WO2024080099A1

WO2024080099A1 - Lighting device

Info

Publication number: WO2024080099A1
Application number: PCT/JP2023/034403
Authority: WO
Inventors: 貴裕池田; 哲也小杉; 文博高橋; 亮介久次米; 政男遠藤
Original assignee: パイフォトニクス株式会社
Priority date: 2022-10-14
Filing date: 2023-09-22
Publication date: 2024-04-18

Abstract

A lighting device (1) comprises: a plurality of light sources (31), (32) that are provided substantially on the same plane; a condensing lens (24) that condenses light emitted from the plurality of light sources (31), (32); and a correcting plate (40) that is interposed between the condensing lens (24) and at least one light source (32) among the plurality of light sources (31), (32), and that changes the condensing position with respect to the propagation direction of the light emitted from the at least one light source (32). The plurality of light sources (31), (32) include: a first light source (31); and a second light source (32) that is provided further outward with respect to the optical axis (OA) of the condensing lens (24) than the first light source. The correcting plate (40) is interposed between the second light source (32) and the condensing lens (24).

Description

Lighting equipment

The present invention relates to a lighting device.

There is a known lighting device that uses a focusing lens to focus light emitted from multiple light sources and irradiates an object with the light. For example, Patent Document 1 discloses a lighting device that illuminates the outer lane markings on the road.

JP 2002-260401 A

The technology disclosed in Patent Document 1 uses a single focusing lens to focus light from multiple light sources, which inevitably results in the problem of some of the illumination light being blurred due to aberration. Combining multiple lenses to eliminate this aberration is one option, but this would entail high manufacturing costs.

The present invention has been made to solve the problems described above, and aims to provide a lighting device that can reduce blurring of illumination light collected from multiple light sources with a simple configuration.

The lighting device according to the present invention is characterized by comprising a plurality of light sources arranged on approximately the same plane, a focusing lens that focuses the light emitted from the plurality of light sources, and a correction plate that is interposed between at least some of the plurality of light sources and the focusing lens and changes the focusing position relative to the traveling direction of the light emitted from at least some of the light sources.

The present invention provides an illumination device that can reduce blurring of illumination light produced by concentrating light from multiple light sources with a simple configuration.

FIG. 1 is a perspective view of a lighting device according to a first embodiment; FIG. 1 is a cross-sectional view of a main body of an illumination device according to a first embodiment taken along a front-rear direction. FIG. 1 is a schematic diagram for explaining light rays from a light source of an illumination device and illumination light irradiated onto an illumination surface; FIG. 4 is a diagram showing a lighting device according to Example 1 of the first embodiment, as viewed from the arrow IVa in FIG. FIG. 4B is a cross-sectional view of the illumination device according to Example 1 of the first embodiment taken along the line bb in FIG. 4A. FIG. 4 is a diagram showing a lighting device according to Example 2 of the first embodiment, as viewed from the arrow IVa in FIG. FIG. 5B is a cross-sectional view of the illumination device according to Example 2 of the first embodiment taken along the line bb in FIG. 5A. FIG. 4 is a diagram showing a lighting device according to Example 3 of the first embodiment, as viewed from the arrow IVa in FIG. FIG. 6B is a cross-sectional view of a lighting device according to Example 3 of the first embodiment taken along the line bb in FIG. 6A. FIG. 13 is a diagram showing illumination light from an illumination device according to Example 2 of the first embodiment, in the case where there is no correction plate; FIG. 13 is a diagram showing illumination light from an illumination device according to Example 2 of the first embodiment, in which a correction plate is provided; FIG. 4 is a diagram showing a lighting device according to a second embodiment, as viewed in a direction corresponding to the arrow IVa in FIG. FIG. 8B is a cross-sectional view of the illumination device according to the second embodiment taken along the line bb in FIG. 8A. FIG. 4 is a diagram showing a lighting device according to a third embodiment, as viewed in a direction corresponding to the arrow IVa in FIG. FIG. 9B is a cross-sectional view of the illumination device according to the third embodiment taken along the line bb in FIG. 9A. FIG. 13 is a diagram showing a lighting device according to a fourth embodiment, as viewed in a direction corresponding to the arrow IVa in FIG. FIG. 10B is a cross-sectional view of the illumination device according to the fourth embodiment taken along the line bb in FIG. 10A. FIG. 13 is a diagram showing a lighting device according to a fifth embodiment, as viewed in a direction corresponding to the arrow IVa in FIG. FIG. 11B is a cross-sectional view taken along the line bb in FIG. 11A showing the illumination device according to the fifth embodiment; FIG. 13 is a diagram showing a lighting device according to a sixth embodiment, as viewed in a direction corresponding to the arrow IVa in FIG. FIG. 12B is a cross-sectional view taken along the line bb in FIG. 12A, showing an illumination device according to a sixth embodiment; FIG. 13 is a diagram showing a lighting device according to a seventh embodiment, as viewed from a direction corresponding to the arrow IVa in FIG. FIG. 13B is a cross-sectional view taken along the line bb in FIG. 13A showing the illumination device according to the seventh embodiment. FIG. 13B is a cross-sectional view taken along the line cc in FIG. 13A showing the illumination device according to the seventh embodiment; FIG. 13 is a diagram showing an illumination device according to an eighth embodiment, as viewed in a direction corresponding to the arrow IVa in FIG. FIG. 14B is a cross-sectional view of the illumination device according to the eighth embodiment taken along the line bb in FIG. 14A. FIG. 13 is a diagram showing a lighting device according to a ninth embodiment, as viewed in a direction corresponding to the arrow IVa in FIG. FIG. 15B is a cross-sectional view of the illumination device according to the ninth embodiment taken along the line bb in FIG. 15A. FIG. 13 is a diagram showing a linear illumination light obtained by changing the lens of the illumination device according to the ninth embodiment, in the case where there is no correction plate. FIG. 13 is a diagram showing a case where the lens of the illumination device according to the ninth embodiment is changed to form a line-shaped illumination light, and shows a case where a correction plate is provided. FIG. 13 is a diagram showing a lighting device according to a tenth embodiment, as viewed in a direction corresponding to the arrow IVa in FIG. 2 . FIG. 17B is a cross-sectional view of the illumination device according to the tenth embodiment taken along the line bb in FIG. 17A. FIG. 13 is a diagram showing an illumination device according to an eleventh embodiment, as viewed in a direction corresponding to the arrow IVa in FIG. FIG. 18B is a cross-sectional view taken along the line bb in FIG. 18A showing an illumination device according to an eleventh embodiment. FIG. 12 is a diagram showing a lighting device according to a twelfth embodiment, as viewed in a direction corresponding to the arrow IVa in FIG. 2; FIG. 19B is a cross-sectional view of the illumination device according to the twelfth embodiment taken along the line bb in FIG. 19A. FIG. 11 is a top view showing an example of use of the lighting device according to the second embodiment, in which the lighting device is attached to an overhead crane and used.

Below, a lighting device according to a preferred embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
First, an overview of the illumination device of the first embodiment will be described. In this embodiment, illumination devices according to three examples will be described, and each example has a first light source disposed at the center and a second light source surrounding the first light source. In each example, the distance of the second light source from the first light source is different from each other, and the difference in distance results in different dimensions of the correction plate as an optical member.

(Overview of lighting device 1)
1, the lighting device 1 has a base unit 10 placed on a floor, a workbench, or the like, and a main body unit 20 supported by the base unit 10 so as to be rotatable about a horizontal axis. In the following description, the direction in which the main body unit 20 emits light is referred to as the forward direction, and the opposite direction is referred to as the rearward direction, and these front and rear directions will be used appropriately.

The main body 20 has a hollow box-shaped case 21 that is open at the front, and a translucent protective cover 22 that covers the opening of the case 21. As shown in FIG. 2, the main body 20 has a circuit board 25 on which multiple light sources 30 are provided, a focusing lens 24 that focuses the light emitted from the multiple light sources 30, and a correction plate 40 provided between the multiple light sources 30 and the focusing lens 24, in a storage space 23 surrounded by the case 21 and the protective cover 22. The planar dimensions of the main body 20 when viewed from the front are, for example, 100 mm x 100 mm.

