Lighting fixture

Abstract

To provide a lighting fixture capable of suppressing upward emission of light without being restricted by a configuration in which a light source is arranged facing upward and a reflector is arranged above the light source.SOLUTION: A lighting fixture 10 comprises a light source unit that has a light-emitting element 23 and a lens 90, and emits light from the light-emitting element 23 through a lens 90 from a road surface emission opening 15. The light-emitting element 23 is arranged facing downward toward the road surface emission opening 15. The lens 90 has an incident surface 91 on which the light from the light-emitting element 23 is incident, a total reflection surface 100 that totally reflects light having passed through the incident surface 91, and a prism part 93 having a plurality of convex parts 94 that directs the light having been reflected by the total reflection surface 100 in a predetermined direction of a road 1.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a lighting fixture. [Background technology]

[0002] Low-position road lighting fixtures are known that are installed at a low position on the side of the road and have an emission opening on the road side. It is desirable for low-position road lighting fixtures to suppress upward emission of light, taking into consideration the impact on drivers of vehicles. Some lighting fixtures of this type suppress the upward emission of light by arranging a light source facing upward and reflecting the light from the light source downward using a road surface lighting reflector arranged above the light source (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-072241 Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the required optical characteristics, lighting performance and other regulations of the device, there may be cases where a configuration in which the light source is arranged facing upward and a reflector is arranged above the light source is not adopted. An object of the present invention is to provide a lighting device that can suppress light emitted upward without being restricted to a configuration in which a light source is arranged facing upward and a reflector is arranged above the light source. [Means for solving the problem]

[0005] In order to achieve the above-mentioned object, the present invention provides a lighting fixture that is installed at a low position beside a road and has an exit opening on the road side, the lighting fixture comprising a light source unit having a light-emitting element and a lens, and emitting light from the light-emitting element from the exit opening via the lens, the light-emitting element being arranged facing downward toward the exit opening, and the lens comprising an entrance surface on which the light from the light-emitting element is incident, a total reflection surface that totally reflects the light that has passed through the entrance surface, and a prism portion having a plurality of convex portions that direct the light reflected by the total reflection surface in a specified direction toward the road. Effect of the Invention

[0006] According to the present invention, it is possible to suppress light emitted upward without being restricted by a configuration in which a light source is disposed facing upward and a reflector is disposed above the light source. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing a low-position road lighting fixture according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram showing an example of a road on which lighting fixtures are installed. [Diagram 3] FIG. 1 is a block diagram showing a configuration of a lighting system. [Figure 4] FIG. 2 is a side view showing the light source unit together with the surrounding configuration. [Diagram 5] FIG. 2 is a perspective view showing a lens portion of the lens unit together with a light emitting element, viewed obliquely from above. [Figure 6] FIG. [Figure 7] 4 is a diagram showing the cross-sectional shape of the entrance surface together with the surrounding configuration. FIG. [Figure 8] 1A and 1B are diagrams showing the light path of a light-emitting element. [Figure 9] 1A to 1C are diagrams illustrating a procedure for designing a lens portion. [Figure 10] 13A shows the external shape before and after the addition of another reflecting surface, and FIG. 13B shows reflected light before and after the addition of another reflecting surface. [Figure 11] FIG. 2 is a diagram illustrating a lens unit. [Figure 12] 1A shows a top view of the lens unit, and FIG. 1B shows a side view of the lens unit. [Figure 13] FIG. 1A is a perspective view of a lens unit, and FIG. 1B is a diagram showing the path of light in the bb cross section of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a low position road lighting fixture 10 according to this embodiment. The low-position road lighting fixture 10 is a lighting fixture installed at a low position on the side of the road. The low-position road lighting fixture 10 is installed on the side of the road at an installation height (for example, approximately 1.0 to 1.2 meters) that is approximately the same as the line of sight of a driver of a vehicle traveling on the road 1, and illuminates the road 1 from that installation position. Hereinafter, the low-position road lighting fixture 10 will be referred to as "lighting fixture 10."

