like main body portion and a sheet surface on the illumination side of the main body portion, and a plurality of hemispheres constituting a fly-eye lens A plurality of columnar unit prism elements that are arranged on the sheet surface and constitute a columnar prism group, and the hemispherical unit lens elements are arranged with a gap on the sheet surface, The columnar unit prism element is disposed between the hemispherical unit lens elements on the sheet surface, and includes a normal line standing on the sheet surface and includes a columnar unit prism element. In cross-sectional shape in a cross section perpendicular to the direction in which the extending is convex, LED lighting device.
(2) In the above (1), the LED illuminating device in which the light diffusing member is further arranged in one or both of the space between the LED element and the light distribution lens sheet and the illumination side of the light distribution lens sheet. .
(3) In the above (1) or (2), the LED illumination further comprising a color temperature conversion layer for changing the color temperature of the light source light emitted from the LED element to produce illumination light having a different color temperature. apparatus.

(1) According to the present invention, when the light source light emitted from the LED element passes through the light distribution lens sheet and becomes illumination light, the light distribution lens sheet is not a prism sheet having a simple prism group, Since the prism group and the fly eye lens are provided in a predetermined arrangement on the illumination side sheet surface of the light distribution sheet, not the lens sheet having the fly eye lens, the light is diffused by the fly eye lens and the prism group The light is condensed, the brightness in the front direction is bright, and excellent light distribution characteristics with little unevenness of brightness in the front direction and its surroundings can be obtained. In other words, the light distribution function of moderate light diffusion and appropriate light collection can be set mainly by the light diffusion function by the fly-eye lens and the light collection function by the prism group, so the part illuminated at the front is bright and the surroundings Excellent light distribution characteristics with less uneven brightness.
In addition, since the light diffuses, when the LED lighting device is viewed, it is possible to prevent a certain portion of the LED elements arranged in a dot shape in a plane from appearing brighter in a dot shape than a portion without the LED element.
In addition, the compounded shape of the lens and prism of the light distribution lens sheet has the disadvantage that air remains in the concave portion of the mold and becomes a concave portion on the molded product when the concave and convex shape is molded. The shape can be stably produced without any problems, so that the optical function as expected can be exhibited.

(2) Further, by arranging the light diffusing member, the light diffusing function is enhanced, and the LED element portion can be more effectively prevented from appearing brighter in a dot-like manner than the surroundings, and uneven brightness is also achieved. Improve more.
(3) Furthermore, by providing a color temperature conversion layer, illumination light having a color temperature different from the color temperature of the light source light emitted from the LED element can be obtained, so that an LED element having a light emission color different from the required illumination color can also be used. . As a result, a cost-effective LED element can be used without being limited to its emission color.

Sectional drawing which illustrates notionally one form (direct light source type) of the LED lighting apparatus by this invention. The top view which illustrates one form of the light distribution lens sheet incorporated in a LED lighting apparatus. FIG. 3 is a cross-sectional view conceptually illustrating a hemispherical unit lens element and a columnar unit prism element of a light distribution lens sheet. Sectional drawing explaining notionally another form (side light source type) of the LED lighting apparatus by this invention. Sectional drawing which illustrates two examples as a form example of the structure also provided with the light-diffusion member. Sectional drawing which illustrates five examples as a form example of the structure also provided with the color temperature conversion layer. Sectional drawing which illustrates the form example of a structure also provided with the protection board.

    The present invention will be described below with reference to the drawings. Note that the drawings are conceptual diagrams, and the scale relationships, aspect ratios, and the like of components may be exaggerated.

<Summary>
First, the LED lighting device of the present invention includes a plurality of LED elements 1 and a light distribution lens sheet 2 disposed to face the plurality of LED elements 1 like the LED lighting device 100 in the form illustrated in FIG. At least. The light distribution lens sheet 2 has a sheet-like shape in which the light source light Ls emitted from the LED element 1 is incident on the light source side surface 21 and transmitted to the illumination side surface (light emission side surface) 22, and the illumination light Li is emitted from the illumination side surface 22. It is an optical member.
Moreover, in the present invention, the light distribution lens sheet 2 includes a sheet-like main body portion 23 and a plurality of the fly-eye lenses 3 that are arranged on the illumination-side (light-emitting side) sheet surface 24 of the main body portion 23. A hemispherical unit lens element 31 and a plurality of columnar unit prism elements 41 arranged on the sheet surface 24 and constituting the columnar prism group 4 are provided. Moreover, the hemispherical unit lens elements 31 are arranged with a gap on the illumination-side sheet surface 24 of the main body, and the columnar unit prism elements 41 are the hemispherical units on the sheet surface 24. The cross-sectional shape in the cross section that is disposed between the lens elements 31 and that is parallel to the normal direction to the sheet surface 24 and orthogonal to the direction in which the columnar unit prism elements 41 extend has a convex shape. . That is, the light distribution lens sheet 2 receives the light source light Ls radiated from the LED element 1 from the light incident side, and is appropriately adjusted by the compound lens composed of the fly-eye lens 3 and the columnar prism group 4 provided on the light output side. It is emitted as illumination light Li that has been diffused and condensed.
Note that when the sheet surface 24 is completely filled with these unit optical elements 31 and 41, the sheet surface is not exposed to the air and becomes a virtual internal surface.

In the present invention, an appropriate light collecting function and light diffusion can be achieved by using a light distribution lens sheet that is not a simple prism sheet or a simple fly-eye lens but also has a fly-eye lens and a prism group in a predetermined arrangement. Depending on the function, the light distribution characteristics can be improved, and the brightness and brightness unevenness can be improved.
Further, the arrangement surface of the plurality of LED elements 1 is not limited to “side light source type” or “facing light source type” which is directly below the light distribution lens sheet 2 as illustrated in FIG. A “light source type” or the like may be used (see FIG. 4). Further, in the “direct light source type” illustrated in FIG. 1, the arrangement surface of the LED element 1 is parallel to the sheet surface 24 of the light distribution lens sheet 2.
The “direct light source type” in FIG. 1 can also be said to be “direct light source type” if the drawing is turned upside down. Also, in FIG. 1, the illumination light Li travels upward in the drawing, and this direction and the direction in which the illumination light travels when the LED illumination device is actually used are, for example, upward, downward, lateral, etc. The direction of installation is arbitrary and irrelevant.