The multiple light sources 30 are provided on a flat circuit board 25 and are arranged on the same plane. The multiple light sources 30 include a first light source 31 located in the center of the main body 20 when viewed from the front, and a second light source 32 located around the first light source 31 and outside the first light source 31. The first light source 31 is arranged on the optical axis OA of the focusing lens 24. In other words, the second light source 32 is provided outside the optical axis OA. The first light source 31 and the second light source 32 are composed of, for example, LEDs (Light Emitting Diodes), but the type of light source is arbitrary. The rectangular circuit board 25 is, for example, 60 mm x 60 mm in size.

The correction plate 40 is made of, for example, acrylic resin, and is arranged parallel to the circuit board 25. A circular opening 40a is formed in the center of the correction plate 40. Light from the second light source 32 arranged on the outside enters the correction plate 40, passes through the inside, and then exits toward the condenser lens 24. Meanwhile, light emitted from the first light source 31 passes through the opening 40a toward the condenser lens 24. In this way, the correction plate 40 is an optical component that changes the direction of light that enters the correction plate 40 from the second light source 32 arranged on the outside.

The focusing lens 24 is, for example, a Fresnel lens, and is arranged near the rear of the protective cover 22. The focusing lens 24 is arranged so that its optical axis OA passes through the main body 20 in the front-to-rear direction and through the center of the main body 20. The optical axis OA is a straight line passing through the center and focal point of the focusing lens. The focusing lens 24 focuses light emitted radially from multiple light sources 30 arranged at the rear, and emits it forward from the protective cover 22. This makes it possible to irradiate illumination light from the multiple light sources 30 onto an irradiation surface away from the lighting device 1.

(Role of Correction Plate 40)
Before describing the details of the illumination device 1, the role of the correction plate 40 provided between the multiple light sources 30 and the condenser lens 24 will be described with reference to Fig. 3. In Fig. 3, the correction plate 40 is not provided corresponding to the second light source 32a on the upper side of the figure, and the emitted light does not pass through the correction plate 40. On the other hand, the correction plate 40 is provided corresponding to the second light source 32b on the lower side of the figure, and the emitted light passes through the correction plate 40.

When illuminating a wall 50 (illumination surface) away from the lighting device 1, the light from the first light source 31 arranged at the center of the lighting device 1 (on the optical axis OA of the condenser lens 24) is adjusted to be condensed on the wall 50. In FIG. 3, the light beams L1, L2, and L3 from the first light source 31 and the light beams L1', L2', and L3' after passing through the condenser lens 24 are illustrated with solid lines. In this way, the light beams after passing through the condenser lens are marked with a "'". The images of the illumination light beams 51, 52, and 53 irradiated on the wall 50 by the light from each light source are illustrated as circles. The illumination light beam 51 from the first light source 31 is drawn as a compact circle, indicating that the light from the first light source 31 is sufficiently condensed by the condenser lens 24 and there is no blurring in the illumination light beam 51.

3, the light rays L4 and L5 from the second light source 32a at the top of the figure and the light rays L4' and L5' after these light rays L4 and L5 pass through the condenser lens 24 are shown by dashed lines. The image of the illumination light 52 from the second light source 32a is shown by a dashed circle. The range of the illumination light 52 from the second light source 32a is wider than the range of the illumination light 51 from the first light source 31. In other words, the illumination light 52 is once condensed in front of the wall 50 and then spreads slightly to the wall 50, so that the light is not sufficiently condensed and is blurred. The cause of this lack of condensation and blurring is the occurrence of aberration due to curvature of field. This aberration causes a phenomenon in which the light from a light source located farther away from the optical axis OA of the Fresnel lens is not sufficiently condensed.

In order to correct such aberration and change the focusing position relative to the traveling direction of the emitted light, a correction plate 40 as an optical member is inserted between the focusing lens 24 and the second light source 32. In FIG. 3, the light rays L6, L7a, L7b, and L7c from the second light source 32b are shown by dashed lines, as are the light rays L6' and L7' after the light rays L6 and L7c pass through the focusing lens 24. The image of the illumination light 53 from the second light source 32b is shown by a dashed circle. The range of the illumination light 53 from the second light source 32b is narrower than the range of the illumination light 52 from the second light source 32a, and is approximately the same as the range of the illumination light 51. In other words, the light from the second light source 32b is sufficiently focused, and the illumination light 53 is less blurred.

The reason why the illumination light is condensed and blurring is reduced by interposing the correction plate 40 in this manner will be explained. First, the light ray L6 that is perpendicularly incident on the correction plate 40 from the second light source 32b reaches the condensing lens 24 without being changed in direction by the correction plate 40. On the other hand, the light ray L7a that is obliquely incident on the correction plate 40 from the second light source 32b is refracted when it enters the correction plate 40 to become a light ray L7b that is nearly perpendicular to the correction plate 40, and is further refracted when it leaves the correction plate 40 to become a light ray L7c that faces the same direction as the light ray L7a and reaches the condensing lens 24. If a virtual light ray L7c' is drawn by extending this light ray L7c backward, this virtual light ray L7c' can be considered to be a light ray emitted from the second light source 32b' by moving the second light source 32b forward in a pseudo manner. That is, inserting the correction plate 40 has the effect of moving the second light source 32b forward, which makes it possible to change the focusing position relative to the traveling direction of the light emitted by the focusing lens 24. As a result, by making the correction plate to an appropriate thickness, the focusing position of the focusing lens 24 can be set to the desired position.

In the three embodiments described below, the distance from the optical axis OA to the light source is different from one another, and the thickness of the correction plate is made different according to the distance. Here, the distance from the optical axis OA, which is a straight line, refers to the perpendicular distance to the optical axis OA. For example, in FIG. 4B, the distance from the optical axis OA to the second light source 32 is the direction indicated by the distance d1 in the in-plane direction of the circuit board 25 perpendicular to the optical axis OA. Specifically, the second light source 32 arranged around the first light source 31 is arranged on a concentric circle 26 with a small diameter as shown in FIG. 4A, on a circle 27 with a diameter larger than the circle 26 as shown in FIG. 5A, or on a circle 28 with a diameter larger than the circle 27 as shown in FIG. 6A. In this way, the distance from the optical axis OA of the second light source 32 differs in each embodiment, and various dimensions of the correction plate in each embodiment are determined by this. In addition, in each of Figures 4A to 6B, attention is focused on the circuit board 25 of the lighting device 1 and the correction plate 40 mounted on the circuit board 25, and other configurations are omitted from the illustration. Also, as shown by the two-dot chain lines, the

circles

26, 27, and 28 are not displayed on the circuit board 25, but are imaginary circles set on the circuit board 25 to make it easier to understand the arrangement of the second light source 32. Furthermore, although the dimensions of the three embodiments are different, the basic configuration is the same. Therefore, in each of Figures 4A to 6B, parts that have the same basic configuration are given the same reference numerals.

(Structural details of the lighting device 1 according to the first embodiment)
Details of the lighting device 1 according to the first embodiment will be described with reference to Figs. 4A and 4B. As shown in Fig. 4A, the circuit board 25 is provided with a first light source 31 on the optical axis OA of the condenser lens 24 (the center of the lighting device) and a plurality of second light sources 32 arranged around the first light source 31. A total of 12 second light sources 32 are arranged at equal angular intervals on the circumference of a circle 26 centered on the optical axis OA. In this way, the plurality of second light sources 32 are arranged on the circuit board 25 at equal angular intervals. As shown in Fig. 4B, the second light source 32 is arranged at a position spaced apart from the first light source 31 on the optical axis OA by a distance d1. That is, the radius of the circle 26 is the same as the distance d1.