[0009] Fig. 2 shows an example of a road 1 on which a lighting fixture 10 is installed. The road 1 has a main line 1A with three lanes 1B on each side, and the direction of travel of vehicles on the main line 1A is indicated by the symbol F. The main line 1A is also called a carriageway. The road 1 is provided with a central divider 1C, a shoulder 1D, and a side line 1E. As shown in Fig. 2, the lighting fixtures 10 are installed at a predetermined wide span installation interval S (e.g., 20 m or more) along a road 1. The lighting fixtures 10 are configured to achieve a predetermined lighting performance when installed at a predetermined installation height and installation interval S. The lighting performance is specified by, for example, average vertical illuminance, overall vertical illuminance uniformity, and vertical illuminance lane axis uniformity, and is specified so as to satisfy conditions that can suppress glare for vehicle drivers, etc. (for example, conditions such as an elevation angle of a predetermined angle or more and a luminous intensity of a predetermined value or less).

[0010] This lighting fixture 10 employs a so-called pro-beam lighting system in which most light L is distributed in the vehicle's traveling direction F. However, it is not necessary to be limited to the pro-beam lighting system. For example, a symmetric lighting system with a so-called symmetric light distribution that illuminates in the vehicle's traveling direction F and the opposite direction may be employed, or a counter beam irradiation system that illuminates in the opposite direction to the vehicle's traveling direction F may be employed.

[0011] As shown in Fig. 1, the lighting fixture 10 has a rectangular parallelepiped fixture body 11 extending in the road travel direction X. The fixture body 11 has a main body case 12 with an opening on the front side corresponding to the road 1 side, and a front cover 13 that covers the front opening of the main body case 12, and houses an optical system and various components inside.

[0012] FIG. 3 is a functional block diagram of lighting fixture 10. Provided within the main body 11 of the lighting fixture 10 are a road surface light-emitting unit 21 that emits light to illuminate the main line 1A and the road shoulder 1D, a side line light-emitting unit 31 that outputs light to illuminate the side line 1E of the road surface, a visual guidance light-emitting unit 41 that outputs light that functions as a visual guidance light, a control device 51 that controls the turning on and off of each of the light-emitting units 21, 31, 41, and a reflector 55.

[0013] 1, an opening 14 for visual guidance (hereinafter referred to as visual guidance opening 14) is provided on a side of the main body case 12 that is visible to the driver. Light from the visual guidance light emitting unit 41 is emitted from the visual guidance opening 14 toward the driver of the vehicle. This allows the driver of the vehicle to see the light for visual guidance. The front cover 13 has a plurality of emission openings functioning as an opening 15 for road surface lighting (hereinafter referred to as road surface emission opening 15) and an opening 16 for side line lighting (hereinafter referred to as side line emission opening 16) on the road 1 side. The road surface emission opening 15 and the side line emission opening 16 may be the same opening.

[0014] Light from the road surface light emitting portion 21 is emitted from the road surface emission opening 15 toward the main line 1A and the road shoulder 1D of the road surface. As a result, the main line 1A and the road shoulder 1D are illuminated. In addition, light from the side line light emitting unit 31 is emitted from the side line emission opening 16 toward the side line 1E. This illuminates the side line 1E, making it easier for the driver to see the side line 1E. The side line 1E is a dividing line that divides the shoulder 1D and the side strip from the main line 1A, and is also called an outer line.

[0015] 3, the control device 51 includes a communication unit 52 and a control unit 53. The communication unit 52 includes a communication module and receives control information D1 transmitted from an external remote control device. The control unit 53 includes a processor, a memory, and peripheral circuits, and the processor operates according to a program stored in the memory to control turning on and off the light-emitting units 21, 31, and 41 based on the control information D1.

[0016] The reflector 55 is provided at a position offset along the road traveling direction X with respect to the light source unit 22 of the road surface light-emitting section 21, and reflects the light incident from the light source unit 22 and the light reflected by the transparent front cover 15c (see FIG. 4) provided on the road surface emission opening 15 toward the road 1. This reflector 55 improves the efficiency of light utilization of the light source unit 22, which is advantageous for improving the illuminance on the road 1.