  Furthermore, in the LED lighting device of the present invention, the light diffusing member 5 is arranged to enhance the light diffusing function (see FIG. 5), or the color temperature conversion layer is used to make the color of the illuminating light as desired. 6 (see FIG. 6), or a protective plate 7 for protecting from scratches and dust (see FIG. 7).

As shown in FIG. 1, the plurality of LED elements 1 are usually installed and fixed on a base 8 (illustrated by a one-dot chain line). Of course, in addition to this, each LED element 1 is connected to a power source by an electric wire and applied with a voltage. Further, if necessary, an additional circuit for dimming is further provided. Furthermore, the LED lighting device is usually a switch (switch) for turning on / off the lighting, a frame (or box, casing, or housing) that houses the structure shown in the figure, a jig for mounting on the ceiling, etc. These are well-known matters and are not shown in the accompanying drawings for the sake of simplicity. The light distribution lens sheet 2 is disposed at a spatial position facing the plurality of LED elements 1. However, in the present invention, the relative spatial arrangement of the light distribution lens sheet 2 and the LED element 1 may be a side light source type (also referred to as a side light type) such as the LED lighting device 100 illustrated in FIG. In FIG. 4, the LED element 1 is disposed on a side surface of the light guide 9 such as a plate shape, and light emitted from the LED element 1 enters the light guide 9 from the side surface, and enters the light distribution lens sheet 2. Light source light Ls is emitted as a planar light source from the outgoing light exit surface. After that, the illumination light Li is obtained in the same manner as in the embodiment of FIG.
In the case of the side light source type, when a light guide 9 is provided with light diffusive printing dots on the back side in order to direct light incident from the side to the front light exit surface, a light distribution lens is used. Due to the light diffusion effect of the sheet 2, there is also an effect that it is possible to suppress the printing dots from appearing as a light and dark pattern in the form of dots.

In the present specification, the “illumination side” refers to the downstream in the light traveling direction when heading from the LED element 1 to the place to be illuminated through the light distribution lens sheet 2 or the like without folding the traveling direction. 1 (the illumination side is the upper side in FIG. 1 and FIGS. 3 to 7), and the “light source side” is illuminated from the LED element 1 through the light distribution lens sheet 2 and the like without folding the traveling direction. It is the upstream side in the light traveling direction when heading to the power point.
In addition, the “light exit side” is a side where light entering an object such as the light distribution lens sheet 2 exits from the countermeasure object, and is a downstream side in the traveling direction of the focused light. "Is a side where light enters an object such as a light distribution lens sheet, and is an upstream side in the traveling direction of the focused light.
The “sheet surface” of the main body 23 includes a “light source side” and an “illumination side”, and among these, the “illumination side” “sheet surface 24” is provided with the fly-eye lens 3 and the columnar prism group 4. Surface.

Further, in the present invention, the terms “sheet”, “film”, and “plate” are not distinguished from each other only based on the difference in names. Therefore, for example, a “sheet” is a concept including a member that can also be called a film or a plate.
Furthermore, in the present invention, the “sheet surface (film surface, plate surface)” is a surface that coincides with the planar direction of the target sheet-like member when the target sheet-like member is viewed as a whole and globally. (In the case of an uneven surface, it also corresponds to the envelope surface). However, the global is an envelope surface obtained by smoothing the surface unevenness by a fly-eye lens or a columnar prism. For example, in the case of a sheet surface curved into a two-dimensional curved surface with a radius of curvature of 1 m, this curve is used. It does not mean that the entire sheet surface is flattened from end to end and regarded as a plane.

Further, in the present invention, the “front direction” is the illumination side (or light emission side) along the normal line nd (see FIG. 3) with respect to the sheet surface of the light distribution lens sheet 2, and the normal line nd is Also, it is parallel to the normal to the virtual light-emitting surface formed by the LED elements 1 arranged in a plane.
Moreover, in the form example demonstrated by this invention, the light-incidence side of each of the arrangement | positioning surface of the LED element 1 arrange | positioned in multiple numbers, the sheet surface of the light distribution lens sheet 2, the light-diffusion member 5, the color temperature conversion layer 6, and the protection board 7 is shown. And the light outgoing side are parallel to each other. However, these are not necessarily all parallel and may be non-parallel.

<< Example Embodiment >>
Next, an embodiment of the LED lighting device of the present invention will be described with reference to FIGS.

(Light distribution lens sheet)
First, in the present embodiment, the multiple hemispherical unit lens elements 31 constituting the fly-eye lens 3 in the light distribution lens sheet 2 have a three-dimensional shape corresponding to a part of a spheroid, and are adjacent to each other. The pitch P1 between the two matching elements 31 is 40 μm, the circular diameter (width W1) of the bottom surface in contact with the sheet surface 24 is 30 μm, the average minimum distance Sa is 10 μm, and the protrusion height H1 is 15 μm. is there. The hemispherical unit lens elements 31 are arranged in an arrangement in which the respective elements are slightly separated from the arrangement in which the sheet surface 24 is closely packed on the sheet surface 24.
On the other hand, a large number of linear columnar unit prism elements 41 constituting the columnar prism 4 extending linearly in a plan view have a cross-sectional shape of a right-angled isosceles with a base of 10 μm in contact with the sheet surface 24 and a vertex angle of 90 °. On the basis of the triangular shape, the apex was chamfered and rounded with a radius of curvature of 4 μm. The columnar unit prism elements 41 are arranged on the sheet surface 24 in the gap between the hemispherical unit lens elements 31 with an arrangement pitch of 10 μm in a direction orthogonal to the direction in which the columnar unit prism elements 41 extend.
The light distribution lens sheet 2 can be manufactured using a cylindrical mold (mold roll), a liquid ionizing radiation curable resin, and a resin sheet of the manufacturing method a) described later. The fly-eye lens 3 and the columnar prism 4 are formed by solidifying an ionizing radiation curable resin that is cured by ultraviolet rays or an electron beam on the surface 24 of a transparent polyester resin sheet that is the main body 23 of the light distribution lens sheet 2. can do.