As shown in FIG. 4B, the correction plate 40 is connected to the circuit board 25 via bolts 42 provided at the four corners, with a spacer 41 interposed between the circuit board 25 and the correction plate 40. The spacer 41 is provided with a height that allows space to be secured between the circuit board 25 and the correction plate 40 for installing electronic components. The correction plate 40 is rectangular when viewed from the front, and is formed from a flat plate with a thickness of t1. A circular opening 40a with a diameter D1, for example, is formed in the center of the correction plate 40. The diameter D1 is smaller than the diameter of the circle 26. By providing the opening 40a in the center of the correction plate 40 in this way, when viewed from the front, the multiple second light sources 32 are covered by the correction plate 40, while the first light source 31 is exposed from the opening 40a and is not covered by the correction plate 40.

(Structural details of the lighting device 1 according to the second embodiment)
Next, the details of the lighting device 1 according to the second embodiment will be described with reference to Figs. 5A and 5B. As shown in Fig. 5A, the circuit board 25 is provided with a first light source 31 on the optical axis OA of the condenser lens 24 (the center of the lighting device) and a plurality of second light sources 32 arranged around the first light source 31. A total of 24 second light sources 32 are arranged at equal angular intervals on the circumference of a circle 27 centered on the optical axis OA. In this way, the plurality of second light sources 32 are arranged on the circuit board 25 at equal angular intervals. As shown in Fig. 5B, the second light source 32 is arranged at a position separated from the first light source 31 by a distance d2. The distance d2 is greater than the distance d1 shown in Fig. 4B. The radius of the circle 27 is the same as the distance d2. Thus, in the second embodiment, more second light sources 32 are arranged on a larger circle 27 that is further outward from the optical axis OA than in the first embodiment.

As shown in FIG. 5B, the correction plate 40 is connected to the circuit board 25 via bolts 42 provided at the four corners, with a spacer 41 interposed between the correction plate 40 and the circuit board 25. The correction plate 40 has a thickness t2, which is thicker than the thickness t1 shown in FIG. 4B. A circular opening 40a having a diameter D2, for example, is formed in the center of the correction plate 40. The diameter D2 is smaller than the diameter of the circle 27. Thus, in Example 2, the second light source 32 is positioned on the outside (away from the optical axis OA) and is therefore more susceptible to aberration than in Example 1, so the thickness of the correction plate 40 is made thicker. In addition, if the thickness of the correction plate 40 is made thicker, the light from the first light source 31 that is emitted radially becomes more likely to enter the correction plate 40, resulting in a decrease in the illuminance of the illumination light. In order to prevent such a decrease in illuminance, the diameter D2 of the opening 40a is made larger than the diameter D1 in Example 1.

(Structural details of the lighting device 1 according to the third embodiment)
Next, the details of the lighting device 1 according to the third embodiment will be described with reference to FIGS. 6A and 6B. As shown in FIG. 6A, the circuit board 25 is provided with a first light source 31 on the optical axis OA of the condenser lens 24 (the center of the lighting device) and a plurality of second light sources 32 arranged around the first light source 31. A total of 24 second light sources 32 are arranged at equal angular intervals on the circumference of a circle 28 centered on the optical axis OA. In this way, the plurality of second light sources 32 are arranged on the circuit board 25 at equal angular intervals. As shown in FIG. 6B, the second light source 32 is arranged at a position separated by a distance d3 from the first light source 31. The distance d3 is greater than the distance d2 shown in FIG. 5B. The radius of the circle 28 is the same as the distance d3. Thus, in the third embodiment, the second light source 32 is arranged on a larger circle 28 further outwardly away from the optical axis OA, as compared with the second embodiment.

As shown in FIG. 6B, the correction plate 40 is connected to the circuit board 25 via bolts 42 provided at the four corners, with a spacer 41 interposed between the correction plate 40 and the circuit board 25. The correction plate 40 has a thickness t3, which is thicker than the thickness t2 shown in FIG. 5B. A circular opening 40a having a diameter D3, for example, is formed in the center of the correction plate 40. The diameter D3 is smaller than the diameter of the circle 28. Thus, in Example 3, compared to Example 2, the second light source 32 is positioned on the outside (away from the optical axis OA) and is therefore more susceptible to aberration, so the thickness of the correction plate 40 is made thicker. In addition, when the thickness of the correction plate 40 is made thicker, the light from the first light source 31 that is emitted radially becomes more likely to enter the correction plate 40, so the diameter D3 of the opening 40a is made even larger.

(Effect of correction plate)
Next, the effect of providing the correction plate 40 on the illumination light will be described with reference to Figures 7A and 7B using Example 2 as an example. In Example 2, first, the light from the first light source 31 arranged in the center, which is less affected by the correction plate 40, was set to be focused on the irradiation surface, and then the correction plate 40 was inserted to verify what difference was made in the focusing state of the illumination light.

In the illumination device of Example 2, when comparing the case where light is emitted without using the correction plate 40 as shown in FIG. 7A with the case where light is emitted with the correction plate 40 inserted as shown in FIG. 7B, the case where the correction plate 40 shown in FIG. 7B is inserted can be recognized as illumination light that is less blurred and more concentrated.

By inserting the correction plate 40 in this way, the illumination light can be recognized as focused with less blur, as shown in Figures 7A and 7B. This effect can also be achieved with a simple configuration in which the outer light source is covered with a correction plate 40 made of acrylic resin.

The thickness of the correction plate 40 in the above examples 1 to 3 was determined by examining the value that would allow the light from the second light source 32 to be focused on the irradiation surface.

(Embodiment 2)
In the above-mentioned embodiment 1, the second light sources are arranged on one circle, but in the present embodiment, the second light sources are provided on the circumference of three concentric circles having different diameters centered on the optical axis OA, which is different from embodiment 1. Regarding the illumination device 100 according to embodiment 2, the differences from embodiment 1 will be described with reference to Figures 8A and 8B, and the same reference numerals will be used for the configurations common to the above-mentioned embodiment 1, and duplicated description will be omitted.

8A, the circuit board 125 is provided with a first light source 131 arranged on the optical axis OA of the condenser lens 24 (FIG. 2) (the center of the lighting device 100), a plurality of second light sources 132 arranged on the circumference of a circle 26 centered on the optical axis OA, a plurality of third light sources 133 arranged on the circumference of a circle 27 centered on the optical axis OA, and a plurality of fourth light sources 134 arranged on the circumference of a circle 28 centered on the optical axis OA. The radii of the circle 26, the circle 27, and the circle 28 are as described with reference to FIG. 4B and the like. A total of 12 second light sources 132 are arranged at equal angular intervals at a position separated by a distance d1 from the first light source 131. In addition, 24 third light sources 133 are arranged at equal angular intervals at a position separated by a distance d2 from the first light source 131. In addition, 24 fourth light sources 134 are arranged at equal angular intervals at a position separated by a distance d3 from the first light source 131. In addition, in FIG. 8A, the circle 28 overlaps with the solid line representing the correction plate 40, and is not illustrated as a two-dot chain line. In addition, the second light source 132, the third light source 133, and the fourth light source 134 arranged around the first light source 131 arranged on the optical axis OA may be collectively referred to as the second light source.

The correction plate 140 is formed from a flat plate made of acrylic resin with a thickness of t3. A bowl-shaped recess 140a is formed in the center of the correction plate 140. When the correction plate 140 is cut along a cross-sectional line passing through the optical axis OA, the curved surface that defines the recess 140a is expressed by a curve as shown in FIG. 8B. As a result, the first light source 131 arranged in the center is not covered by the correction plate 140, and the front of the second light source 132, the third light source 133, and the fourth light source 134, which are located away from the optical axis OA, can be covered by the correction plate 140, which has a curved thickness. In this way, the correction plate 140 changes its thickness according to the distance from the optical axis OA. Note that the distance from the optical axis OA is the perpendicular distance to the optical axis OA. As a result, the focusing position in the traveling direction of light from a light source located farther away from the optical axis OA, which is susceptible to aberration, can be changed by the thick correction plate. The effect is as described above.

