Lighting device

Abstract

To provide a lighting device that can improve light distribution performance.SOLUTION: A lighting device according to an embodiment comprises a light source and a lens. The lens is disposed on the output side of the light source. An entry surface through which light from the light source enters the lens has an S-shaped cross section in a plane defined by two axes defined by an exit direction of the light and a predetermined direction orthogonal to the exit direction.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE The present invention relates to a lighting device. [Background technology]

[0002] There are lighting devices that are mounted on agricultural and construction machinery and used as work lamps to assist in nighttime work. Lighting devices are mounted in various positions on the vehicle, such as the bottom or top of the vehicle, or on working equipment such as arms and booms, and emit light in a specific direction depending on the work content and purpose. For example, there are lighting devices that illuminate the worker's feet and the ground from the bottom of the vehicle, lighting devices that illuminate a wide area of ​​the work area from the top of the vehicle, and lighting devices that are mounted on a boom and directly illuminate the work area. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2015-531885 Summary of the Invention [Problem to be solved by the invention]

[0004] However, irradiation in a direction not intended by the worker can cause problems other than reducing illuminance in the required area. For example, light distribution toward the worker's face can be dazzling to the worker, obstructing his or her field of vision, or preventing eye contact between the driver and the worker, which can lead to concerns about reduced safety.

[0005] An object of the present invention is to provide an illumination device capable of improving light distribution performance. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, an illumination device according to one aspect of the present invention includes a light source and a lens. The lens is disposed on the emission side of the light source. An incident surface through which light from the light source enters the lens has an S-shaped cross section in a plane having two axes, the emission direction of the light and a predetermined direction perpendicular to the emission direction. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing the appearance of an illumination device 1 according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of a mounting position of the lighting device 1 according to the embodiment. [Diagram 3] FIG. 3 is a perspective view showing an example of the configuration of the lens 3 disposed inside the lighting device 1. As shown in FIG. [Figure 4] FIG. 4 is a perspective view showing an example of the configuration of the lens 3 disposed inside the lighting device 1. As shown in FIG. [Diagram 5] FIG. 5 is a cross-sectional view of the lens 3 taken along line XX in FIG. [Figure 6] FIG. 6 is an enlarged view of the entrance surface 3b and the exit surface 3c shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view of the lens 3 taken along the line Y-YX in FIG. [Figure 8] FIG. 8 is a diagram showing an example of a light ray image in the vertical direction. [Figure 9] FIG. 9 is a diagram showing an example of a light ray image in the horizontal direction. [Figure 10A] FIG. 10A is a cross-sectional view at X=−1 mm. [Figure 10B] FIG. 10B is a cross-sectional view at X=−2 mm. [Figure 10C] FIG. 10C is a cross-sectional view at X=−3 mm. [Figure 10D] FIG. 10D is a cross-sectional view at X=−4 mm. [Figure 10E] FIG. 10E is a cross-sectional view at X=−5 mm. [Figure 11]FIG. 11 is a cross-sectional view showing an example of the configuration of a lens 3' included in an illumination device 1' according to a comparative example. [Figure 12A] FIG. 12A is a diagram showing the light distribution by the lighting device 1. As shown in FIG. [Figure 12B] FIG. 12B is a diagram showing the light distribution caused by the lighting device 1'. [Figure 13] FIG. 13 is a comparison of the luminous intensity at X=0 in FIG. 12A and FIG. 12B. [Figure 14A] FIG. 14A is a diagram showing the difference in light distribution between the lighting device 1 and the lighting device 1′. [Figure 14B] FIG. 14B is a diagram showing the difference in light distribution between the lighting device 1 and the lighting device 1′. [Figure 15] FIG. 15 is a diagram showing a range in which an S-shape according to a modified example is formed. [Figure 16] FIG. 16 is a diagram showing a light distribution by the lighting device 1 according to the modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a lighting device according to an embodiment will be described with reference to the drawings. Note that the present invention is not limited to this embodiment. In addition, the dimensional relationship of each element in the drawings, the ratio of each element, etc. may differ from reality. Even between the drawings, there may be parts in which the dimensional relationship and ratio differ from each other. In addition, the contents described in one embodiment or modified example are, in principle, similarly applied to other embodiments or modified examples.

