JP2018190558A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device which can emit light in a rectangular form.SOLUTION: A lighting device according to an embodiment includes a light source and a lens. The light source emits light. The lens has optical elements arranged in a substantially lattice form on an emission surface which is a surface opposite to the light source.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lighting device.

  Conventionally, various illumination devices such as spotlights are provided. For example, there is an illuminating device used as a spotlight that emits light in a rectangular shape from an emission surface.

JP 2006-286615 A

  However, the conventional lighting device emits light in a rectangular shape by blocking the light. That is, the conventional illumination device has a problem that the emission efficiency is lowered by the amount of light blocking.

  This invention is made | formed in view of the above, Comprising: It aims at providing the illuminating device which can radiate | emit a light in a rectangular shape.

  In order to solve the above-described problems and achieve the object, an illumination device according to one embodiment of the present invention includes a light source that emits light and an optical element arranged in a substantially lattice shape on a surface opposite to the light source. A lens having a certain exit surface.

  According to one embodiment of the present invention, light distribution can be controlled in a rectangular shape.

FIG. 1 is a schematic exploded perspective view of a lighting device according to an embodiment. FIG. 2 is a schematic diagram of a lens according to the embodiment. FIG. 3A is a schematic diagram of an exit surface of the lens according to the embodiment. FIG. 3B is a schematic diagram of the optical element according to the embodiment. FIG. 3C is a schematic diagram of the optical element according to the embodiment. FIG. 4 is a diagram illustrating a light distribution of light emitted from the illumination device according to the embodiment. FIG. 5 is a schematic diagram of a cover lens according to the embodiment. FIG. 6 is a diagram illustrating directions of the first prism, the second prism, and the third prism according to the embodiment. FIG. 7 is a diagram illustrating a comparison result according to the presence or absence of a cover lens according to the embodiment.

  Hereinafter, a lighting device according to an embodiment will be described with reference to the drawings. In addition, this invention is not limited by embodiment shown below. In addition, the relationship between the dimensions of each element in the drawings, the ratio of each element, and the like may be different from the actual situation. Also, there are cases in which parts having different dimensional relationships and ratios are included between the drawings.

  First, the structure of the illumination device according to the embodiment will be described with reference to FIG. FIG. 1 is a schematic exploded perspective view of a lighting device according to an embodiment. FIG. 1 shows a three-dimensional orthogonal coordinate system including the Z-axis with the light emitting surface as the positive direction for easy understanding. Such an orthogonal coordinate system may be shown in other drawings used in the following description.

  The illumination device 1 shown in FIG. 1 is a so-called spotlight, and is used for illuminating an exhibit such as a museum. In the example of FIG. 1, the lighting device 1 can emit light in the positive direction of the Z axis.

  As shown in FIG. 1, the lighting device 1 according to the embodiment includes a heat sink member 11, a housing 12, an LED (Light Emitting Diode) 13 that is a light source, an LED holder 14, an adjustment member 15, and a reflector. 16, a lens holder 17, a lens 18, a cover lens 19, and a lens stopper 20.

  The heat sink member 11 dissipates heat generated by the LED 13. The housing 12 accommodates the adjustment member 15, the reflector 16, the lens holder 17, the lens 18, and the cover lens 19, and is connected to the heat sink member 11.

  The LED 13 is, for example, an RGB full color COB (Chip On Board) type LED. The LED holder 14 is a member that covers the LED 13 and protects the LED 13. The adjustment member 15 adjusts the position of the lens 18 and adjusts the distance between the LED 13 and the lens 18. For example, by sliding the adjustment member 15 in the circumferential direction, the distance between the LED 13 and the lens 18 can be reduced or increased.

  The reflector 16 is provided with an opening at a central position, and is formed in a conical shape recessed toward the opening, and reflects the light from the LED 13 toward the lens 18 side.

  The lens holder 17 is a member that accommodates the lens 18 and the cover lens 19. The lens 18 is a so-called Fresnel lens, and controls the light distribution angle of the light emitted from the LED 13. In addition, the illuminating device 1 which concerns on embodiment can control light distribution to a rectangular shape by providing an optical element in the output surface which is the main surface on the opposite side to LED13 of the lens 18. FIG. Details of this point will be described later with reference to FIG.