(Embodiment 3)
Next, the illumination device 200 according to the third embodiment will be described with reference to FIGS. 9A and 9B. The illumination device 200 according to the third embodiment has a different shape of the recess 240a of the correction plate 240 from that of the second embodiment, but the other configurations are the same. The correction plate 240 is formed from a flat plate made of acrylic resin with a thickness t3. A recess 240a is formed in the center of the correction plate 240, which is hollowed out in a truncated cone shape. When the correction plate 240 is cut along a cross-sectional line passing through the optical axis OA as shown in FIG. 9A, the curved surface defining the recess 240a is represented by a straight line as shown in FIG. 9B. As a result, the first light source 131 arranged in the center is not covered by the correction plate 240, and the front of the second light source 132, the third light source 133, and the fourth light source 134 away from the optical axis OA can be covered by the correction plate 240 whose plate thickness is linearly increased. This allows the correction plate having a large thickness to change the focusing position in the traveling direction of light from a light source disposed farther outward from the optical axis OA, which is susceptible to the effects of aberration.

(Embodiment 4)
Next, the illumination device 300 according to the fourth embodiment will be described with reference to Figs. 10A and 10B. The illumination device 300 according to the present embodiment is different from the illumination device 200 according to the third embodiment in that the plate thickness of the correction plate 340 increases stepwise from the center to the outside. As shown in Fig. 10B, the correction plate 340 has a first correction plate 341 having a thickness t1, a second correction plate 342 having a thickness t4 overlapped on the first correction plate 341, and a third correction plate 343 having a thickness t5 overlapped on the second correction plate 342. The first correction plate 341, the second correction plate 342, and the third correction plate 343 are rectangular when viewed from the front and have the same outer dimensions.

The first compensation plate 341 faces the circuit board 125 and has a circular opening 341a centered on the optical axis OA. The second compensation plate 342 is superimposed on the front surface of the first compensation plate 341 and has a circular opening 342a centered on the optical axis OA. The diameter of the opening 342a is larger than the diameter of the opening 341a. The third compensation plate 343 is superimposed on the front surface of the second compensation plate 342 and has a circular opening 343a centered on the optical axis OA. The diameter of the opening 343a is larger than the diameter of the opening 342a.

In this way, by stacking a correction plate with a large diameter opening on top of a correction plate with a small diameter opening, a correction plate 340 is formed whose thickness increases in a stepped manner from the center to the outside. By covering the circuit board 125 with the correction plate 340 formed in this way, the first light source 131 disposed in the center (on the optical axis OA) is open to the front through the

openings

341a, 342a, and 343a formed in the correction plate 340, as shown in Figures 10A and 10B.

The second light source 132, which is located at a distance d1 from the first light source 131, is covered at its front by a first correction plate 341 with a thickness t1. The relationship between the distance from the center of this second light source 132 and the thickness of the correction plate 340 that covers its front is the same as the relationship between the distance from the center of the second light source 32 and the thickness of the correction plate 40 shown in Figures 4A and 4B.

The third light source 133, which is located a distance d2 away from the first light source 131, is covered at the front by a first compensation plate 341 having a thickness t1 and a second compensation plate 342 having a thickness t4. The relationship between the distance from the center of this third light source 133 and the thickness of the compensation plate 340 that covers the front is the same as the relationship between the distance from the center of the second light source 32 and the thickness of the compensation plate 40 shown in Figures 5A and 5B.

Furthermore, the fourth light source 134, which is located at a distance d3 from the first light source 131, is covered at the front by a first compensation plate 341 having a thickness t1, a second compensation plate 342 having a thickness t4, and a third compensation plate 343 having a thickness t5. The relationship between the distance from the center of this fourth light source 134 and the thickness of the compensation plate 340 that covers the front is the same as the relationship between the distance from the center of the second light source 32 and the thickness of the compensation plate 40 shown in Figures 6A and 6B.

In this way, by using a correction plate 340 whose thickness increases in a stepped manner from the center to the outside, a correction plate having a thickness according to the distance from the center can be placed in front of the light source. This makes it possible to change the focusing position in the direction of travel for light from light sources placed further outwards, which is more susceptible to the effects of aberration, by using a thick correction plate. The effects are as described above.

In the above embodiment, a lighting device having a light source arranged on an optical axis OA and multiple light sources surrounding it has been described, but the technology disclosed herein can also be used for lighting devices having other arrangements of light sources.

(Embodiment 5)
Next, the illumination device 400 according to the fifth embodiment will be described with reference to Figs. 11A and 11B. As shown in Fig. 11A, the circuit board 425 has no light source arranged on the optical axis OA (the center of the illumination device 400) or on the circle 26, while a plurality of first light sources 431 arranged on the circumference of a circle 27 centered on the optical axis OA and one second light source 432 arranged on the circumference of a circle 28 centered on the optical axis OA. The radii of the circle 26, the circle 27, and the circle 28 are as described with reference to Fig. 4B and the like. That is, the circuit board 425 has a plurality of first light sources 431 arranged at equal positions from the optical axis OA, and one second light source 432 arranged outside the first light source 431.

The correction plate 440 is made of acrylic resin with a thickness t5 and is formed in a rectangular shape when viewed from the front. The correction plate 440 is fixed via bolts 42 provided at two adjacent corners of the four corners of the circuit board 425, and overlaps the second light source 432 on the front side, but does not overlap the first light source 431.

When illumination is performed using the illumination device 400, the light from the first light source 431 on the inside is adjusted to be focused on the illumination surface. In this case, the light from the second light source 432, which is farther from the optical axis OA than the first light source 431, is affected by aberration and becomes blurred. For this reason, a correction plate 440 is placed in front of the second light source 432 on the outside, which makes it possible to change the focusing position relative to the traveling direction of the light from the second light source 432.

(Embodiment 6)
Next, the illumination device 500 according to the sixth embodiment will be described with reference to Figs. 12A and 12B. As shown in Fig. 12A, the circuit board 525 has no light source arranged on the optical axis OA (the center of the illumination device 500) or on the circle 26, while one first light source 531 arranged on the circumference of a circle 27 centered on the optical axis OA and a plurality of second light sources 532 arranged on the circumference of a circle 28 centered on the optical axis OA. The radii of the circle 26, the circle 27, and the circle 28 are as described with reference to Fig. 4B and the like. That is, the circuit board 525 has a plurality of second light sources 532 arranged at equal positions from the optical axis OA, and one first light source 531 arranged inside the plurality of second light sources 532.

The correction plate 540 is made of acrylic resin and has a rectangular shape with a thickness of t5. The correction plate 540 is fixed to the circuit board 525 via bolts 42 provided at the four corners, with spacers 41 interposed between them. A circular opening 540a, for example with a diameter D4, is formed in the center of the correction plate 540. As a result, when viewed from the front, the front of the multiple second light sources 532 is covered by the correction plate 540, while the first light source 531 is exposed from the opening 540a and is not covered by the correction plate 540.

When illumination is performed using the illumination device 500, the light from the first light source 531 on the inside is adjusted to be focused on the illumination surface. In this case, the light from the second light source 532, which is farther from the optical axis OA than the first light source 531, is affected by aberration and becomes blurred. For this reason, a correction plate 540 is placed in front of the second light source 532 on the outside, which makes it possible to change the focusing position relative to the traveling direction of the light from the second light source 532.