[0009] (Embodiment) 1 is a perspective view showing the appearance of an illumination device 1 according to an embodiment. For ease of explanation, the direction of irradiation of light from the illumination device 1 is described as the positive Z-axis direction, the horizontal direction when the illumination device 1 is in use is described as the X-axis direction, and the direction perpendicular to the irradiation direction and the horizontal direction (vertical direction) is described as the Y-axis direction.

[0010] 1, a cover lens 2, which also serves as an exterior, is disposed on the front of the lighting device 1. Inside the lighting device 1, in addition to lenses 3 and light sources 4 described below, substrates and wiring for supplying a driving current to the light sources 4 are appropriately disposed. The number of lenses 3 disposed inside the lighting device 1 may be one, or two or more.

[0011] FIG. 2 is a diagram showing an example of a mounting position of the lighting device 1 according to the embodiment. FIG. 2 illustrates a case where the lighting device 1 is mounted on a small-sized mini backhoe. Mounting positions A and B are located at the right front and left front of the upper rotating platform of the mini backhoe. At mounting positions A and B, the lighting device 1 is mounted so that the positive Y-axis direction corresponds to the upward direction of the mini backhoe. Mounting position C is located on the underside of the boom of the mini backhoe. At mounting position C, the lighting device 1 is mounted so that the positive Y-axis direction faces the opposite side to the main body in the longitudinal direction of the boom.

[0012] 3 and 4 are perspective views showing a configuration example of the lens 3 arranged inside the lighting device 1. Fig. 3 is a view seen from the exit surface 3c side of the lens 3, and Fig. 4 is a view seen from the entrance surface 3b side of the lens 3.

[0013] 3 and 4, the lens 3 has a flat portion 3a, an entrance surface 3b, and an exit surface 3c. The flat portion 3a is substantially plate-shaped and constitutes the outer periphery of the lens 3. Although not shown, the flat portion 3a is appropriately provided with screw holes and a concave-convex structure for fixing the lens 3 to the inside of the lighting device 1. The entrance surface 3b corresponds to the bottom surface of a recess formed on the entrance side (Z-axis negative direction side) of the flat portion 3a, and is formed by a free-form surface. One or more light sources 4 are disposed in the internal space formed by the recess, as described later. The exit surface 3c is formed by a free-form surface protruding on the exit side (Z-axis positive direction side) of the flat portion 3a, and has a convex shape.

[0014] Fig. 5 is a cross-sectional view of the lens 3 taken along the line XX in Fig. 3, and Fig. 6 is an enlarged view of the incident surface 3b and the exit surface 3c shown in Fig. 5. In Fig. 5, the light source 4 is disposed in the space inside the recess formed in the flat portion 3a. Note that the light source 4 does not necessarily have to be disposed in the space inside the recess as long as it is located in a position where it can irradiate the incident surface 3b. In other words, the lens 3 is disposed on the exit side of the light source 4. Also, the cover lens 2 is disposed on the exit side of the lens 3.

[0015] In FIG. 6, the cross section of the incident surface 3b in the YZ plane is an S-shape. The incident surface 3b has points P1, P2, P3, and P4 in a cross section in the YZ plane (the plane of X=0 when the center of the light source 4 is the origin). Point P1 is a point (first end point) corresponding to one end point in the cross section. Point P2 is a vertex (first vertex) below point P1. Point P3 is a vertex (second vertex) below point P2. Point P4 is a point (second end point) corresponding to the other end point in the cross section. When large and small are defined based on the distance from the center (origin) of the light source 4 in the Z-axis direction, point P2 is a minimum point, and point P3 is a maximum point.

[0016] That is, the S-shape of incident surface 3b is formed by a convex shape formed on the upper side (Y-axis positive direction side) of incident surface 3b in the cross section and a concave shape formed on the lower side (Y-axis negative direction side). Here, the convex shape is formed by a curved surface passing through points P1, P2, and P3, and the concave shape is formed by a curved surface passing through points P2, P3, and P4.

