JP2015159075A - Led lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED lighting device capable of reducing light toward obliquely upward when directing light emission of an LED light source having strong directivity into an upper direction to a lateral side by utilizing reflection and refraction of a lens.SOLUTION: In an LED lighting device 10, a lens 11 comprises: a cylindrical surface-shaped side surface 12; an LED light source accommodation part 14; and a reflection surface 13. In the LED light source accommodation part 14, an upper part becomes an upper part incident surface 15, a side part becomes a side part incident surface 16, and an upper end of the side part incident surface 16 is inclined toward the side surface 12 of the lens 11. The side part incident surface 16 is formed close to the LED light source 20, so that, out of light emission of the LED light source 20, a lot of rays which cannot reach the reflection surface 13 enter the side part incident surface 16, and refract toward the lateral side on the inclined surface of the side part incident surface 16.

Description

  The present invention relates to an LED lighting device that covers a LED light source with a lens and radiates light emitted upward from the LED light source to the side.

  An LED light source in which an LED die is covered with a sealing resin or the like has directivity in light emission distribution and emits light strongly upward. An LED illumination device that emits light laterally using a reflector or a lens is known for light emission of such an LED light source. The method using a reflector has a problem that the reflector becomes large when a large amount of light is directed to the side. On the other hand, in the method of covering the LED light source with a lens, light can be directed to the side using refraction, so that the LED illumination device can be miniaturized.

  As an example of an LED illumination device in which a lens is placed on an LED light source, FIG. 5E of Patent Document 1 is re-displayed in FIG. 7, and the structure and the state of light rays will be described. FIG. 7 is a cross-sectional view of the lens 101 included in the light emitting diode lens (LED lighting device), in which a ray trace is drawn. Note that some symbols are changed. In FIG. 7, a lens 101 included in the light emitting device includes a sawtooth portion 102 utilizing refraction at a side portion and a funnel portion 103 having total internal reflection (TIR) property at an upper portion. A concave portion is provided at the lower portion of the lens, and an LED die (LED light source) (not shown) is disposed at a focal point existing in the concave portion.

  In FIG. 7, components emitted from the focused light at ± 40 ° or less with respect to the package vertical axis 104 are reflected by the funnel portion 103, emitted from the surface H, and directed to the side. Of the focused light, a component of 45 ° to 75 ° with respect to the package longitudinal axis 104 is emitted from the sawtooth portion 102. For example, light rays that are focused at 40 ° and 30 ° from a line perpendicular to the package longitudinal axis 104 exit laterally from surfaces E and D, respectively. Note that the surfaces G and F do not kick light emitted from the focal point. In addition, light rays that are focused at 10 ° and 20 ° from a line perpendicular to the package longitudinal axis 104 are emitted sideways from the surfaces C and B, respectively.

Japanese Patent Laying-Open No. 2003-8068 (FIG. 5E)

  As described above, the LED illumination device (light emitting diode package) shown in FIG. 7 has an LED light source (LED die) disposed at a position including the focal point of the bottom, and the lens 101 emits light from the LED light source sideways. Was emitted. However, since LED light sources usually have a planar extent that is not negligible with respect to the lens, the ray trace shown in FIG. 7 only displays a portion of the ray group. That is, when the lens 101 shown in FIG. 7 is placed on a planarly spread LED light source, the component that travels in an obliquely upward direction from among the light emission at the portion away from the focal point (for example, light emission near the end of the LED light source). Is once emitted from the surface of the serrated portion 102 (for example, surface D), then returns to the lens 101 from the surface of the serrated portion 102 (for example, surface G) again, and is obliquely inclined from another surface (for example, surface E). What emerges upward appears. As described above, when the lens 101 shown in FIG. 7 and the LED light source having a planar spread are combined, there is a problem that there is a large amount of light traveling obliquely upward.

Therefore, the present invention has been made in view of the above problems, and has a strong directivity in the upward direction.
An object of the present invention is to provide an LED illumination device capable of reducing light traveling obliquely upward when light emitted from an ED light source is directed to the side using reflection and refraction of a lens.