(Seventh embodiment)
Next, the illumination device 600 according to the seventh embodiment will be described with reference to Figs. 13A, 13B, and 13C. In the above-mentioned embodiment, a plurality of light sources are arranged on the circumference of a circle centered on the optical axis OA. In the present embodiment, however, as shown in Fig. 13A, a plurality of light sources are arranged on the four sides of a square 680 whose center coincides with the optical axis OA, and the arrangement of the light sources is different from that of the above-mentioned embodiment. The circuit board 625 is provided with first light sources 631 arranged at the centers of the four sides of the square 680, second light sources 632 arranged on both sides of the first light source 631 at positions sandwiching the first light source 631, and third light sources 633 arranged at the four corners of the square 680. That is, the circuit board 625 is provided with four first light sources 631, eight second light sources 632, and four third light sources 633. Of these light sources, the first light source 631 is closest to the optical axis OA, the second light source 632 is next closest to the optical axis OA, and the third light source 633 is the furthest from the optical axis OA.

The correction plate 640 is formed of an acrylic resin plate with a rectangular opening 640a in the center. The correction plate 640 is fixed to the circuit board 625 via bolts 42 provided at the four corners with spacers 41 interposed therebetween. As shown in Figures 13B and 13C, the correction plate 640 has a first region 641 that covers the front of the first light source 631 and changes the focusing position relative to the traveling direction of the light from the first light source 631, a second region 642 that covers the front of the second light source 632 and changes the focusing position relative to the traveling direction of the light from the second light source 632, and a third region 643 that covers the front of the third light source 633 and changes the focusing position relative to the traveling direction of the light from the third light source 633. As shown in Figure 13A, each region is a rectangular region with a different thickness. As shown in Figures 13B and 13C, the thickness t6 of the first region 641 corresponding to the first light source 631 closest to the optical axis OA is the smallest among the thicknesses of the correction plate 640. The thickness t7 of the second region 642 corresponding to the second light source 632, which is next closest to the optical axis OA, is greater than the thickness t6. The thickness t8 of the third region 643 corresponding to the third light source 633, which is the furthest from the optical axis OA, is greater than the thickness t7. In this way, the correction plate 640 has regions of different thicknesses arranged along the four sides of a square whose center coincides with the optical axis OA. The thickness of the correction plate 640 is made greater in the regions corresponding to light sources farther away from the optical axis OA. This allows the focus position in the traveling direction to be changed by the thick correction plate for light from light sources located further out, which is more susceptible to the effects of aberration. The effect is as described above.

(Embodiment 8)
Next, a lighting device 700 according to an eighth embodiment will be described. In this embodiment, a plurality of light sources are arranged on a line passing through the optical axis OA, and the arrangement of the light sources is different from that in the above-mentioned embodiments in which the light sources are arranged on a circle or a square surrounding the optical axis OA. Specifically, the circuit board 725 has eleven light sources 731 arranged in a row on a line passing through the optical axis OA, as shown in FIG. 14A.

The correction plate 740 is formed from an acrylic resin plate with a rectangular opening 740a in the center. The correction plate 740 is fixed to the circuit board 725 via bolts 42 provided at the four corners, with spacers 41 interposed. The opening 740a of the correction plate 740 is formed to be large enough to open the front of the five first light sources 731a that are close to the optical axis OA among the eleven light sources 731. As a result, the correction plate 740 covers the front of three light sources on each end, that is, a total of six second light sources 731b. As a result, the light from the five first light sources 731a that are close to the optical axis OA is emitted from the lighting device 700 without passing through the correction plate 740, while the light from the six second light sources 731b that are far from the optical axis OA is emitted from the lighting device 700 after passing through the correction plate 740. This allows the light from a light source located further out, which is more susceptible to aberration, to be focused in the direction of travel by using a thick correction plate.

(Embodiment 9)
Next, a lighting device 800 according to a ninth embodiment will be described. As shown in Fig. 15A, the circuit board 825 has 15 light sources 831 arranged in a row on a line passing through the optical axis OA. The circuit board 825 in this embodiment has more light sources arranged on it than the circuit board in the eighth embodiment described with reference to Figs. 14A and 14B, and as a result, the light sources arranged at the ends of the multiple light sources 831 are located farther away from the optical axis OA.

As shown in FIG. 15A, the correction plate 840 has a rectangular opening 840a in the center. This opening 840a is formed to be large enough to open the front of the five first light sources 831a that are close to the optical axis OA among the 15 light sources 831. This makes it possible to prevent light from the first light sources 831a from entering the correction plate 840. In the correction plate 840, at a position adjacent to the opening 840a in the direction in which the multiple light sources 831 are arranged (the left-right direction in FIG. 15A), plate

thickness increasing portions

841 and 842 whose plate thickness increases linearly are arranged. The plate

thickness increasing portions

841 and 842 are arranged on both sides of the opening 840a, and when cut along a cross-sectional line along the direction in which the multiple light sources 831 are arranged, they have a right-angled triangular cross-sectional shape as shown in FIG. 15B. In addition, the plate

thickness increasing portions

841 and 842 have a thickness t9 sufficient to allow light from the second light source 831b to enter as shown in FIG. 15A. Each of the plate

thickness increasing portions

841 and 842 is arranged so that the plate thickness increases linearly with the

oblique sides

841a and 842a facing diagonally upward toward the outside of the lighting device. That is, the plate

thickness increasing portions

841 and 842 are arranged so that the

oblique sides

841a and 842a face each other across the opening 840a. The

oblique sides

841a and 842a form an angle θ1 with respect to the correction plate 840.

In this way, in the multiple light sources 831 arranged in a line, the front of the second light source 831b located away from the optical axis OA can be covered with the plate

thickness increasing portions

841, 842 whose plate thickness increases linearly outward. By forming the plate

thickness increasing portions

841, 842 whose plate thickness increases linearly outward from the optical axis OA in this way, a correction plate having a thickness according to the distance from the optical axis OA can be placed in front of the light source. This makes it possible to change the focusing position in the traveling direction for light from light sources located further outward from the optical axis OA, which is susceptible to the effects of aberration.

In the ninth embodiment, the effect of providing the correction plate 840 on the illumination light was verified. Specifically, the light from the first light source 831a on the optical axis OA was set to be focused on the irradiation surface, and then the correction plate 840 was inserted to verify what difference it made to the focusing state of the illumination light.

In addition, a Fresnel lens and a linear Fresnel lens were used in the lighting device to emit illumination light in a line shape as shown in Figures 16A and 16B, and the effect of the presence or absence of a correction plate 840 was verified. The grooves of the linear Fresnel lens were provided to extend in the left-right direction in Figure 15A.

When there is no correction plate 840, the ends of the linear illumination light 831' are not focused, resulting in blurring, as shown in FIG. 16A. On the other hand, when there is a correction plate 840, the ends of the illumination light 831' are focused, as shown in FIG. 16B, and it can be seen that the blurring has been improved.

(Embodiment 10)
Next, the illumination device 900 according to the tenth embodiment will be described with reference to Figs. 17A and 17B. As shown in Fig. 17A, the circuit board 925 is provided with one first light source 931 arranged on the optical axis OA (the center of the illumination device 900), a plurality of second light sources 932 arranged on the circumference of a circle 27 centered on the optical axis OA, and one third light source 933 arranged on the circumference of a circle 28 centered on the optical axis OA. The third light source 933 is provided, for example, at a position to the left of the optical axis OA when the sides of the rectangular circuit board 925 are arranged so as to be parallel to the up, down, left, and right directions in Fig. 17A. On the other hand, no light source is arranged on the circumference of the circle 26. The radii of the circle 26, the circle 27, and the circle 28 are as described with reference to Fig. 4B and the like. That is, a first light source 931 is arranged on the optical axis OA, a plurality of second light sources 932 are arranged at equal positions from the optical axis OA, and one third light source 933 is arranged outside the second light source 932 .

As shown in FIG. 17B, the correction plate 940 has a first correction plate 941 formed in a rectangular shape with a thickness t2, and a second correction plate 942 with a thickness t5 overlapped on the first correction plate 941 from the front side. A circular opening 940a is formed in the center of the first correction plate 941. The diameter of this opening 940a is smaller than the diameter of the circle 27 on which the multiple second light sources 932 are arranged, as shown in FIG. 17A. As a result, the first correction plate 941 opens the front of the first light source 931 through the opening 940a, while covering the front of the second light source 932 and the third light source 933. The second correction plate 942 is formed in a rectangular shape when viewed from the front, and is overlapped with one long side coinciding with one side of the first correction plate 941. The second correction plate 942 is fixed via bolts 42 provided at two adjacent corners of the four corners of the circuit board 925, and covers the front of the third light source 933 while not overlapping the first light source 931 or the second light source 932.