[0017] Specifically, point P2 is located closer to the light source 4 than point P3 in the Z-axis direction. Point P2 is located above the optical axis (dashed line in FIG. 6). In other words, point P2 is located between the optical axis and point P1 in the Y-axis direction.

[0018] Point P3 is below the optical axis. In other words, point P3 is between the optical axis and point P4 in the Y-axis direction. Point P4 is closer to the light source 4 than point P1 is in the Z-axis direction.

[0019] Furthermore, the exit surface 3c has a point P5 that corresponds to the apex of the convex shape of the exit surface 3c. The light source 4 (optical axis) is located above the point P5.

[0020] In addition, the cross-sectional shape of the incident surface 3b in the YZ plane can also be said to be a shape in which, compared to the overall concave shape, a convex shape having an apex (where the direction of inclination with respect to the optical axis changes) is partially provided in an area away from the optical axis of the light source 4 in the Y-axis direction.

[0021] Fig. 7 is a Y-YX cross-sectional view of the lens 3 in Fig. 3. In Fig. 7, the cover lens 2 has a lenticular lens with concave and convex grooves extending in the Y-axis direction on the entrance surface 2a onto which the light emitted from the lens 3 is incident.

[0022] Next, a description will be given of a light ray image formed by the lens 3 and the cover lens 2. Fig. 8 is a diagram showing an example of a light ray image in the vertical direction, and Fig. 9 is a diagram showing an example of a light ray image in the horizontal direction.

[0023] 8, of the light emitted from the light source 4, the light that enters the lens 3 above point P2 on the S-shaped entrance surface 3b is then totally reflected downward on the exit surface 3c, and is absorbed by the housing of the lighting device 1 (i.e., it is not emitted as illumination light). This allows the lens 3 to reduce the amount of light traveling upward (positive direction of the Y axis), that is, toward the face of the worker.

[0024] In Figure 9, light emitted from a light source 4 passes through a lens 3 and reaches a cover lens 2, where the horizontal light distribution is expanded by a lenticular lens provided on the entrance surface 2a of the cover lens 2, and the light is irradiated to the outside from the cover lens 2.

[0025] Here, the range (horizontal range) in which the S-shape of incident surface 3b is formed will be described. Fig. 10A is a cross-sectional view at X = -1 mm. Fig. 10B is a cross-sectional view at X = -2 mm. Fig. 10C is a cross-sectional view at X = -3 mm. Fig. 10D is a cross-sectional view at X = -4 mm. Fig. 10E is a cross-sectional view at X = -5 mm. Note that lens 3 is configured symmetrically in the horizontal direction. Therefore, the cross-sectional views at X = +1 to +5 mm are the same as Figs. 10A to 10E, respectively.

[0026] 10A to 10E, the S-shape of incident surface 3b is formed in the range from X=-2 to X=+2. That is, the S-shape is formed in the range including the center (X=0) of incident surface 3b in the horizontal direction. In other words, the S-shape is formed in the range of incident surface 3b in the horizontal direction where the amount of incident light is large.

[0027] Next, the light distribution performance of the lighting device 1 will be described in comparison with a lighting device 1' according to a comparative example. FIG. 11 is a cross-sectional view showing an example of the configuration of a lens 3' provided in the lighting device 1' according to the comparative example. An incident surface 3b' of the lens 3' is formed in a concave shape, not an S-shape. The exit surface 3c of the lens 3' has the same shape as the exit surface 3c of the lens 3. FIG. 11 also illustrates an example of a light image through the lens 3'.

[0028] Fig. 12A is a diagram showing the light distribution by the lighting device 1, and Fig. 12B is a diagram showing the light distribution by the lighting device 1'. It can be seen that in the light distribution by the lighting device 1' according to the comparative example (Fig. 12B), the light distribution at X=0 spreads slightly upward (in the positive direction of the Y axis) compared to the light distribution by the lighting device 1 (Fig. 12A).