[0017] Next, the light source unit 22 of the road surface light emitting portion 21 will be described. Fig. 4 is a side view of the light source unit 22 together with the surrounding configuration. Fig. 4 shows the device depth direction Y. The device depth direction Y is a direction that coincides with the road crossing direction of the lighting device 10 installed at the roadside. Note that the number of light source units 22 that the road surface light-emitting unit 21 has is an item that is appropriately set according to the specifications.

[0018] As shown in FIG. 4, the light source unit 22 has a light emitting element 23 and a lens 90, and emits light from the light emitting element 23 via the lens 90 from the road surface emission opening 15 which is an emission opening. The light emitting element 23 is an LED mounted on a substrate 23k, and is, for example, an SMD (Surface Mount Device) type LED. The light emitting element 23 may be a COB (Chip On Board) type or a light emitting element other than an LED.

[0019] An optical base plate 24 that supports the substrate 23k and the lens 90 is provided within the main body case 12. The light-emitting element 23 is supported by the optical base plate 24 facing downward toward the road surface emission opening 15. The lens 90 has a screw insertion portion 90s through which a screw can be inserted, and the screw insertion portion 90s is fixed to the optical base plate 24 by using a screw. The lens 90 is fixed to the optical base plate 24 by having a screw fastening structure or a known positioning structure. In this embodiment, the lens 90 is supported below the light-emitting element 23 and on the side of the road surface emission opening 15.

[0020] A light-shielding control plate 25 is provided around the road surface emission opening 15 to block the light emitted from the upper end and the lower end of the lens 90. The light-shielding control plate 25 is, for example, a plate member whose surface is painted in matte black. A wide range of known light-shielding members can be applied to the light-shielding control plate 25. Since the light emitted from the upper and lower ends of the lens 90 is a source of stray light, it is possible to suppress upward leakage light (which can also be called upward light flux) that may be caused by such stray light by blocking such light with the light blocking control plate 25. Since the upward leakage light is suppressed, it is possible to suppress glare for the driver.

[0021] 4, a transparent front cover 15c is disposed via a lamp front frame 15w over the emission opening for road surface 15. This transparent front cover 15c prevents rainwater from entering the emission opening for road surface 15, etc. As indicated by the symbol α in Fig. 4, the light source unit 22 includes a lens unit 90UT having two lenses 90 integrally formed therewith. There is a one-to-one relationship between the light emitting elements 23 and the lenses 90. The lens units 90UT are set in an appropriate number and layout according to the number and layout of the light emitting elements 23 included in the road surface light emitting section 21. Since the lens unit 90UT includes two lenses 90, this is advantageous for reducing the number of parts and improving ease of assembly.

[0022] 5 is a perspective view showing the lens portion of the lens unit 90UT from diagonally above together with the light emitting element 23. Each lens 90 includes a lens portion 92 having an incident surface 91 onto which the light from the light emitting element 23 is incident, and a prism portion 93 that directs the light from the lens portion 92 in a predetermined direction of the road 1 (a direction that realizes a pro beam in this embodiment), and each lens portion 92 has the same shape.

[0023] The upper surface of the lens unit 90UT is provided with a recessed portion 90k equivalent to a hollowed-out portion. The entire upper surface of the lens unit 90UT, except for the recessed portion 90k, is formed as a flat surface. The recessed portion 90k is provided in an area where the light of the light-emitting element 23 does not reach, and the weight of the lens can be reduced without affecting the optical characteristics. By forming the upper surface of the lens unit 90UT as a flat surface, the light directed upward within the lens 90 is totally reflected, and the upward leakage of light can be suppressed.

[0024] Each prism portion 93 is an optical lens formed by arranging a plurality of convex portions 94 in a direction corresponding to the road traveling direction X. Each convex portion 94 is formed in a triangular cross section having a reflecting surface that totally reflects the light from the lens portion 92 and an exit surface that emits the light reflected by the reflecting surface, and emits the light from the lens portion 92 in a predetermined direction of the road 1 (a direction that realizes a pro beam in this embodiment).