(LED lighting device)
In the present embodiment, the LED illumination device 100 includes a columnar unit prism on the illumination side in front of a number of white LED elements 1 in which the light distribution lens sheet 2 is two-dimensionally arranged in a square lattice pattern on a plane. The arrangement direction of the elements 41 is parallel to one arrangement direction da of the two-dimensionally arranged LED elements 1, and the linear columnar unit prism elements 41 are also parallel to the linearly extending direction.

  In this way, the brightness in the front direction is bright, the front direction is brightly illuminated with illumination light, and the surrounding light can be diffused and brightened, and when the LED illumination device is viewed, the portion where the LED element is disposed However, it is not brighter than other parts, and the light distribution performance that the LED image is not conspicuous is obtained.

On the other hand, if the light distribution lens sheet is an LED illuminating device in which the columnar prism 4 is not provided and instead only the fly-eye lens 3 in which the hemispherical unit lens elements 31 are closely packed, the illumination light becomes dark. Therefore, the light distribution performance as described above cannot be obtained.
Further, the light distribution lens sheet is not provided with the fly-eye lens 3 with respect to the light distribution lens sheet, but instead is only the columnar prism 4 in which the entire sheet surface is filled with a large number of linear columnar unit prism elements 41. When the LED illumination device is used, an LED image is visible. This phenomenon is the same even when the right-angled isosceles triangular shape of the cross-sectional shape of the columnar unit prism element 41 is arranged with a height of 24 μm and a base of 50 μm without a gap, and the light distribution performance as described above cannot be obtained. .

  Hereinafter, the present invention will be further described in detail for each member.

<< LED element >>
There is no limitation in particular as the LED element 1, What is necessary is just to use an appropriate thing in consideration of luminescent color, cost, etc. For example, as a LED element, a white LED element, a blue LED element, a green LED element, a yellow-green LED element, an orange LED element, a red LED element, a purple LED element, an ultraviolet LED element, etc. are appropriately adopted. Can do.
In general, a single LED element 1 is used because the amount of light is small. When a plurality of LED elements 1 are used, in order to arrange each LED element 1 at a desired position, the mutual positional relationship is fixed using the substrate 8 as shown in FIG. The substrate 8 is not particularly limited, such as a printed board, metal, glass, ceramics, resin, or the like.
Further, when the LED elements 1 are arranged, the arrangement along the arrangement surface is arbitrary, for example, a square lattice shape, a hexagonal lattice shape, a linear shape, a polygonal line shape, a curved shape, a concentric circle shape, a radial shape, and the like. Also, it may be regular or irregular.

《Light distribution lens sheet》
The light distribution lens sheet 2 is a transparent optical sheet having a fly-eye lens 3 and a columnar prism group 4 on the illumination side (light output side). Moreover, the optical sheet is a transparent optical sheet in which a plurality of columnar unit prism elements 41 constituting the columnar unit prism group 4 are arranged in a gap between the plurality of hemispherical unit lens elements 31 constituting the fly-eye lens 3. More specifically, as shown in FIGS. 1 and 2, the plurality of hemispherical unit lens elements 31 are two-dimensionally arranged on the sheet surface 24 on the illumination side of the sheet-like main body 23, and a plurality of columnar unit prisms. The element 41 is disposed in the gap between the hemispherical unit lens elements 31 on the sheet surface 24.
Further, the light incident side surface 21 (also the light source side surface of the main body 23) of the light distribution lens sheet 2 may be a smooth surface that is not a lens surface or a prism surface. In addition, it is good also as a structure etc. which provided the light-diffusion function by making this surface into a mat | matte surface, and laminated | stacked the light-diffusion member.

[Hemispherical unit lens element]
The hemispherical unit lens element 31 is a lens element that constitutes the fly-eye lens 3 by a large number of hemispherical unit lens elements 31. The fly-eye lens 3 is also called a fly-eye lens, and is a plurality of unit lenses arranged at regular intervals or irregular (random) intervals in two different directions on a plane. It means a lens composed of elements.

(Cross section and bottom shape)
The (longitudinal) cross-sectional shape in the cross section of the hemispherical unit lens element 31 (that is, the plane including the normal nd standing on the illumination-side sheet surface 24 of the sheet-like main body 23) is a cross-section protruding to the light output side. It has a shape, for example, a cross-sectional shape corresponding to a part of a circle or a part of an ellipse (in a solid shape, a part of a sphere or a spheroid). When the cross-sectional shape corresponds to a part of an ellipse, from the viewpoint of intensively improving the brightness of the front, either the long axis or the short axis of the cross-sectional elliptical shape is the light distribution lens sheet 2. It is preferable to be parallel to the normal direction nd (that is, the front direction) standing on the sheet surface.
Further, the (planar) shape of the bottom surface (surface connected to the main body portion 23) of the hemispherical unit lens element 31, that is, the shape corresponding to the projection onto the sheet surface 24 of the hemispherical unit lens element 31, is circular or elliptical. Etc.

In addition to the above, the cross-sectional shape may be, for example, hyperbola, parabola, cycloid, cardioid, normal distribution curve, sine curve, hyperbolic sine curve, elliptic function curve (sn function, cn function, etc.), Bessel function curve, Or it is good also as a shape corresponded to a part of Rankine's egg shape.
In addition to the above, the shape of the bottom surface of the hemispherical unit lens element 31 may be a polygonal shape such as a triangle, a quadrangle, a pentagon, a hexagon, and an octagon.
These cross-sectional shapes and bottom surface shapes may be appropriately selected according to the required optical functions (condensing function, light diffusion function, aberration, retroreflectivity, etc.).
Further, the shape and size of the individual hemispherical unit lens elements 31 arranged in a plurality are usually the same shape and size, but in addition to this, at least one of a cross-sectional shape, a bottom surface shape, etc. is different from each other. The fly-eye lens 3 may be composed of a kind of hemispherical unit lens element 31.