  The cover lens 19 is a member that covers the lens 18 and protects the lens 18. In addition, the illuminating device 1 according to the embodiment can make the emitted light closer to a rectangular shape by providing a prism that controls the light distribution of the light emitted from the lens 18 on one of the main surfaces of the cover lens 19. . Details of this point will be described later with reference to FIGS.

  The lens stopper 20 is a member for fixing the lens 18 and the cover lens 19 to the lens holder 17. By sliding the lens stopper 20 against the lens holder 17 in the circumferential direction, the lens 18 and the cover lens 19 can be fixed or removed.

  Next, details of the lens 18 will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing the configuration of the lens 18. 2 schematically shows a cross section along the X-axis of the lens 18 shown in FIG. As shown in FIG. 2, the exit surface, which is the main surface opposite to the LED 13 of the lens 18, has an optical element 18a.

  The optical element 18a further controls the light distribution in a rectangular shape with respect to the light whose light distribution is controlled by the prisms 18b and 18c provided on the incident surface which is the main surface facing the emission surface. The LED 13 is installed on the incident surface side of the lens 18.

  Here, in the conventional illumination device, in order to reduce color unevenness, for example, an illumination device including a diffusion element that diffuses light on the exit surface of a lens is known. On the other hand, in the illumination device 1 according to the embodiment, rectangular light distribution control is enabled by controlling the light distribution on both the incident surface and the exit surface of the lens 18. Thereby, in the illuminating device 1 which concerns on embodiment, light distribution can be controlled to a rectangular shape, without using the member which interrupts | emits the emitted light. Details of the optical element 18a will be described later with reference to FIGS. 3A to 3C.

  Moreover, the illuminating device 1 which concerns on embodiment has prism 18b, 18c in the entrance plane which is the main surface by the side of LED13 of the lens 18. FIG. The prism 18b is a refractive prism, and the prism 18c is a total reflection prism (TIR (Total Internal Reflection) prism), each of which is configured concentrically.

  Light incident from the LED 13 is refracted by the prism 18b and totally reflected internally by the prism 18c. Thereby, the incident angle of the light passing through the prism 18b and the prism 18c is controlled so as to be substantially perpendicular to the emission surface. The lens 18 may be configured without the prisms 18b and 18c.

  Next, details of the optical element 18a of the lens 18 will be described with reference to FIGS. 3A to 3C. FIG. 3A is a schematic diagram of an emission surface of the lens 18 according to the embodiment. 3B and 3C are schematic views of the optical element 18a according to the embodiment. FIG. 3A is a schematic view of the lens 18 as seen from the Z axis positive direction side. 3B is a schematic cross-sectional view of the lens 18 along the Y axis including the vertex 18da of the first prism 18d. FIG. 3C is a cross-sectional view of the lens 18 along the X axis including the vertex 18ea of the second prism 18e. It is a cross-sectional schematic diagram. In FIGS. 3B and 3C, the description of the prisms 18b and 18c is omitted.

  As shown in FIG. 3A, an optical element 18 a is formed on the exit surface of the lens 18. The optical element 18a is a substantially lattice-shaped prism including a plurality of first prisms 18d extending in a streak shape in the X-axis direction and a plurality of second prisms 18e extending in a streak shape in the Y-axis direction. That is, the optical element 18a has a surface shape in which the first prism 18d and the second prism 18e are combined. Further, the cross-sectional shapes in the short direction of the first prism 18d and the second prism 18e are substantially wave-shaped shapes each composed of two arcs and an inclined portion connecting them, and the Z-axis positive direction from the exit surface of the lens 18 is obtained. It is formed to be convex in the direction.

  By the way, in the illuminating device 1 which concerns on embodiment, the height from each vertex 18da and 18ea of each of the 1st prism 18d and the 2nd prism 18e to each bottom face 18db and 18eb, and the space | interval of the 1st prism 18d and the 2nd prism 18e. By adjusting the light distribution, it is possible to adjust the light distribution.

  Specifically, as shown in FIGS. 3B and 3C, the height h1 from the apex 18da of the first prism 18d to the bottom surface 18db of the first prism 18d is such that the apex 18ea of the second prism 18e extends to the second prism 18e. When the height is lower than the height h2 to the bottom surface 18eb, light can be diffused more widely in the X-axis direction side than in the Y-axis direction side.