[0025] By configuring each prism portion 93 to have a plurality of convex portions 94, the depth of the prism portion 93 can be made smaller than when the prism portion 93 is configured with a single convex portion 94. This allows the longitudinal size of the lens unit 90UT to be reduced. The longitudinal direction of the lens unit 90UT corresponds to the device depth direction Y (FIG. 4). Therefore, by reducing the longitudinal size of the lens unit 90UT, the depth size of the lighting device 10 can be made more compact.

[0026] FIG. 6 is a diagram showing the lens portion 92 from above. The incident surface 91 of the lens portion 92 is formed in a concave shape by recessing one end in the longitudinal direction of the lens portion 92 toward the lower end in the longitudinal direction and downward. The lower surface of the lens portion 92 is formed into a total reflection surface 100 (FIG. 5) that totally reflects the light transmitted through the incident surface 91. Fig. 6 shows a virtual light source point P1. The virtual light source point P1 is a point that is on the emission side of the center of the light-emitting surface of the light-emitting element 23 and is not the light-emitting center of the light-emitting element 23 when viewed from the emission surface side. In this embodiment, the virtual light source point P1 is set near an end point of the light-emitting surface of the light-emitting element 23 when viewed from above the lens shown in Fig. 6.

[0027] Fig. 6 shows a light-emitting surface central vertical cross section Z1, which is a vertical cross section passing through the center of the light-emitting surface of the light-emitting element 23, and a virtual light source vertical cross section Z2, which is a vertical cross section passing through the virtual light source point P1. The virtual light source vertical cross section Z2 overlaps with the optical axis of the light-emitting element 23 when viewed from above the lens shown in Fig. 6. The virtual light source vertical cross section Z2 is parallel to the light-emitting surface central vertical cross section Z1.

[0028] FIG. 7 is a diagram showing the cross-sectional shape of the entrance surface 91 together with the surrounding configuration, and shows the cross-sectional shape on the virtual light source vertical cross section Z2. The incident surface 91 includes a spherical first incident surface 91a and a convex second incident surface 91b located outside the first incident surface 91a. Fig. 7 shows an optical axis L0' of a virtual light source point P1. The optical axis L0' of the virtual light source point P1 is an axis parallel to the optical axis of the light-emitting element 23, which is extended from the virtual light source point P1, and is located parallel to and close to the optical axis of the light-emitting element 23.

[0029] The first entrance surface 91a is formed as a spherical surface centered on the virtual light source point P1, and receives perpendicularly incident light from the light-emitting element 23. The first entrance surface 91a allows the light from the light-emitting element 23 to be incident while suppressing reflection. This first entrance surface 91a is formed in a region corresponding to at least the optical axis L0' of the virtual light source point P1, and is thereby formed in a region corresponding to the optical axis of the light-emitting element 23. Therefore, light with a large luminous flux (corresponding to "central light") out of the light from the light-emitting element 23 can be efficiently incident.

[0030] The second incident surface 91b is formed in a convex shape towards the light emitting element 23, so that light from the light emitting element 23 is refracted and incident thereon. The convex shape of the second incident surface 91b is a shape that directs the light reflected by the second incident surface 91b in a direction in which it is difficult for the light to re-enter the incident surface 91. Light that re-enters the incident surface 91 at a position away from the optical axis of the light emitting element 23 becomes a source of stray light, so by suppressing the re-entry of such light, it is possible to suppress upward leakage light (which can also be called upward light flux) that may be caused by such stray light.