The illumination device 900 is adjusted so that light from the first light source 931 on the optical axis OA is focused on the irradiation surface. In this case, the light from the second light source 932 and the third light source 933, which are positioned further away from the optical axis OA, is affected by aberration and becomes blurred. For this reason, the thickness of the forward correction plate 940 is made thicker for light sources that are farther away from the optical axis OA, and the front of the second light source 932 is covered by the first correction plate 941, and the front of the third light source 933 is covered by the first correction plate 941 and the second correction plate 942.

(Embodiment 11)
Next, the illumination device 1000 according to the eleventh embodiment will be described with reference to FIG. 18A and FIG. 18B. As shown in FIG. 18A, the circuit board 1025 is provided with nine first light sources 1031 arranged in a cross shape in the up, down, left and right directions in the figure centered on the optical axis OA (the center of the illumination device 1000), and a plurality of second light sources 1032 arranged on the circumference of a circle 28 centered on the optical axis OA. Of the nine first light sources 1031, one is on the optical axis OA, and the remaining are arranged two by two on the up, down, left and right sides of the optical axis OA. On the other hand, no light source is arranged on the circumference of the circle 26 and the circle 27. That is, a plurality of second light sources 1032 are arranged at equal positions from the optical axis OA, and a plurality of first light sources 1031 in a cross shape are arranged inside the second light source 1032. A light source smaller than the second light source 1032 is used for the first light source 1031. Here, a small light source refers to a light source that is physically small, for example, a light source with a small light-emitting surface. In other words, the size of the light emitting surface of the first light source 1031 is smaller than the size of the light emitting surface of the second light source 1032 .

The correction plate 1040 is formed in a rectangular shape and has a thickness t3 as shown in FIG. 18B. A circular opening 1040a having a diameter D5, for example, is formed in the center of the correction plate 1040. The diameter D5 is set to a value smaller than the diameter of the circle 28 on which the multiple second light sources 1032 are arranged as shown in FIG. 18A, but larger than the diameter D3 of the opening 40a of the correction plate 40 shown in FIG. 6B, which has the same thickness t3. This makes it possible to prevent light from the first light sources 1031 arranged in a cross shape from entering the correction plate 1040. The correction plate 1040 covers the front of the second light source 1032.

The illumination device 1000 is adjusted so that the light from the first light source 1031 is focused on the irradiation surface. In this case, the light from the second light source 1032, which is positioned away from the optical axis OA, is affected by aberration and becomes blurred. For this reason, the front of the second light source 1032 is covered with a correction plate 1040. On the other hand, the first light source 1031 is less susceptible to aberration because it is a small light source and is positioned in a compact range centered on the optical axis OA. For this reason, the first light source 1031 is not covered by a correction plate and is left open in front.

(Embodiment 12)
Next, a lighting device 1100 according to embodiment 12 will be described with reference to Fig. 19A and Fig. 19B. As shown in Fig. 19A, a circuit board 1125 is provided with one first light source 1131 arranged on the optical axis OA (the center of the lighting device 1100) and a plurality of second light sources 1132 arranged on the circumference of a circle 27 centered on the optical axis OA. On the other hand, no light source is arranged on the circumference of the circle 26 and the circle 28. Note that a light source smaller than the second light source 1132 is used as the first light source 1131.

The correction plate 1140 is formed in a rectangular shape and has a thickness t2 as shown in FIG. 19B. A circular opening 1140a having a diameter D6, for example, is formed in the center of the correction plate 1140. The diameter D6 is smaller than the diameter D2 of the opening 40a of the correction plate 40 shown in FIG. 5B, which has the same thickness t2. Because a small light source is used as the first light source 1131, even if the diameter D6 is made small, it is possible to make it difficult for light from the first light source 1131 to be incident on the correction plate 1140. The correction plate 1140 covers the front of the second light source 1132.

The illumination device 1100 is adjusted so that the light from the first light source 1131 on the optical axis OA is focused on the irradiation surface. In this case, the light from the second light source 1132, which is positioned away from the optical axis OA, is affected by aberration and becomes blurred. For this reason, the front of the second light source 1132 is covered with a correction plate 1140.

This invention is not limited to the above embodiment, and various modifications and applications are possible. In the above embodiment, the condenser lens was described as a Fresnel lens, but the type of condenser lens is not particularly limited, and the technology of this disclosure can be applied even when a convex lens is used. As another example, a linear Fresnel lens is used to irradiate a line of illumination light, but in this case, the type of lens is not limited, and the technology of this disclosure can be applied even when a lens that has the function of spreading light in one dimension, such as a cylindrical lens or a lenticular lens, is used.

Although the correction plate has been described as being made of acrylic resin, the material can be selected from among other translucent materials that transmit light. For example, the material for the correction plate can be selected from transparent resins such as polycarbonate and polystyrene resin, or glass.

In addition, while it has been described that the correction plate 340 according to the fourth embodiment shown in FIG. 10B is formed by stacking the first correction plate 341, the second correction plate 342, and the third correction plate 343, the method of manufacturing the correction plate 340 is not particularly limited. For example, the correction plate 340 may be formed by cutting the

openings

341a, 342a, and 343a out of an acrylic resin plate having a thickness t3. The correction plate 940 according to the tenth embodiment shown in FIG. 17A and FIG. 17B may also be formed by processing an acrylic resin plate having a thickness t3.

In the lighting device according to embodiment 5 shown in Figs. 11A and 11B, the second light source 432 is covered with the rectangular correction plate 440, but the shape of the correction plate and the method of fixing the correction plate are not particularly limited. For example, the circuit board may be covered with a correction plate having a circular opening in the center that exposes the front of the first light source 431, and the four corners may be fixed with bolts 42.

Furthermore, in the seventh embodiment described with reference to Figures 13A to 13C, it has been described that multiple light sources are arranged on the four sides of a square 680 whose center coincides with the optical axis OA. However, the light sources may be arranged on the sides of another quadrangle, for example, multiple light sources may be arranged on the four sides of a rectangle. In this case, too, the thickness of the correction plate covering the front can be set appropriately depending on the distance from the optical axis OA to each light source. Furthermore, in the seventh embodiment, a light source may be arranged on the optical axis OA. Note that, because an opening 640a is formed in the correction plate 640, it is possible to prevent light from a light source arranged above the light source OA from entering the correction plate 640.

In addition, in the first embodiment, as shown in FIG. 4A and FIG. 4B, the first light source 31 is disposed on the optical axis OA, but it may be disposed near the optical axis OA instead of on the optical axis OA. In addition, the technology disclosed herein can be applied as long as the first light source 31 is disposed closer to the optical axis OA than the second light source 32. In that case, the light from the first light source 31 is adjusted so that it can be focused on the irradiation surface, and a correction plate that covers the front of the second light source 32 is disposed. In other embodiments, the first light source may also be disposed at a position off the optical axis OA. In this way, the first light source is closer to the optical axis OA than the second light source, and is a light source that does not require a correction plate. In other words, the first light source can be said to be a light source that is not affected by the correction plate. On the other hand, the second light source is disposed at a position farther from the optical axis OA than the first light source, and is a light source that requires a correction plate. Therefore, the second light source can be said to be a light source that has a correction plate disposed in front of it and is affected by the correction plate.

The number of first light sources and second light sources arranged on the circuit board is not particularly limited and can be set arbitrarily. It may be increased or decreased depending on the size of the lighting device. The first light sources and second light sources do not need to be arranged at equal intervals or at equal angles, and they may be spaced closer together in some areas and spaced apart in other areas. The colors of the first light sources and second light sources are arbitrary, and light sources of the same color may be used for the first light source and the second light source, or light sources of different colors may be used. The second light source may include light sources of multiple colors. In this way, the color of at least some of the second light sources may be different from the color of the first light source.