In order to achieve the above object, an LED illumination device according to the present invention is an LED illumination device including an LED light source and a lens disposed so as to surround the LED light source.
The lens includes a cylindrical surface, a downwardly conical first reflecting surface provided at the top, and an LED light source storage portion provided at the bottom for storing the LED light source,
The LED light source housing has an upper incident surface and a side incident surface,
The side entrance surface is inclined such that the upper end faces the side surface.

  In the LED lighting device of the present invention, the LED light source is housed in a lens housing portion provided at the bottom of the lens. At this time, most of the light emitted from the LED light source and incident on the lens from the upper incident surface is reflected by the first reflecting surface disposed above the upper incident surface and travels to the side. Further, the light emitted from the LED light source and incident on the lens from the side incident surface is largely refracted and directed in the side direction because the side incident surface is inclined toward the side surface.

  The lens may include a second conical reflecting surface facing downwards above the first reflecting surface.

  In the lens, the first reflecting surface and the upper incident surface may be divided to form a Fresnel.

  As described above, the LED illumination device according to the present invention has a side formed close to the LED light source when the light emission of the LED light source having strong directivity in the upward direction is directed to the side using the reflection and refraction of the lens. Since the partial incident surface refracts light that is directed obliquely upward on the inclined surface, the light directed obliquely upward can be reduced.

The perspective view of the LED lighting apparatus shown as 1st Embodiment of this invention. Sectional drawing of the LED lighting apparatus shown in FIG. Sectional drawing of the LED lighting apparatus shown in FIG. Sectional drawing of the LED lighting apparatus shown as 2nd Embodiment of this invention. Sectional drawing of the LED lighting apparatus shown as 3rd Embodiment of this invention. Explanatory drawing of Fresnelization in the LED lighting apparatus shown in FIG. Sectional drawing of the conventional LED lighting apparatus.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted. For the sake of explanation, the scale of the members is changed as appropriate.
(First embodiment)
First, the external appearance of the LED lighting device 10 shown as the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view of the LED lighting device 10 as viewed obliquely from above. In FIG. 1, the reflection surface 13 (first reflection surface) and the side surface 12 formed on the upper part of the lens 11 included in the LED illumination device 10 are observed. The lens 11 is generally cylindrical, its side surface 12 is cylindrical, and the reflecting surface 13 is recessed in a conical shape. At the bottom of the lens 11, there is an LED light source storage 14 (not shown). The LED light source storage unit 14 stores the LED light source 20 (see FIG. 2), and its bottom surface is open.

  Next, the structure of the LED lighting device 10 will be described in more detail with reference to FIG. FIG. 2 is a cross-sectional view illustrating the LED illumination device 10 shown in FIG. 1 so as to include the optical axis (center axis). As shown in FIG. 2, the LED illumination device 10 includes a lens 11 and an LED light source 20. The lens 11 includes a reflective surface 13 at the top and an LED light source storage 14 at the bottom. As described above, the reflecting surface 13 is a conical depression whose apex faces downward. The LED light source storage unit 14 is a space having a downward truncated cone shape whose upper surface is larger than the bottom surface, and the LED light source 20 is stored therein. In addition, the LED light source storage portion 14 has a flat upper incident surface 15 on the top surface and a side incident surface on the side surface, and the upper end of the side incident surface 16 is inclined toward the side surface 12 side of the lens 11. The LED light source 20 is a square or rectangular planar light source in a plan view.

  Next, the light emission characteristics of the LED lighting device 10 will be described with reference to FIG. FIG. 3 is a cross-sectional view of the LED illumination device 10 shown in FIG. In FIG. 3, the light beam L <b> 1 emitted upward from the LED light source 20 enters the lens 11 from the upper incident surface 15, is totally reflected by the reflecting surface 13, and then exits from the side surface 12 to the side of the LED illumination device 10. A light beam L2 emitted obliquely upward at a low angle from the LED light source 20 enters the lens 11 from the side incident surface 16. At this time, since the side incident surface 16 is inclined, the light beam L2 is largely refracted and then emitted from the side surface 12 to the side of the LED lighting device 10. Light rays that cannot be totally reflected by the reflecting surface 13 and are emitted obliquely upward from the reflecting surface 13 or rays that are not incident on the side incident surface 16 and are emitted obliquely upward from the side surface 12 are not shown.