  This is considered to be because the surface area or contact angle of the first prism 18d or the second prism 18e increases as the height h1 or the height h2 is increased. For example, by increasing the surface area, it is considered that light is diffused more widely in a direction substantially orthogonal to the direction in which the first prism 18d or the second prism 18e extends. In the above example, since the height h2 is higher than the height h1, light can be emitted in a substantially rectangular shape with the direction perpendicular to the second prism 18e as the longitudinal direction.

  The optical element 18a can be formed by forming a mold by the following method and transferring the shape of the mold to the exit surface of the lens 18. Specifically, first, a groove corresponding to the first prism 18d is formed on the mold by laser irradiation. In such a case, laser irradiation is performed on the mold so that the groove depth is substantially uniform. Subsequently, a groove corresponding to the second prism 18e is formed by laser irradiation in a direction substantially orthogonal to the first prism 18d with respect to the mold in which the groove corresponding to the first prism 18d is formed. In addition, the shape (depth) of the groove | channel corresponding to the 1st prism and 2nd prism formed in a metal mold | die can be adjusted by changing the laser irradiation conditions etc. at the time of laser processing.

  That is, by transferring the mold to the exit surface of the lens 18, optical elements 18a having different heights h1 and h2 are formed. However, in the laser processing step corresponding to the second prism 18e, the portion that overlaps the groove corresponding to the first prism 18d that has been processed first is partially deepened. That is, the portion where the top of the first prism 18d and the top of the second prism 18e overlap is partially increased.

  Next, the correlation between the pitch, height h1, height h2 of the first prism 18d or the second prism 18e and the light distribution of the light emitted from the lens 18 will be described with reference to FIG. FIG. 4 is a diagram illustrating a light distribution of light emitted from the illumination device 1 according to the embodiment. FIG. 4 shows the results when the distance between the LED 13 and the lens 18 is 25 mm.

  The pitch indicates the interval between the apexes 18da of the adjacent first prisms 18d. Note that, since the optical elements 18a are arranged in a substantially lattice shape, the interval and the interval between the apexes 18ea of the adjacent second prisms 18e are substantially equal.

  As shown in FIG. 4, the longer the pitch, the light distribution has a substantially cross shape. Specifically, when the pitch is 100 μm, the light distribution is substantially cross-shaped, and as the pitch is shortened to 80, 64, and 50 μm, the light distribution becomes closer to a rectangular shape from the cross shape.

  When the pitch is 32 μm, the light distribution is substantially rectangular. That is, in the illuminating device 1 which concerns on embodiment, it becomes possible to control light distribution to a rectangular shape by shortening a pitch.

  This is because the bottom surface of the optical element 18a is curved as shown in FIGS. 3B and 3C by shortening the pitch. In other words, in the illuminating device 1 according to the embodiment, the flat portion is not formed on the bottom surface of the optical element 18a by shortening the pitch.

  This is because when the pitch is increased, a flat portion is formed on the bottom surface of the optical element 18a, and light passing through the flat portion is not controlled by the optical element 18a, and the orientation approaches a circular shape. For this reason, in the illuminating device 1 which concerns on embodiment, it is preferable that a pitch is short so that a flat part may not be formed in the bottom face of the optical element 18a.

  The shape of the optical element 18a according to the present embodiment is a substantially wave shape in which the cross section includes two arcs and an inclined portion that connects the two arcs, but the present invention is not limited to such a shape, and the cross section is triangular. Other shapes such as may be used. Further, depending on the distance between the LED 13 and the lens 18, a flat portion may be provided on the bottom surface of the optical element 18a. In the above example, the case where the pitch of the first prism 18d and the pitch of the second prism are substantially equal is illustrated, but the pitch of both may be different.

  Next, the cover lens 19 according to the embodiment will be described with reference to FIGS. First, the outline of the cover lens 19 according to the embodiment will be described with reference to FIG. FIG. 5 is a diagram illustrating an outline of the cover lens 19 according to the embodiment.

  In FIG. 5, the cover lens 19 is viewed from the Z-axis negative direction side. That is, FIG. 5 is a diagram schematically illustrating an incident surface that is a main surface of the cover lens 19 on the LED 13 side.