In the lighting device according to embodiment 8 shown in Figs. 14A and 14B, for example, two rectangular correction plates may be arranged so that their longitudinal directions coincide with the vertical direction in Fig. 14A and cover the second light sources 731b at each end. In this case, the two correction plates can be fixed to the circuit board 725 with bolts 42 arranged vertically in Fig. 14A.

In addition, in the lighting device according to embodiment 11 shown in Figs. 18A and 18B, a part of the first light sources 1031 arranged in a cross shape may be covered with a correction plate. As a mode of covering with a correction plate, for example, as shown in Fig. 14B, the first light sources 1031 that are a certain distance or more away from the optical axis OA may be covered with a correction plate of a certain thickness, or as shown in Fig. 15B, the first light sources 1031 that are a certain distance or more away from the optical axis OA may be covered with a correction plate whose thickness increases linearly.

Furthermore, the configuration in which the first light source is smaller than the other light sources as described in the eleventh and twelfth embodiments, and the configuration in which the first light source consisting of small light sources is arranged in a cross shape, may be applied to other embodiments.

Next, an example of how the lighting device can be used will be described. As an example, a case where the lighting device 100 (FIGS. 8A and 8B) according to the above-mentioned second embodiment is attached to a crane will be described. As shown in FIG. 20, an overhead crane 2000 will be used as an example of the crane to which the lighting device 100 can be attached, but the type of crane to which the lighting device 100 can be attached is not limited. In FIG. 20, the overhead crane 2000, the

loads

2005 and 2006 hoisted and carried by the overhead crane 2000, and the lighting device 100 are shown with two-dot chain lines to clearly illustrate the light that is irradiated to the ground. Also, a portion of the girder 2003 has been omitted in the length direction, and the vicinity of the load of the overhead crane 2000 is shown enlarged.

The overhead crane 2000 is equipped with running

rails

2001, 2002 that are installed in parallel inside a building such as a factory, a girder 2003 that is stretched across the running

rails

2001, 2002 and runs on the running

rails

2001, 2002, and a trolley 2004 that runs on the girder 2003 and carries a suspended load. The overhead crane 2000 hoists a variety of loads of different sizes. As an example, FIG. 20 illustrates a first load 2005 and a second load 2006 that is larger than the first load 2005 that are hoisted by the overhead crane 2000.

The lighting device 100 is attached to the trolley 2004. The lighting device 100 is installed with the emission surface facing downwards in order to irradiate light onto the ground. Since the lighting device 100 is mounted on the trolley 2004, the relative positional relationship between the

loads

2005, 2006 hoisted by the trolley 2004 and the lighting device 100 does not change even when the girder 2003 and the trolley 2004 are moving. The light emitted from the lighting device 100 generates a light pattern on the ground 2020. Here, the ground 2020 includes places where people can walk, such as the ground or the floor of a building. The light emitted from the lighting device 100 displays on the ground 2020 a load position indicator light 131' indicating the positions of the

loads

2005 and 2006, a plurality of first evacuation range indicator lights 132' indicating the range in which one must not enter when suspending the first load 2005, a plurality of second evacuation range indicator lights 133' indicating the range in which one must not enter when suspending the second load 2006, and four direction indicator lights 134' indicating the direction.

The load position display light 131' indicates that the centers of the

loads

2005 and 2006 are located above it. The load position display light 131' is generated by light emitted from the first light source 131 of the lighting device 100 shown in FIG. 8A.

The multiple first evacuation range display lights 132' are emitted in a circular pattern and are generated by light emitted from the second light source 132 of the lighting device 100 shown in FIG. 8A. By displaying the multiple first evacuation range display lights 132', it is possible to warn people not to enter an area where the first load 2005 may fall.

The multiple second evacuation range display lights 133' are emitted in a circular pattern and are generated by light emitted from the third light source 133 of the lighting device 100 shown in FIG. 8A. By displaying the multiple first evacuation range display lights 133', it is possible to warn people not to enter an area where the second load 2006 may fall. Note that since the second load 2006 is larger than the first load 2005, the area enclosed by the multiple second evacuation range display lights 133' is also larger than the area enclosed by the multiple first evacuation range display lights 132'.

The four direction display lights 134' are displayed at equal angular intervals of 90 degrees around the hanging position display light 131'. For example, the direction display light 134' displayed at the top of the figure is displayed at "north" of the hanging position display light 131', and the direction of "north" can be recognized by blinking only this display light. The four direction display lights 134' are generated by light emitted from four fourth light sources 134 arranged at the top, bottom, left and right in the figure, among the fourth light sources 134 of the display device shown in FIG. 8A. In this way, when indicating the direction using the fourth light source 134 shown in FIG. 8A, only the four fourth light sources 134 are arranged in the lighting device 100, or only the four fourth light sources 134 are turned on or blinked. Then, the direction of "north" can be recognized by blinking the light source displaying the direction of "north" to change the display method with other light sources, or by changing the color of the light source displaying "north" from the color of the other light sources.

Figure 20 illustrates all possible light patterns, but in reality, different light patterns may be generated depending on the situation. Also, the lighting device may have only the light sources necessary to generate the light pattern to be displayed.

For example, to transport the first load 2005 using the ceiling crane 2000, it is sufficient to display the load position indicator light 131' and the multiple first evacuation range indicator lights 132' on the ground. In this case, the light sources that emit the light are the first light source 131 and the second light source 132 shown in FIG. 8A. If the lighting device is used to transport only the first load 2005, it may have only the first light source 131 and the second light source 132. In this case, the color of some or all of the light sources of the second light source 132 may be different from the color of the first light source 131. Furthermore, if four direction indicator lights 134' are further displayed as a pattern to be displayed on the ground, the lighting device may further have four light sources of the fourth light source 134 shown in FIG. 8A, which are located above, below, left, and right. In such a lighting device, the second light source 132 and the fourth light source 134 arranged around the first light source 131 arranged on the optical axis OA may be described as the second light source.

For example, to transport the second load 2006 using the ceiling crane 2000, it is sufficient to display the load position indicator light 131' and the multiple second evacuation range indicator lights 133' on the ground. In this case, the light sources that emit light are the first light source 131 and the third light source 133 shown in FIG. 8A. If the lighting device is used to transport only the second load 2006, it is sufficient to have only the first light source 131 and the third light source 133. In this case, the third light source 133 arranged around the first light source 131 arranged on the optical axis OA may be described as the second light source. Note that the color of some or all of the second light sources may be different from the color of the first light source 131. Furthermore, when displaying four direction indicator lights 134 as a pattern to be displayed on the ground, the lighting device may further have four light sources of the fourth light source 134 shown in FIG. 8A, which are the top, bottom, left, and right. In such an illumination device, the third light source 133 and the fourth light source 134 arranged around the first light source 131 arranged on the optical axis OA may be described as the second light source.

For example, to transport the first load 2005 and the second load 2006 with the overhead crane 2000, it is necessary to display multiple first evacuation range display lights 132' or multiple second evacuation range display lights 133' on the ground depending on the type of load. In this case, the lighting device only needs to have the first light source 131, the second light source 132, and the third light source 133, and the second light source 132 and the third light source 133 arranged around the first light source 131 arranged on the optical axis OA may be described as the second light source.

In addition, instead of displaying the load position display light 131', a plurality of first evacuation range display lights 132' and a plurality of second evacuation range display lights 133' may be displayed to warn people not to enter depending on the type of load. In this case, the light source that emits the light is the second light source 132 and the third light source 133 shown in FIG. 8A, and a lighting device having only these light sources may be used. In this case, the second light source 132 arranged near the optical axis OA may be described as the first light source, and the third light source 133 arranged around it may be described as the second light source.