In the LED light source storage unit 14, the LED light source 20 and the side incident surface 16 are close to each other, so that most of the light rays that do not reach the reflection surface 13 among the light rays emitted from the LED light source 20 are on the side incident surface 16. Incident. In the LED storage unit 14, the height of the upper incident surface 15 is first determined, and then the light is emitted from the center of the LED light source 20 and incident on the lens 11 while being refracted in the optical axis direction at the upper incident surface 15, and then the reflecting surface 13. It is preferable to determine the upper end position of the side incident surface 16 so that a light beam reaching the outer extended end of the side portion is obtained and the upper end of the side upper incident surface 16 is in contact with this light beam. In the LED lighting device 10, the reflecting surface 13, the upper incident surface 15, and the side incident surface 16 are curved surfaces or planes having a linear cross section, but these surfaces may have a curved cross section.
(Second Embodiment)
1 to 3, the LED light source 20 has a planar spread, and therefore the LED light source 20 is designed so that the light beam emitted from the center of the LED light source 20 is totally reflected by the reflecting surface 13. A part of the light beam emitted from the other part of the light 20 is not totally reflected at the reflection surface 13, and light leaks upward from the reflection surface 13. Therefore, as a second embodiment with reference to FIG. 4, an LED illumination device 40 that directs the light beam to be leaked to the side to further reduce the light leakage and increase the side light emission amount will be described. FIG. 4 is a cross-sectional view drawn to include the optical axis (center axis) of the LED lighting device 40. In FIG. 4, members and portions denoted by the same reference numerals as those in FIGS. 1 to 3 are the same as the members and portions of the LED lighting device 10, and description thereof is omitted.

In FIG. 4, the LED lighting device 40 includes a second reflecting surface 43 above the reflecting surface 13 (first reflecting surface). That is, the lens 41 included in the LED lighting device 40 has a flat bottom surface and a conical depression (second reflecting surface 43) on the upper surface of the lens 11 included in the LED lighting device 10 shown in FIGS. The lens 41a provided is superposed (attached). In the LED lighting device 40, the light beam emitted from the LED light source 20 and transmitted through the reflecting surface 13 is refracted away from the optical axis by the reflecting surface 13, and thus is easily totally reflected by the second reflecting surface 43. As a result, the amount of light directed to the side increases.
(Third embodiment)
The LED lighting device 10 shown in FIGS. 1 to 3 includes a conical reflection surface 13 that is inverted on the top of a lens 11, and a conical truncated LED light source storage unit 14 that faces downward at the bottom of the lens 11. It was. In general, a lens is divided into an annular shape around the optical axis so that a convex lens can be converted to a Fresnel lens, and a lens having an equivalent function is formed by combining the incident surface and the exit surface on the corresponding ring. Can be configured (hereinafter referred to as Fresnelization). Therefore, an LED lighting device 50 in which the lens 11 of the LED lighting device 10 shown in FIGS. 5 and 6, members and portions denoted by the same reference numerals as those in FIGS. 1 to 3 are the same as the members and portions of the LED lighting device 10, and description thereof is omitted. Moreover, in the LED lighting device 50, the reflective surface 13 of the LED lighting device 10 based on it is made into the convex surface.

  FIG. 5 is a cross-sectional view drawn to include the central axis (optical axis) of the LED lighting device 50. In FIG. 5, the LED illumination device 50 has a cylindrical shape, and has an LED light source storage portion 54 in which the LED light source 20 is disposed at the bottom of the lens 51, and a cavity 57 at the top. The LED light source storage unit 54 has an open upper surface and a side incident surface 56 provided on the side. The side entrance surface 56 has the same shape as the side entrance surface 16 shown in FIG. The cavity 57 once expands toward the upper part and then becomes narrower. In addition, the side surface of the cavity 57 has an annular shape with a serrated cross section, and each unevenness is composed of a piece 55 of the upper incident surface and a piece 53 of the reflecting surface. The unevenness in the cavity 57 becomes a Fresnelized portion.