  As shown in FIG. 5, the cover lens 19 has a plurality of third prisms 19a extending in a streak shape in the X-axis direction. The third prism 19 a is formed, for example, by transferring the shape of a mold irradiated with a laser to the incident surface of the cover lens 19. The third prism 19a is formed so that the cross section in the short direction is substantially arc-shaped and is convex from the incident surface of the cover lens 19 in the negative Z-axis direction.

  Here, the height of each third prism 19a is formed to be different depending on the X-axis coordinate. Specifically, as shown in the figure, each third prism 19a has the lowest height at the center of the cover lens 19 and gradually increases toward both ends. In other words, the third prism 19 a is formed such that its height increases from the center to the end of the cover lens 19.

  Thereby, it is considered that the third prism 19a can diffuse light widely in the Y-axis direction, which is the direction orthogonal to the third prism 19a, as it goes to the end. That is, the third prism 19a can effectively diffuse light in the Y-axis direction in the area A shown in FIG.

  Note that all the third prisms 19a may have a uniform height, or may be formed only at one end of the cover lens 19 in one direction (for example, a region surrounded by the area A). Good.

  Further, the third prism 19 a may be provided on the exit surface side of the cover lens 19, or the third prism 19 a may be formed on both the exit surface and the entrance surface of the cover lens 19. Further, instead of the cover lens 19, another member having the third prism 19a may be used.

  By providing the cover prism 19 with the third prism 19a, the number of parts can be reduced as compared with the case of using other members, and the reduction in emission efficiency can be suppressed by the amount of such other members. .

  Next, directions of the first prism 18d, the second prism 18e, and the third prism 19a will be described with reference to FIG. FIG. 6 is a diagram illustrating the orientation of the first prism 18d, the second prism 18e, and the third prism 19a.

  In FIG. 6, only the first prism 18d, the second prism 18e, and the third prism 19a are shown for easy understanding. As described above, the first prism 18 d and the second prism 18 e are formed on the exit surface of the lens 18, and the third prism 19 a is formed on the entrance surface of the cover lens 19.

  Hereinafter, a direction in which the first prism 18d extends is referred to as a first direction, and a direction in which the second prism 18e extends is referred to as a second direction. A direction in which the third prism 19a extends is referred to as a third direction.

  As shown in FIG. 6, when the first direction and the second direction are substantially orthogonal, and the height h1 is lower than the height h2 as shown in FIGS. 3B and 3C, the third prism 19a Three directions are arranged in a direction orthogonal to the second direction.

  That is, the third prism 19a is arranged in a direction orthogonal to the prism having the higher height among the first prism 18d and the second prism 18e. Thereby, the light passing through the third prism 19a is effectively diffused in a direction substantially orthogonal to the first direction.

  Note that the first prism 18d and the second prism 18e do not necessarily need to be substantially orthogonal, but may be crossed. Even in such a case, the cover lens 19 may be arranged in a direction in which the third prism 19a is substantially orthogonal to the second prism 18e. Depending on the shape of the third prism 19a, the lens 18 and the cover lens 19 may be arranged in a direction in which the third direction and the first direction are orthogonal to each other. In addition, the first direction or the second direction and the third direction do not necessarily have to be substantially orthogonal.

  Next, a comparison result of light distribution with and without the cover lens 19 having the third prism 19a will be described with reference to FIG. FIG. 7 is a diagram illustrating a comparison result based on the presence or absence of the cover lens 19 according to the embodiment.

  As shown in FIG. 7, when there is no cover lens 19, the light distribution has a shape having a recess at the center, and when the cover lens 19 is provided, the light distribution is closer to a rectangular shape than when there is no cover lens. Become.

  This is presumably because light is diffused by the third prism 19a in a direction that eliminates the recess. That is, the cover lens 19 can disperse light in a direction orthogonal to the first direction, thereby eliminating the dent and making the light distribution closer to a rectangular shape.

  In other words, in the illumination device 1 according to the embodiment, the lens 18 and the cover lens 19 are arranged so that the third direction is substantially orthogonal to the second direction, so that the light emitted from the cover lens 19 is more rectangular. It can be close to the shape.