(Plane arrangement)
The arrangement of the plurality of hemispherical unit lens elements 31 in the sheet surface 24 on the illumination side of the sheet-like main body portion 23 includes columnar unit prism elements 41 at least between the hemispherical unit lens elements 31. It is set as the arrangement | sequence which has the space | interval which can be provided. The (total) width of the gap in the entire sheet surface 24 depends on the ratio of optical functions (such as a light collecting function and a light diffusing function) shared by the hemispherical unit lens element 31 and the columnar unit prism element 41. It is good to set.
The geometric shape of the arrangement of the plurality of hemispherical unit lens elements 31 in the sheet surface 24 is basically not particularly limited as long as it has the gaps as described above. Typically, for example, as illustrated in the plan view of FIG. 2, an array in which a predetermined gap is secured by slightly separating each circle from an array in which the bottom surface is circularly packed in a close-packed manner. That is, one hemispherical unit lens element 31 is surrounded from the periphery by six hemispherical unit lens elements 31 that are arranged symmetrically six times circumferentially at equal intervals. This corresponds to an arrangement in which the unit shape elements are slightly separated from the so-called hexagonal close-packed structure in the crystal. In other words, a large number of hemispherical unit lens elements 31 are common in two different directions (the first direction d1 and the second direction d2 in FIG. 2) inclined at an angle of 60 ° on the sheet surface 24. Arranged at a pitch.
In this way, when the arrangement of the plurality of hemispherical unit lens elements 31 arranged in the sheet surface 24 is circularly symmetric and isotropic, an arbitrary one on the sheet surface of the light distribution lens sheet 2 is used. In the vertical plane along the direction (surface including the normal line nd), the traveling direction of the light emitted from the light distribution lens sheet 2 can be similarly changed. That is, the light distribution function mainly including the light diffusion function by the fly-eye lens 3 of the light distribution lens sheet 2 can be exhibited without considering the arrangement of the plurality of LED elements 1 and the like.

(Specific examples of arrangement and dimensions)
If the specific example of arrangement | positioning and a dimension of the hemispherical unit lens element 31 is given, the arrangement | sequence pitch P1 (refer FIG. 2) of the hemispherical unit lens element 31 on the sheet | seat surface 24 of the main-body part 23 can be 11-400 micrometers. . Further, the width W1 (see FIG. 2) of the bottom surface of the hemispherical unit lens element 31 along the arrangement direction of the hemispherical unit lens elements 31 on the sheet surface 24 can be set to 10 to 200 μm. Furthermore, the protrusion height H1 (see FIG. 3) of the light distribution lens sheet 2 from the illumination-side sheet surface 24 in the cross-sectional shape of the hemispherical unit lens element 31 can be set to 5 to 100 μm. In each of the illustrated drawings, a large number of hemispherical unit lens elements 31 have the same shape and size.

[Columnar unit prism element]
The columnar unit prism element 41 is a prism element that constitutes the columnar prism group 4 by a large number of columnar unit prism elements 41. The direction in which the columnar unit prism element 41 extends, that is, the direction in which the prism ridge extends, is typically linear as in the columnar unit prism element 41 illustrated in the plan view of FIG. It extends in a straight line in the horizontal direction). Further, the extending direction may be a curved line such as a circle or a wave shape, a broken line, or the like other than a straight line. A circular shape corresponds to a so-called Fresnel lens, and a straight line corresponds to a linear Fresnel lens.
Whether the extending direction is a straight line or a curved line, when viewed locally, the direction in the sheet plane orthogonal to the extending direction is the arrangement direction of the columnar unit prism elements 41.

(Cross section and bottom shape)
A cross section of the columnar unit prism element 41 (that is, includes a normal line nd standing on the illumination-side sheet surface 24 of the sheet-shaped main body 23 and is orthogonal to a direction in which the columnar unit prism element 41 (ridge or ridge line) extends. The (longitudinal) cross-sectional shape in (surface) is a cross-sectional shape protruding toward the light output side, for example, a triangular shape with the bottom surface facing the sheet surface 24. From the viewpoint of increasing the illumination light traveling in the front direction, the cross-sectional shape is preferably a triangular shape such as an isosceles triangular shape. In addition to this, the cross-sectional shape may be a shape obtained by modifying a triangular shape in order to adjust the light distribution characteristics. For example, there are a shape in which one or more hypotenuses are bent, a shape in which one or more hypotenuses are curved, a shape in which the vicinity of the apex is curved and rounded, other shapes, or a combination thereof.

These cross-sectional shapes may be appropriately selected according to the required optical functions (condensing function, light diffusion function, aberration, retroreflectivity, etc.).
In addition, the shape and size of the individual columnar unit prism elements 41 arranged in a plurality are usually all the same shape and size, but in addition to this, a plurality of types of columnar units having at least one cross-sectional shape or the like different from each other. The prism element 41 may constitute the columnar prism group 4.

(Specific examples of arrangement and dimensions)
If the specific example of arrangement | positioning and dimension of the columnar unit prism element 41 is given, the columnar unit prism element 41 along the arrangement direction of the columnar unit prism element 41 on the illumination-side sheet surface 24 of the sheet-like main body 23 will be described. The bottom width W2 (see FIG. 2) can be set to 1 to 200 μm. Further, the protrusion height H2 (see FIG. 3) of the light distribution lens sheet 2 from the illumination-side sheet surface 24 in the cross-sectional shape of the columnar unit prism element 41 can be set to 0.5 to 50 μm. In each of the illustrated drawings, the multiple columnar unit prism elements 41 have the same shape and size.
Further, when the cross-sectional shape of the columnar unit prism element 41 is an isosceles triangle with a rounded vertex, from the viewpoint of increasing the luminance in the front direction and intensively increasing the illumination light toward the front direction. The apex angle θ of the hypothetical vertex that is located between the equal sides and protrudes toward the light-emitting side and that is before the shape deformation and intersects both oblique sides is preferably 80 to 120 °, 90 ° Is more preferable.
Note that the roundness in the case of providing roundness is not less than the maximum wavelength (781 nm) of visible light in terms of the radius of curvature.