In this way, it is arbitrary to select which of the various display lights shown in FIG. 20 to display and how to combine them. The color of the light source can also be set arbitrarily. Furthermore, the display mode can be selected arbitrarily, such as turning on the light, blinking slowly, blinking quickly, etc. In this way, the mode of light emission from the light source can be set arbitrarily.

Furthermore, while it has been explained that the four direction indication lights 134' are generated by light emitted from the four fourth light sources 134 arranged in the top, bottom, left and right directions in the figure among the fourth light sources 134 of the display device shown in FIG. 8A, the direction indication light may also be displayed by the second light source 132 and the third light source 133, which have light sources arranged in the top, bottom, left and right directions in the figure.

In addition, the lighting device 1100 according to the above-mentioned embodiment 12 uses a light source for the first light source 1131 that is smaller than the other light sources, so when the device is attached to a crane, the emitted light that indicates the center of the suspended load is small. Therefore, the center position of the suspended load can be clearly and easily indicated.

In addition, the lighting device 1000 according to the above-mentioned embodiment 11 has a small light source that indicates the center of the suspended load, and further light sources are arranged above, below, to the left and right of the small light source to form a cross. This makes it possible to indicate the center position of the suspended load more clearly and easily.

The thickness of the correction plate in each of the above embodiments is based only on the distance from the optical axis OA of the light source covering the front, and for convenience, the same symbol (for example, thickness t3) is used if the distance is the same. Naturally, if various conditions differ, the optimal thickness of the correction plate will also differ, and the correction plate is set to an appropriate thickness based on the various conditions.

This disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of the disclosure. Furthermore, the above-described embodiments are intended to explain the disclosure and do not limit the scope of the disclosure. In other words, the scope of the disclosure is indicated by the claims, not the embodiments. Furthermore, various modifications made within the scope of the claims and the meaning of equivalent disclosures are deemed to be within the scope of the disclosure.

This application is based on Japanese Patent Application No. 2022-165779, filed on October 14, 2022. The entire specification, claims, and drawings of Japanese Patent Application No. 2022-165779 are incorporated herein by reference.

1...lighting device, 10...base portion, 20...main body portion, 21...case, 22...protective cover, 23...storage space, 24...condensing lens, 25...circuit board, 26, 27, 28...circle, 30...light source, 31...first light source, 32, 32a, 32b, 32b'...second light source, 40...correction plate, 40a...opening, 41...spacer, 42...bolt, 50...wall, 51, 52, 53...illumination light, 100...lighting device, 125...circuit board, 131...first light source, 131'...suspended load position indicator light, 132...second light source, 132'...first evacuation range indicator light, 133...third light source, 133'...second evacuation range indicator light 133', 134...fourth light source, 134'...direction indicator light, 140...correction plate, 140a...recess, 20 0...illumination device, 240...correction plate, 240a...dent, 300...illumination device, 340...correction plate, 341...first correction plate, 341a, 342a, 343a...opening, 342...second correction plate, 343...third correction plate, 400...illumination device, 425...circuit board, 431...first light source, 432...second light source, 440...correction plate, 500...illumination device, 525...circuit board, 531...first light source, 532...second light source, 540...correction plate, 540a...opening, 600...illumination device, 625...circuit board, 631...first light source, 632...second light source, 633...third light source, 640...correction plate, 640a...opening, 641...first region, 642...second region, 643...third region, 680...square, 700...illumination device 7, 800, 825, 831, 831′, 831′-840, 840a, 841, 841b, 841c, 841d, 841e, 841f, 841g, 841h, 841i, 841j, 841j, 841i, 841j, 841a, 841b ... 42...plate thickness increasing portion, 842a...oblique side, 900...illumination device, 925...circuit board, 931...first light source, 932...second light source, 933...third light source, 940...correction plate, 940a...opening, 941...first correction plate, 942...second correction plate, 1000...illumination device, 1025...circuit board, 1031...first light source, 1032...second light source, 1040...correction plate Main plate, 1040a...opening, 1100...lighting device, 1125...circuit board, 1131...first light source, 1132...second light source, 1140...correction plate, 1140a...opening, 2000...ceiling crane, 2001, 2002...traveling rail, 2003...girder, 2004...trolley, 2005...first suspended load, 2006...second suspended load, 2020...ground, θ1...angle, D1, D2, D3, D4, D5, D6...diameter, L1, L1', L2, L2', L3, L3', L4', L4', L5, L5', L6, L6', L7', L7a, L7b, L7c, L7c'...ray, O...origin, OA...optical axis, d1, d2, d3...distance, t1, t2, t3, t4, t5, t6, t7, t8...thickness

Claims

A plurality of light sources provided on substantially the same plane;
a condenser lens that condenses the light emitted from the plurality of light sources;
a correction plate that is interposed between at least some of the light sources and the condensing lens and changes a condensing position with respect to a traveling direction of the light emitted from the at least some of the light sources,
Lighting equipment.
the plurality of light sources include a first light source and a second light source provided on an outer side of the first light source with respect to an optical axis of the condenser lens,
The correction plate is interposed between the second light source and the condenser lens.
10. The lighting device of claim 1.
the first light source includes a light source provided on or near the optical axis of the condenser lens;
The second light source includes a plurality of light sources surrounding the first light source.
3. The lighting device according to claim 2.
The second light source is disposed on a circumference of a circle centered on the optical axis of the condenser lens.
4. The lighting device according to claim 3.
the second light source is disposed on a circumference of a plurality of circles having different diameters centered on the optical axis of the condenser lens,
The correction plate has a thickness that changes depending on the distance from the optical axis of the condenser lens.
4. The lighting device according to claim 3.
The second light source is disposed on four sides of a rectangle whose center coincides with the optical axis of the condenser lens,
The correction plate has a thickness that changes depending on the distance from the optical axis of the condenser lens.
4. The lighting device according to claim 3.
At least a part of the second light sources has a different color from the first light source.
3. The lighting device according to claim 2.
The first light source is a light source smaller than the second light source.
3. The lighting device according to claim 2.
The first light source is provided in plurality and arranged in a cross shape.
9. The lighting device according to claim 8.
the plurality of light sources are arranged on four sides of a rectangle whose center coincides with the optical axis of the condenser lens,
The correction plate has a thickness that changes depending on the distance from the optical axis of the condenser lens.
10. The lighting device of claim 1.
The correction plate has a thickness that increases linearly as the distance from the optical axis of the condenser lens increases.
11. An illumination device according to claim 5, 6 or 10.
The correction plate has a thickness that increases in a curved manner as the distance from the optical axis of the condenser lens increases.
11. An illumination device according to claim 5, 6 or 10.
The correction plate has a thickness that increases stepwise as the distance from the optical axis of the condenser lens increases.
11. An illumination device according to claim 5, 6 or 10.
It is attached to a crane and shines light onto the ground to display light patterns.
The light emitted from the first light source indicates a position of a load suspended by the crane,
The light emitted from the second light source indicates a retreat range from the suspended load.
The lighting device according to any one of claims 2 to 9.
It is attached to a crane and projects light onto the ground to display light patterns.
The light emitted from the first light source indicates a first evacuation range from the load of the crane,
The light emitted from the second light source indicates a second retraction range that is larger than the first retraction range.
The lighting device according to any one of claims 2 to 9.
It is attached to a crane and shines light onto the ground to display light patterns.
The light emitted from the first light source indicates at least one of a position of a load suspended by the crane and a retreat range from the load,
The light emitted from the second light source indicates a direction.
The lighting device according to any one of claims 2 to 9.
It is attached to a crane and shines light onto the ground to display light patterns.
The light emitted from the first light source indicates at least one of a position of a load suspended by the crane and a retreat range from the load,
The light emitted from the second light source indicates at least one of a retreat range and a direction from the suspended load,
The emission modes of the light from the first light source and the second light source can be controlled.
The lighting device according to any one of claims 2 to 9.