[0031] Figure 7 shows, when viewed from the side of the lens, the angle θ1 from the lower limit position PL of the first incident surface 91a to the optical axis L0', the angle θ2 from the optical axis L0' to the upper limit position PU of the second incident surface 91b, the angle θ3 from the vertical position passing through the virtual light source point P1 to the optical axis L0', and the angle θ4 from the optical axis L0' to the upper limit position of the first incident surface 91a. The values ​​of the above angles θ1 to θ4 are set to appropriate numerical values ​​so that the first incident surface 91a is formed in an area corresponding to the optical axis of the light-emitting element 23, the second incident surface 91b suppresses the re-incursion of light that is a source of stray light, and the incident surface 91 consisting of the first incident surface 91a and the second incident surface 91b is within a range that sufficiently covers the light irradiation area of ​​the light-emitting element 23.

[0032] The area and shape of the first incident surface 91a may be appropriately changed within a range in which light from the light emitting element 23 can be sufficiently incident while suppressing reflection, for example, the first incident surface 91a may be formed into a concave shape approximating the above-mentioned spherical surface. The area and shape of the second incident surface 91b may also be appropriately changed within a range in which light re-entering the incident surface 91, which is a source of stray light, can be suppressed.

[0033] Fig. 8 is a diagram showing a cross-sectional shape in the longitudinal direction of the lens portion 92. More specifically, Fig. 8(A) and Fig. 8(B) each show the path of light from the light-emitting element 23 in the cross-sectional shape of the virtual light source vertical cross section Z2. As shown in Fig. 8(A) and Fig. 8(B), the total reflection surface 100 of the lens portion 92 includes a paraboloid 100a that reflects light incident on the incident surface 91 in parallel, and a straight portion 100b that reflects light transmitted through the incident surface 91 downward. The paraboloid 100a is formed as a paraboloid of revolution that totally reflects light from the light-emitting element 23 that has been transmitted from the virtual light source point P1 through the first incident surface 91a and entered the paraboloid 100a downward and in parallel. The light from the light-emitting element 23 is totally reflected downward and in parallel by the paraboloid 100a, so that it is possible to irradiate illumination light suitable for long-span road lighting while suppressing upward leakage of light.

[0034] 8(A) and 8(B) show the rotation axis Lr of the paraboloid 100a. The rotation axis Lr passes through the virtual light source point P1, and the further away from the virtual light source point P1, the lower the axis becomes. The rotation axis Lr is set as an axis inclined at an angle θr with respect to the horizontal plane. The rotation axis Lr is set on the virtual light source vertical cross section Z2. The vertical angle of the parallel light reflected by the parabolic surface 100a is set to a predetermined vertical angle (for example, a fixed value between 80° and 90°), and is hereinafter referred to as the “design vertical angle.” In other words, the lens unit 92 functions as a parallel light lens unit that emits parallel light at the design vertical angle.

[0035] The straight section 100b is a surface with a straight cross section that totally reflects downward the light that has passed through the second entrance surface 91b, and emits the light at an angle substantially the same as the above-mentioned designed vertical angle. More specifically, the straight line portion 100b is formed in a shape extending in the tangent direction of the paraboloid 100a at the boundary position between the paraboloid 100a and the straight line portion 100b. As a result, as shown in Fig. 8(B), the light incident from behind the virtual light source point P1 (corresponding to the left side of the virtual light source point P1 in Fig. 8(B)) is reflected slightly downward from the parallel light Ka reflected by the paraboloid 100a at the designed vertical angle, as shown by light Ka' in Fig. 8(B).

[0036] In this way, the parabolic surface 100a and the straight portion 100b reflect all the light passing through the incident surface 91 at the same angle as the design vertical angle and at an angle slightly downward from the design vertical angle. Therefore, it is possible to emit illumination light suitable for long-span road lighting, and light directed upward from the design vertical angle can be suppressed, which is also advantageous in suppressing glare to drivers.

[0037] The straight portion 100b in this configuration is provided at a position different from the parabolic surface 100a in the direction in which the optical axis of the light-emitting element 23 extends. Therefore, compared to the case in which the parabolic surface 100a is extended in the direction in which the optical axis of the light-emitting element 23 extends, the length of the total reflection surface 100 in the longitudinal direction can be reduced, and the light transmitted through the incident surface 91 can be output at the designed vertical angle or an angle close to the designed vertical angle. This allows the longitudinal size of the lens portion 92 to be reduced, while emitting illumination light suitable for long-span road lighting. By reducing the longitudinal size of the lens portion 92, it becomes easier to make the depth size of the lighting fixture 10 compact.