[Light distribution of hemispherical unit lens element and columnar unit prism element]
Next, the light distribution action of the hemispherical unit lens element and the columnar unit prism element will be described with reference to FIGS. In the light distribution lens sheet 2 illustrated in these drawings, the hemispherical unit lens element 31 has a circular or elliptical cross-sectional shape, and the columnar unit prism element 41 has a triangular or substantially triangular cross-sectional shape.
First, if the traveling direction of light incident on the columnar unit prism element 41 having a triangular cross-sectional shape has a constant inclination angle with respect to the normal nd, the slope of the columnar unit prism element 41 is a flat surface, and the slope is obtained anywhere on the slope. In order to form a certain angle with respect to the line nd, the inclination of the light emitted from the columnar unit prism element 41 with respect to the normal nd regardless of the position on the inclined surface where the light is incident (struck) The angle is also constant. That is, the traveling direction of the light emitted from the columnar unit prism element 41 is generally determined by the configuration (for example, shape, refractive index, etc.) of the columnar unit prism element 41.
On the other hand, the light incident on the hemispherical unit lens element 31 whose cross-sectional shape is a part of a circle or an ellipse has a constant inclination angle with respect to the normal nd in the traveling direction of the light, even if the inclination angle of the hemispherical unit lens element 31 is constant. The inclination angle of the outgoing light from the hemispherical unit lens element 31 with respect to the normal nd of the outgoing direction varies depending on the position on the outgoing light side surface (lens surface). That is, the traveling direction of the light emitted from the hemispherical unit lens element 31 is not only the configuration of the hemispherical unit lens element 55 (for example, the shape and refractive index) but also the incident position on the hemispherical unit lens element 55. Is also greatly affected.

The arrangement interval of the hemispherical unit lens elements 31 and the arrangement interval of the columnar unit prism elements 41 are very narrow compared to the arrangement interval of the LED elements 1. Therefore, the inclination angles of the light incident from the LED element 1 toward the single hemispherical unit lens element 31 and the columnar unit prism element 41 are substantially the same.
As a result, the columnar unit prism element 41 can narrow the traveling direction of the emitted light within a relatively narrow angle range centered on the normal line nd. That is, the columnar unit prism element 41 can exhibit an extremely excellent light collecting function by appropriately designing its configuration.

On the other hand, the hemispherical unit lens element 31 narrows the angle of inclination with respect to the normal nd within a relatively wide angle range with respect to the traveling direction of the emitted light, and smoothly changes the luminance distribution within the narrowed angle range. You can That is, the columnar unit prism element 41 can exhibit a stronger light collecting function than the hemispherical unit lens element 31, and the hemispherical unit lens element 31 has a stronger light than the columnar unit prism element 41. The diffusion function can be demonstrated.
Then, the configurations of the hemispherical unit lens element 31 and the columnar unit prism element 41 are appropriately designed, and the formation area of the hemispherical unit lens element 31 and the columnar unit prism element 41 are formed on the sheet surface 24 of the main body 23. Desired light distribution characteristics can be imparted to the light distribution lens sheet 2 by appropriately adjusting the formation region.

  By providing both the hemispherical unit lens element 31 and the columnar unit prism element 41, the light transmitted through the light distribution lens sheet 2 is condensed to effectively increase the light in the front direction, thereby increasing the luminance in the front direction. While increasing effectively, it can also be diffused moderately and light is distributed also to the circumference | surroundings of a front direction, and the angle distribution with respect to the normal line nd of a brightness | luminance can also be changed smoothly. Further, unevenness (light source image) in which the arranged LED element 1 portion appears brighter than the other portions can be suppressed.

[Relative relationship between hemispherical unit lens element and columnar unit prism element]
Next, the relative relationship between the hemispherical unit lens element 31 and the columnar unit prism element 41 in terms of size, shape, function to be provided, and the like will be described.

(Plane arrangement)
By adjusting the distance between the two adjacent hemispherical unit lens elements 31 (average minimum distance Sa) and the arrangement pitch P2 of the columnar unit prism elements 41, the amount of light toward the normal nd direction is improved. It is possible to simultaneously suppress the in-plane variation in the amount of illumination light emitted from the light distribution lens sheet (conceal the phenomenon in which the LED element portion appears bright). Note that the average minimum distance Sa (see FIG. 2) is on the sheet surface 24 between another arbitrary hemispherical unit lens element 31 closest to any one hemispherical unit lens element 31. Is the average value of the separation intervals. The average minimum interval Sa is preferably set to an arrangement pitch P2 or more along the arrangement direction of the linearly extending columnar unit prism elements 41, and preferably two or more times the arrangement pitch P2. Since the light distribution function by the element 31 is lowered, it is preferably 10 times or less of the arrangement pitch P2.
Further, when the sheet surface 24 is filled with the hemispherical unit lens element 31 and the columnar unit prism element 41 without any gap, it is possible to prevent light from passing through the gap without contributing to the light distribution action of these optical elements. Is preferable. However, the gap may be provided as long as it does not depart from the gist of the present invention.

(Projection height H1 of the hemispherical unit lens element and projection height H2 of the columnar unit prism element)
The protrusion height H2 of the columnar unit prism element 41 is preferably lower than the protrusion height H1 of the hemispherical unit lens element 31 (see FIGS. 1 and 3). More specifically, the protrusion height H2 is preferably 1/10 to 9/10 of the protrusion height H1 of the hemispherical unit lens element 31. When the top of the columnar unit prism element 41 comes into contact with another member, the top is easily scraped off, but if the protruding height H2 of the columnar unit prism element 41 is lower than the protruding height H1 of the hemispherical unit lens element 31, This can be avoided. In addition, a phenomenon in which the luminance gradually decreases as the angle from the front direction is inclined with respect to the front direction luminance of the illumination light traveling in the front direction and then increases again near the horizontal with respect to the sheet surface (angle distribution of emitted light luminance ( Side lobe) in light distribution characteristics) can be suppressed.