[0029] Fig. 13 is a diagram comparing the luminous intensity at X=0 in Fig. 12A and Fig. 12B. The vertical axis of Fig. 13 corresponds to the luminous intensity [cd], and the horizontal axis corresponds to the angle [deg] in the Y-axis direction. In FIG. 13, as indicated by the dashed circle, it can be seen that the light distribution by the lighting device 1' according to the comparative example irradiates light in the range of 5 to 30 degrees.

[0030] 14A and 14B are diagrams showing the difference in light distribution between the lighting device 1 and the lighting device 1'. As shown in Fig. 14A, in the lighting device 1, light emitted from the light source 4 at an emission angle of 36° is refracted to 19.44° through the inner lens (incident surface 3b), and becomes -20.85° when emitted from the outer lens (exit surface 3c). On the other hand, as shown in Fig. 14B, in the lighting device 1' according to the comparative example, light also emitted from the light source 4 at an emission angle of 36° is refracted to 29.84° through the inner lens, and becomes 7.67° when emitted from the outer lens.

[0031] In this way, the lighting device 1 has reduced light distribution in the upward direction (positive direction of the Y axis) compared to the lighting device 1' according to the comparative example. This means that when the lighting device 1 is mounted at mounting position A or mounting position B, it is possible to reduce light directed toward the face of the worker. In other words, the lighting device 1 can improve its light distribution performance.

[0032] In addition, for example, the lighting device 1 can reduce the risk of obstructing the worker's visibility or interfering with eye contact between the driver and the worker by improving the light distribution performance, thereby preventing a decrease in safety.

[0033] (Modification) In the above embodiment, the S-shape is formed in the area of ​​the incident surface 3b in the horizontal direction where the amount of incident light is large, but this is not limited to this. For example, the S-shape may be formed in the entire area of ​​the incident surface 3b in the horizontal direction.

[0034] Fig. 15 is a diagram showing a range in which an S-shape according to a modified example is formed. In Fig. 15, the S-shape is formed on the entrance surface 3b within the entire range of X=-5 to +5 mm.

[0035] Fig. 16 is a diagram showing a light distribution by the lighting device 1 according to the modified example. Fig. 16 shows that the lighting device 1 according to the modified example can further suppress light distribution in the positive Y-axis direction. This allows the lighting device 1 according to the modified example to improve light distribution performance.

[0036] Although the embodiment and modifications of the present invention have been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0037] As described above, the lighting device according to the embodiment includes a light source and a lens disposed on the emission side of the light source, and the entrance surface of the lens through which the light from the light source enters has an S-shaped cross section in a plane (YZ plane) having two axes, the emission direction of the light and a predetermined direction perpendicular to the emission direction. This allows the lighting device to improve light distribution performance.

[0038] The S-shape is formed by a convex shape formed on one side (upper side) of the incident surface in the predetermined direction (Y-axis direction) and a concave shape formed on the other side (lower side), thereby making it possible to reduce light traveling in the predetermined direction.

[0039] The incident surface has a first end point (point P1) corresponding to one end point in the cross section, a second end point (point P4) corresponding to the other end point in the cross section, a first vertex (point P2) between the first end point and the second end point, and a second vertex (point P3) between the first vertex and the second end point, and the first vertex is located closer to the light source than the second vertex in the emission direction. This makes it possible to further reduce light traveling in a predetermined direction.

[0040] Moreover, the first apex is between the optical axis of the light source and the first end point in the predetermined direction, which makes it possible to further reduce the amount of light traveling in the predetermined direction.

[0041] Moreover, the second vertex is between the optical axis of the light source and the second end point in the predetermined direction, which makes it possible to increase the light distribution to the other side (lower side) in the predetermined direction.

[0042] Moreover, the second end point is located closer to the light source than the first end point in the emission direction, which makes it possible to increase the light distribution to the other side (lower side) in the predetermined direction.

[0043] The predetermined direction is a first direction, and the S-shape is formed in a range including the center of the incident surface in the emission direction and a second direction perpendicular to the first direction, thereby enabling efficient light distribution to areas with a large amount of light.

[0044] Further, the specified direction is a first direction, and the S-shape is formed in a range of the incident surface in a second direction perpendicular to the emission direction and the first direction where the amount of incident light is large, thereby enabling efficient distribution of light to areas where the amount of light is large.