  As described above, in the illumination device 1 according to the embodiment, the light source (LED 13) emits light. The lens 18 has optical elements 18a arranged in a substantially lattice pattern on the exit surface that is the surface opposite to the light source. Thereby, light can be emitted in a rectangular shape.

  Further, as described above, in the illumination device 1 according to the embodiment, the optical element 18a has a shape with a curved bottom surface. Thereby, light can be diffused in a rectangular shape.

  Further, as described above, in the illumination device 1 according to the embodiment, the optical element 18a includes the plurality of first prisms 18d extending in a streak shape in the first direction and the streaks in the second direction intersecting the first direction. The surface shape is a combination of a plurality of second prisms 18 e extending in a straight line. Thereby, light can be efficiently irradiated in a rectangular shape.

  In addition, as described above, in the illumination device 1 according to the embodiment, a cover (on one side of the main surface) that includes a plurality of third prisms 19a that are arranged on the exit surface side of the lens 18 and extend in a streak shape in the third direction. A cover lens 19) is further provided. Thereby, the light distribution of the light emitted from the lens 18 can be further controlled by the cover lens 19.

  Further, as described above, in the lighting device 1 according to the embodiment, the cover is arranged in a direction in which the third direction is substantially orthogonal to the first direction or the second direction. Thereby, light can be diffused in a direction orthogonal to the first direction or the second direction.

  Further, as described above, in the illumination device 1 according to the embodiment, the first direction and the second direction are substantially orthogonal, and the height h1 from the vertex 18da of the first prism 18d to the bottom surface 18db of the first prism 18d is When the height h2 from the apex 18ea of the second prism 18e to the bottom surface 18eb of the second prism 18e is lower than the height h2, the third direction is arranged in a direction substantially orthogonal to the second direction. Thereby, the emitted light can be made closer to a rectangular shape.

  Further, as described above, in the illumination device 1 according to the embodiment, the height of the third prism 19a gradually increases from the center of the cover toward the end along the third direction. Thereby, the emitted light can be brought closer to a rectangular shape more effectively.

  Further, as described above, in the illumination device 1 according to the embodiment, the cover is the cover lens 19 that protects the lens 18. As a result, it is possible to suppress the number of components and suppress a decrease in emission efficiency.

  In the above-described embodiment, the case where the exit surface of the lens 18 is circular has been described. However, the present invention is not limited to this. That is, the exit surface of the lens 18 may have another shape such as an elliptical shape, a rectangular shape, or a triangular shape. The lens 18 is not limited to a flat plate shape, and may be non-uniform in thickness, for example, on a spherical surface.

  Further, the present invention is not limited by the above embodiment. What was comprised combining each component mentioned above suitably is also contained in this invention. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

DESCRIPTION OF SYMBOLS 1 Illuminating device 11 Heat sink member 12 Case 13 LED (an example of a light source)
14 LED holder 15 Adjustment member 16 Reflector
17 Lens holder 18 Lens 18a Optical element 18b, c Prism 18d First prism 18e Second prism 19 Cover lens 19a Third prism 20 Lens stopper

Claims (8)

A light source that emits light;
An illumination device comprising: a lens having optical elements arranged in a substantially lattice pattern on an exit surface which is a surface opposite to the light source. The optical element is
The lighting device according to claim 1, wherein the bottom surface has a curved shape. The optical element is
The surface shape is a combination of a plurality of first prisms extending linearly in a first direction and a plurality of second prisms extending linearly in a second direction intersecting the first direction. The lighting device described in 1.   The lighting device according to claim 3, further comprising a cover that is disposed on the light exit surface side of the lens and has a plurality of third prisms extending in a streak shape in a third direction on one of the main surfaces. The cover is
The lighting device according to claim 4, wherein the third direction is arranged in a direction substantially orthogonal to the first direction or the second direction. The lens is
The first direction and the second direction are substantially orthogonal,
The cover is
When the height from the top of the first prism to the bottom surface of the first prism is lower than the height from the top of the second prism to the bottom surface of the second prism, the third direction is the second direction. The lighting device according to claim 5, wherein the lighting device is arranged in a substantially orthogonal direction. The third prism is
The lighting device according to any one of claims 4 to 6, wherein the height gradually increases from the center of the cover toward the end portion along the third direction. The cover is
The illumination device according to claim 4, wherein the illumination device is a cover lens that protects the lens.