[Positional relationship with LED element]
In the direction along the sheet surface 24 of the light distribution lens sheet 2, the planar arrangement of the LED elements 1 and the arrangement of the hemispherical unit lens elements 31 and the columnar unit prism elements 41 in the light distribution lens sheet 2 are: There is no particular limitation. What is necessary is just to set suitably so that the desired light distribution characteristic may be acquired. For example, in the form illustrated in FIG. 2, when the LED elements 1 are two-dimensionally arranged in a square lattice shape, one da in the arrangement direction is parallel to one d1 in the arrangement direction of the hemispherical unit lens elements 31. In addition, the linear columnar unit prism element 41 is also parallel to the linearly extending direction.

<< Example of manufacturing method of light distribution lens sheet >>
The light distribution lens sheet 2 can be manufactured using a known material by a known molding method, for example, the following method using a mold.
a) After the liquid ionizing radiation curable resin is applied to the mold surface of the cylindrical mold (mold roll), the resin sheet is pressed on the coated surface, and then the resin is cured on the mold surface. A molding method in which the sheet is peeled off and molded onto the curable resin surface;
b) A melt extrusion molding method in which a molten resin extruded from a T die or the like is supplied between a cylindrical mold (roll mold) and a press roll, and then molded.
c) injection molding method,
d) a hot press method in which a resin is sandwiched between a heated mold and a metal plate or metal roll, and heated and pressurized;
e) A transfer method in which after the resin is laminated on the mold, the mold is peeled off and the shape of the mold surface is transferred to the resin surface.

In addition, it is more advantageous in terms of productivity and cost to use a cylindrical mold (mold roll) than a sheet mold or an injection mold. There is also an advantage that it can be stably produced without occurrence and can exhibit the expected optical function.
That is, a concave portion corresponding to the hemispherical unit lens element 31 and a groove corresponding to the columnar unit prism element 41 are formed on the mold surface of the mold (die roll). The shape of the columnar prism 4 and the molding die may be such that they extend in parallel to the circumferential direction, or extend in a spiral manner obliquely with respect to the circumferential direction of the mold surface. The recess is formed at a desired position on the mold surface by, for example, etching using photolithography technology, and then the groove is formed on the mold surface on which the recess has been formed, for example, by cutting using a cutting tool. It can be formed across the recess.
The resin sheet may be a transparent resin sheet such as a polyester resin such as polyethylene terephthalate, an acrylic resin, a polycarbonate resin, or an olefin resin. The ionizing radiation curable resin may be an acrylate-based resin that is cured by ultraviolet rays or electron beams.

In this way, if the groove is formed so as to extend in the circumferential direction of the mold surface, the resin material supplied to the mold surface of the rotating mold is easily filled in the groove. In addition, since the resin material is supplied along the groove, when the resin material is filled in the concave portion forming the hemispherical unit lens element 31, the gas existing in the concave portion is a groove connected to the concave portion. Therefore, it is possible to effectively prevent bubbles from remaining in the recess and forming a recess on the surface of the hemispherical unit lens element 31.
In order to maximize this effect, the shape of the groove extending in the circumferential direction and the shape of the columnar unit prism element 41 in plan view are the shape in plan view, and the shape in plan view is, for example, linear It is the shape extended to.
In order to promote the discharge of the gas from the mold, the protrusion height H2 of the columnar unit prism element 41 may be set to 1/10 or more of the protrusion height H1 of the hemispherical unit lens element 31. It has been found to be effective.

《Light diffusion member》
By further providing the light diffusing member 5, the light diffusing action can be enhanced when the light diffusing function of the light distribution lens sheet 2 is insufficient. Therefore, a wider area can be illuminated. Also, the LED image can be made less noticeable. The position where the light diffusing member 5 is provided is a position {FIG. 5 (a)} that is separated from the light distribution lens sheet 2 on the illumination side of the light distribution lens sheet 2 as in the LED illumination device 100 illustrated in FIG. Between the element 1 and the light distribution lens sheet 2, any of {FIG. 5 (b)} may be used. In the former form of FIG. 5A, the uneven surface of the illumination side surface 22 (light emission side surface) by the fly-eye lens 3 and the columnar prism 4 provided on the illumination side of the light distribution lens sheet 2 by the light diffusion member 5. Can also be protected from dust and scratches. 5B is the case where the light diffusing member 5 is located away from the light distribution lens sheet 2, it may be disposed in close contact.
In addition, as the light diffusing member 5, for example, a layer in which a known light diffusing material is dispersed in a resin layer is used as a resin sheet itself, a layer in which a layer in which a light diffusing material is dispersed is laminated on a resin sheet, Alternatively, the surface of the resin sheet may be an uneven surface by embossing or hairline processing.

<Color temperature conversion layer>
By further providing the color temperature conversion layer 6 (see FIG. 6), the illumination light radiated from the LED lighting device 100 can be changed to a desired color irrespective of the color of the light source light of the incorporated LED element 1. . Accordingly, when the illumination light is, for example, daylight color, daylight white, white, light bulb color, etc., the light source light of the built-in LED element does not have to be the same daylight color, day white color, white, light bulb color, etc. as the illumination light. Therefore, the LED element can be selected in consideration of cost and the like.
Incidentally, in JIS, the light source color of a fluorescent lamp is defined by “color name” (daylight color, daylight white, white, temperature white, light bulb color). These color names are 5700 in this order in terms of color temperature. -7100K, 4600-5500K, 3800-4500K, 3250-3800K, 2600-3250K (JIS Z9112: 2004). In general, the daylight color is said to be about 6700K, the day white is about 5000K, the white is about 4200K, the warm white is about 3500K, and the light bulb color is about 3000K. And the layer which converts the color temperature of the color of the light source light which LED element 1 radiates into the color temperature of the color of the illumination light finally requested | required is a color temperature conversion layer.
Note that the color conversion by the color temperature conversion layer is not limited to the “color name” of the fluorescent lamp specified by JIS, but it also means conversion to an arbitrary hue.