  Next, the Fresnelization method will be described with reference to FIG. 6A is a cross-sectional view schematically showing a part of the LED lighting device 10 shown in FIG. 2 and the like, and FIG. 6B is a schematic view showing a part of the LED lighting device 50 shown in FIG. FIG. In the following description, reference instructions to FIGS. 6A and 6B are omitted unless otherwise specified.

  First, in FIG. 6A, the upper incident surface 15 and the reflecting surface 13 are divided into an annular shape for each angle α with the center of the LED light source 20 as the origin. At this time, a piece of the upper incident surface 15 sandwiched between the half lines m1, m2, and m3 indicating the boundaries divided by the angle α is 15a, 15b from the side incident surface 16 side, and a corresponding piece of the reflecting surface 13 is 13a, 13b. Next, in FIG. 6B, the piece 15a of the upper incident surface 15 is moved so that the right end of the piece 15a of the upper incident surface 15 coincides with the upper end of the side incident surface 56, thereby forming a piece 55a of the upper incident surface. Subsequently, the one piece 13a of the reflecting surface 13 is moved so that the lower end of the one piece 13a of the reflecting surface 13 coincides with the left end of the one piece 55a of the upper incident surface, thereby forming a piece 53a of the reflecting surface. At this time, the length of the piece 53a of the reflecting surface is adjusted so that the light beam emitted from the center of the LED light source 20 and passing through the right end of the piece 55a of the upper incident surface hits the upper right end of the piece 53a of the reflecting surface.

  Subsequently, the piece 15b of the upper incident surface 15 is moved so that the upper right end of the piece 53a of the reflecting surface coincides with the right end of the piece 15b of the upper incident surface 15, thereby forming a piece 55b of the upper incident surface. At this time, the length is adjusted so that the left terminal of the piece 55b of the upper incident surface is in contact with the half line m3. Subsequently, the lower end of the piece 13b of the reflecting surface 13 moves so as to coincide with the left end of the upper incident surface piece 55b to form a reflecting surface piece 53b. At this time, the length of the piece 53b of the reflecting surface is adjusted so that the light beam emitted from the center of the LED light source 20 and passing through the right end of the piece 55b of the upper incident surface hits the upper right end of the piece 53b of the reflecting surface. By repeating this process, the LED lighting device 10 shown in FIG. 2 and the like can be made Fresnel like the LED lighting device 50.

  Further, by finely dividing the annular shape at the time of Fresnelization, the outer shape of the LED lighting device 50 can be elongated as shown in FIG. The Fresnelization shown here can also be applied to the LED lighting device 50 shown in FIG.

10, 40, 50 ... LED lighting device,
11, 41, 51 ... lens,
12 ... side,
13: Reflecting surface (first reflecting surface),
13a, 13b, 53, 53a, 53b ... a piece of reflective surface,
14, 54 ... LED light source housing,
15 ... Upper entrance surface,
15a, 15b, 55, 55a, 55b ... a piece of the upper entrance surface,
16, 56 ... side entrance surface,
57 ... Cavity,
20 ... LED light source,
43. Second reflecting surface,
L1, L2 ... rays.

Claims (3)

In an LED lighting device comprising an LED light source and a lens arranged to surround the LED light source,
The lens is
A cylindrical side surface;
A downwardly conical first reflecting surface provided at the top;
An LED light source storage part provided at the bottom for storing the LED light source,
The LED light source housing has an upper incident surface and a side incident surface,
The LED illumination device according to claim 1, wherein the side incident surface is inclined such that an upper end faces the side surface.   2. The LED lighting device according to claim 1, wherein the lens includes a second conical downward reflecting surface on an upper portion of the first reflecting surface.   3. The LED illumination device according to claim 1, wherein the lens is formed by Fresnel by dividing the first reflection surface and the upper incident surface. 4.

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