[0045] The predetermined direction is a first direction, and the S-shape is formed over the entire area of ​​the incident surface in a second direction perpendicular to the emission direction and the first direction, thereby making it possible to further reduce light traveling in the predetermined direction.

[0046] In addition, the exit surface from which the light incident from the entrance surface exits has a convex shape, which makes it possible to increase the distribution of light to the other side (lower side) in the predetermined direction.

[0047] Moreover, the light source is located on one side of the apex of the convex shape in the predetermined direction, which makes it possible to increase the distribution of light toward the other side (lower side) in the predetermined direction.

[0048] The lens is a first lens, and further includes a second lens disposed on the exit side of the first lens, the second lens having a lenticular lens with concave and convex grooves extending in the predetermined direction on an entrance surface into which the light exiting from the first lens is incident. This makes it possible to widen the light distribution in the horizontal direction, and as a result, the horizontal size of the housing can be relatively reduced.

[0049] Moreover, the predetermined direction is a vertical direction of the lighting device, thereby making it possible to reduce the amount of light traveling upward.

[0050] Moreover, the lens distributes the light to one side in the predetermined direction in order to reduce the light distribution to the other side, thereby making it possible to reduce the light distribution to one side in the predetermined direction.

[0051] Furthermore, the present invention is not limited to the above-mentioned embodiment. The present invention also includes a configuration in which the above-mentioned components are appropriately combined. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-mentioned embodiment, and various modifications are possible. [Explanation of symbols]

[0052] 1 lighting device, 2 cover lens, 2a lenticular lens, 3 lens, 3a flat portion, 3b entrance surface, 3c exit surface, 4 light source

Claims

1. A light source; A lens disposed on the output side of the light source; Equipped with an incidence surface through which the light from the light source enters the lens has an S-shaped cross section in a plane having two axes, the emission direction of the light and a predetermined direction perpendicular to the emission direction; Lighting equipment.

2. The S-shape is formed by a convex shape formed on one side of the incident surface in the predetermined direction and a concave shape formed on the other side.

10. The lighting device of claim 1.

3. the incidence surface has a first end point corresponding to one end point in the cross section, a second end point corresponding to the other end point in the cross section, a first vertex between the first end point and the second end point, and a second vertex between the first vertex and the second end point; The first vertex is located closer to the light source in the emission direction than the second vertex.

10. The lighting device of claim 1.

4. the first vertex is between the optical axis of the light source and the first end point in the predetermined direction; 4. The lighting device according to claim 3.

5. the second vertex is between the optical axis of the light source and the second end point in the predetermined direction; 4. The lighting device according to claim 3.

6. The second end point is located closer to the light source in the emission direction than the first end point.

4. The lighting device according to claim 3.

7. the predetermined direction is a first direction, The S-shape is formed in a range including a center of the incident surface in a second direction perpendicular to the emission direction and the first direction.

10. The lighting device of claim 1.

8. the predetermined direction is a first direction, The S-shape is formed in a range of the incident surface in a second direction perpendicular to the emission direction and the first direction, where a light amount of the incident light is large.

10. The lighting device of claim 1.

9. the predetermined direction is a first direction, The S-shape is formed over the entire range of the incident surface in a second direction perpendicular to the emission direction and the first direction.

10. The lighting device of claim 1.

10. The exit surface from which the light incident from the entrance surface exits has a convex shape.

10. The lighting device of claim 1.

11. The light source is located on one side of the apex of the convex shape in the predetermined direction.

11. The lighting device of claim 10.

12. the lens is a first lens, Further comprising a second lens disposed on the exit side of the first lens, the second lens has a lenticular lens having concave and convex grooves extending in the predetermined direction on an incident surface onto which the light emitted from the first lens is incident; 10. The lighting device of claim 1.

13. The predetermined direction is a vertical direction of the lighting device.

10. The lighting device of claim 1.

14. The lens distributes the light to one side in the predetermined direction to reduce light distribution to the other side.

10. The lighting device of claim 1.

Images