The color temperature conversion layer 6 is not particularly limited. For example,
a) a layer that emits another color with respect to the emission color of the LED element;
b) a layer that emits a complementary color (as another color) with respect to the emission color of the LED element;
c) a layer in which the LED element emits ultraviolet light and emits visible light with respect to the ultraviolet light;
d) A layer that absorbs an unnecessary portion of the wavelength band of visible light in its emission spectrum and transmits the rest of the emission color of the LED element,
Etc. These may be combined.

The color temperature conversion layers a) to c) may contain a phosphor that emits visible light using the light source light of the LED element 1 as excitation light, and the color temperature of d) above. The conversion layer may contain a pigment that absorbs (part of) visible light from the light source light of the LED element 1 in the color temperature conversion layer.
More specifically, as a), a blue LED element that emits blue light is used as the LED element 1, and one or more colors such as red, yellow, green, and blue are emitted with respect to the blue light. Therefore, it is a layer containing one or more phosphors. For example, one or more colors such as red, yellow, green, and blue are emitted to whiten, and at this time, if three kinds of phosphors each emitting RGB red, green, and blue are used, The white color obtained is a three-wavelength type and has good color rendering properties.
The b) is a layer that uses a blue LED element that emits blue light as the LED element 1 and contains one or more phosphors for the blue light and emits a complementary color by the phosphors. Thereby, a part of the blue light of the LED element is transmitted and the remaining part is absorbed, and the blue light emitted from the phosphor and the complementary yellow color are mixed to whiten the illumination light.
As c), an ultraviolet LED element is used as the LED element 1, and one or more phosphors that emit visible light are used for the ultraviolet rays to form a layer that emits white light. Also here, for example, one or more colors such as red, yellow, green, and blue are emitted to whiten, etc., and three types of phosphors that emit three colors of red, green, and blue are used, and white is used. If so, the color rendering is also improved.
The above d) is a layer containing a pigment that emits yellow-green light and absorbs an unnecessary wavelength band (yellow) of the yellow-green light wavelength band and transmits green light. Thereby, green is used for illumination light. In other words, increasing the purity of green and obtaining green light with high saturation.

  Note that phosphors, pigments, and the like used for the color temperature conversion layer may be appropriately selected from known ones. For example, nitride phosphors, oxide phosphors, and more specifically, YAG (yttrium / aluminum / garnet) phosphors, α sun alloy phosphors, β sun alloy phosphors, cousin phosphors, etc. is there. At that time, in the case of receiving ultraviolet rays or sunlight, such as when used outdoors, it is preferable to use those having good weather resistance (light). For example, the dye is a weather-resistant (light) dye such as phthalocyanine blue, quinactridon red, or isoindolinone yellow.

The color temperature conversion layer 6 is provided as a layer in which such a phosphor or pigment is contained and dispersed in a transparent material. The transparent material is a transparent resin, or a transparent inorganic material such as glass or ceramics. Moreover, you may use an adhesive for a transparent material, and may make an adhesive layer serve as a color temperature conversion layer.
Further, the position where the color temperature conversion layer 6 is provided is not particularly limited, and for example, there is a form as illustrated in FIG. In FIG. 6, the position where the color temperature conversion layer 6 is provided is a position away from the illumination side of the light distribution lens sheet 2 in FIG. 6A, and between the LED element 1 and the light distribution lens sheet 2 in FIG. 6B. Illuminating light in contact with the sheet surface in the main body part 23 of the light distribution lens sheet 2 in FIG. 6E, the light source side in contact with the light source side surface in the main body portion 23 of the light distribution lens sheet 2. In FIG.
6A and 6B are independent layer forms in which the light distribution lens sheet 2 and the color temperature conversion layer 6 are separated, and FIGS. 6C to 6E are light distribution lenses. It is a composite form in which the sheet 2 and the color temperature conversion layer 6 are combined.
In the case where the above-described light diffusion member 5 is also provided, the color temperature conversion layer 6 is formed between the light diffusion member 5 and the light distribution lens sheet 2 in the form of FIG. It may be provided in contact with the side surface of the light source, may be provided on the illumination side of the light diffusing member 5 in an independent layer form or a composite form, or may be used as a color temperature conversion layer with the entire thickness of the light diffusing member. .

In the above composite form, the color temperature conversion layer is formed from a resin composition such as a resin solution containing a phosphor or a dye by a known film forming method such as a coating method or a printing method, and the main body of the light distribution lens sheet 2. It can be formed by forming on the front surface or the back surface of the portion 23, or by laminating a resin sheet or a resin plate containing a phosphor or a pigment.
In addition, in the separate independent layer form, an inorganic plate such as a resin sheet or a resin plate containing a phosphor or a pigment, or a glass plate may be used.

  In addition, the LED element 1 itself may be made white by mixing the original blue color by providing a phosphor-containing layer in a light emitting part that emits blue light, for example, in order to obtain a white LED element, and causing the phosphor to emit yellow light. Has been done. In the present invention, the original light emission color is used as it is for the LED light emitting element 1 in which the light emission color is adjusted by using the phosphor together with the LED light emitting element itself, or without using the phosphor or the dye. It is also effective for the LED element 1 used as a color. This is because it is possible to finely adjust the color temperature with respect to the former using illumination device members other than the LED elements.

<Other components>
In addition to the above-described layers / members, the LED lighting device 100 may be provided with other layers / members within a range not departing from the gist of the present invention. For example, a protective plate, an antireflection layer, a reflection member, an antistatic layer, an antifouling layer, and the like. Hereinafter, the protective plate, the antireflection layer, and the antistatic layer will be described. The reflection member is provided on the back side of the LED element 1 other than the illumination side, and directs the light that reaches the light distribution lens sheet side to become illumination light. The layer prevents contamination due to dust adhesion.

[Protective plate]
The protection plate 7 is configured such that the constituent members located on the most illumination side of the LED illumination device 100 and disposed on the light source side of the protection plate 7 are dusted, scratched, or dirty like the LED illumination device 100 illustrated in FIG. It is a member which protects from etc. For the protective plate 7, a known transparent member, for example, a resin plate, a glass plate, a ceramic plate, or the like can be used. The protective plate may also be used as the light diffusing member.

[Antireflection layer]
The antireflection layer is a layer that is provided on the surface of a member in contact with air to prevent surface reflection. Specific examples of the surface include the light source side surface 21 on which neither the lens nor the prism of the light distribution lens sheet 2 is formed, the light source side surface or the illumination side surface of the light diffusion member 5 or the protection plate 7. A well-known thing can be employ | adopted suitably as an antireflection layer. For example, a single-layer antireflection layer composed of a low refractive index layer, a multilayer antireflection layer in which a low refractive index layer and a high refractive index layer are alternately laminated with the low refractive index layer as the outermost surface layer, or a moth-eye structure. .

  As the low refractive index layer, an inorganic material such as a fluoride such as silicon oxide or magnesium, or an organic material such as a silicon-based organic compound (for example, silicone) or a fluorine-based organic compound (for example, a fluorine-based resin) is used. Hollow fine particles (for example, silicon oxide) are also used. On the other hand, as the high refractive index layer, inorganic materials such as titanium oxide, indium tin oxide, and cerium oxide, and organic materials (resins) such as polyester resins and styrene resins are used. In the case of inorganic materials, these low refractive index layers and high refractive index layers can be formed by coating or printing a coating liquid in which an inorganic material is dispersed in a resin binder in addition to a vapor phase method such as vacuum deposition or sputtering. It can be formed by a wet method. Further, in the case of an organic material, a coating liquid using a resin binder as appropriate for the organic material can be formed by a wet method such as coating or printing.

  In the moth-eye structure, a large number of protrusions are arranged at an average pitch below the shortest wavelength of visible light in a vacuum on the antireflection surface to be antireflection, and each protrusion is an antireflection surface toward the air side. This is an antireflection structure comprising an uneven surface that protrudes so that the cross-sectional area in a plane parallel to the surface decreases. This uneven surface brings about a continuous refractive index change in the protruding direction of the protrusion, that is, the normal direction of the antireflection surface. For this reason, the light reflection phenomenon caused by the discontinuous and rapid refractive index change at the material interface does not occur. That is, this uneven surface does not function as an optical rough surface with respect to visible light and does not exert an optical effect on visible light. Such a moth-eye structure composed of an uneven surface is known, for example, from Japanese Patent Application Laid-Open No. 50-70040 and Japanese Patent No. 4197100.

[Antistatic layer]
The antistatic layer is a layer that prevents the light distribution lens sheet 2 from being charged and prevents dust from adhering to the light distribution lens sheet due to static electricity. The antistatic layer can be provided on the surface of the layer or inside the layer, and a known layer can be appropriately employed as long as it is transparent. Specific examples of such an antistatic layer include surfactants such as quaternary ammonium salts, transparent conductive metal oxides such as ITO (indium tin oxide) and ATO (antimony tin oxide), polythiophene, and the like. A conductive resin such as is used. In the case of using a surfactant or a conductive resin, the antistatic layer is formed by applying a liquid composition (coating liquid, etc.) in which these are appropriately dispersed or dissolved using a resin binder, and a base material such as a main body. Can be formed on top. Moreover, when using a transparent conductive metal oxide, it can form on base materials, such as a main-body part, by vapor phase methods, such as vacuum evaporation, a sputtering, plasma CVD, and ion plating. Or the particle | grains which atomized the transparent conductive metal oxide can be formed on base materials, such as a main-body part, by the coating method of the liquid composition (coating liquid etc.) disperse | distributed in the resin binder. For each resin binder, a thermoplastic resin, a thermosetting resin, an ionizing radiation curable resin, or the like is used.

<Application>
The application of the LED illumination device of the present invention is not particularly limited, and can be used for various illumination applications. For example, indoor lighting (ceilings, walls, floors, stairs, etc.) and outdoor lighting (entrance lighting, gate lights, etc.), indicator lights (displaying information on emergency exits, non-smoking, etc.), signs, street lights, security lights , Vehicle interior lighting, lighting advertising, luminous signboards and so on. Also, in places where the installation of the lighting device is difficult, such as high places, maintenance can be facilitated by taking advantage of the long life of the LED elements.

1 LED element 2 Light distribution lens sheet 21 Light source side surface (light incident side surface)
22 Illumination side (light emission side)
23 Main body 24 Sheet surface 3 Fly eye lens 31 Hemispherical unit lens element 4 Prism group 41 Columnar unit prism element 5 Light diffusing member 6 Color temperature conversion layer 7 Protective plate 8 Substrate 9 Light guide 100 LED lighting device

Claims (3)

A sheet-like light distribution lens sheet that has a plurality of LED elements and a plurality of lens elements that are arranged to face the plurality of LED elements and that allows light source light emitted from the LED elements to be incident on the light source side surface and transmitted to the illumination side surface. In an LED lighting device having at least
The light distribution lens sheet is arranged on a sheet-like main body, a plurality of hemispherical unit lens elements constituting a fly-eye lens arranged on a sheet surface on the illumination side of the main body, and the sheet surface. A plurality of columnar unit prism elements constituting a columnar prism group, and
The hemispherical unit lens elements are arranged with a gap on the sheet surface,
The columnar unit prism element is disposed between the hemispherical unit lens elements on the sheet surface, and includes a normal line standing on the sheet surface and is orthogonal to a direction in which the columnar unit prism element extends. The LED lighting apparatus whose cross-sectional shape in a cross section is convex shape.   The LED illuminating device of Claim 1 which has arrange | positioned the light-diffusion member in any one or both between the LED element and the light distribution lens sheet, and the space by the side of the illumination of a light distribution lens sheet. The LED lighting device according to claim 1, further comprising a color temperature conversion layer that changes the color temperature of the light source light emitted from the LED element to produce illumination light having a different color temperature.

Images