[0038] As described above, in this configuration, virtual light source point P1 is set on the output side from the center of the light emitting surface of light emitting element 23. Therefore, light that enters total reflection surface 100 from a position other than virtual light source point P1 can be efficiently reflected downward. This also makes it possible to suppress upward leakage of light, making it easier to suppress glare for the driver.

[0039] Lens 90 will now be further described with reference to FIGS. FIG. 9 is a diagram showing a design procedure for the lens portion 92. As shown in FIG. In the first step, a three-dimensional model of a rotating mirror having a total reflection surface 100 in which a paraboloid 100a and a straight portion 100b are rotated 180° around a rotation axis Lr is produced (FIG. 9(a)). This three-dimensional model of the rotating mirror also has an entrance surface 91 and a recessed portion 90k. In the second step, the three-dimensional model of the rotating mirror is cut in half with respect to the central vertical cross section Z1 of the light-emitting surface as a reference so that the opposite side of the virtual light source point P1 remains, to produce a cut model (FIG. 9b, c). In the third step, the cut model is mirrored on the opposite side with respect to the central vertical cross section Z1 of the light-emitting surface as a reference, to produce a three-dimensional model of the lens portion 92 (FIG. 9d, e).

[0040] In this way, the lens unit 92 has, as the paraboloid 100a of the total reflection surface 100, a first paraboloid of revolution 100a1 corresponding to the shape that exists on the opposite side of the virtual light source point P1 when a paraboloid of revolution with a focus at the virtual light source point P1 is cut at the central vertical cross section Z1 of the light-emitting surface, and a second paraboloid of revolution 100a2 corresponding to the shape obtained by mirroring the first paraboloid of revolution 100a1 on the opposite side with respect to the central vertical cross section Z1 of the light-emitting surface. This makes it possible to prevent the light incident on the parabolic surface 100a from a position other than the virtual light source point P1 from not being reflected downward. By preventing such a situation, it is possible to prevent the light from leaking upward, which makes it easier to prevent glare for the driver.

[0041] In this configuration, another reflecting surface 100a3 that reflects light more downward than other parts of the paraboloid 100a (corresponding to the first and second paraboloids of revolution 100a1, 100a2) is added to the three-dimensional model of the lens portion 92. Figure 10 is a diagram for explaining the other reflecting surface 100a3, where Figure 10(A) shows the external shape before and after the addition of the other reflecting surface 100a3, and Figure 10(B) shows the reflected light before and after the addition of the other reflecting surface 100a3.

[0042] As shown in Fig. 10(A), the other reflecting surface 100a3 is provided in the area Sa corresponding to the mating surface of the first paraboloid of revolution 100a1 and the second paraboloid of revolution 100a2 and the periphery thereof. Fig. 10(B) shows the reflected light Kd when the other reflecting surface 100a3 is not provided and the reflected light Kd' of the other reflecting surface 100a3 for the incident light Kc. The two-dot chain line in Fig. 10(B) shows the paraboloid (corresponding to the paraboloid of revolution 100a1, 100a2) when the other reflecting surface 100a3 is not provided.

[0043] In this configuration, a rotation axis is set downward from the rotation axis Lr (see FIG. 8), and a paraboloid of revolution rotated around this rotation axis is used as the other reflecting surface 100a3. Therefore, the other reflecting surface 100a3 can emit a substantially parallel reflected light Kd' downward from the reflected light Kd. The above-mentioned area Sa has a large amount of emitted light flux, and corresponds to an area where light is emitted far away in the road travel direction by the prism portion 93, so light that causes glare to the driver is likely to be generated. The other reflective surface 100a3 can suppress upward leakage of light from the area Sa, making it easier to suppress glare to the driver.

[0044] In this way, after producing a three-dimensional model of the lens portion 92 having the other reflecting surface 100a3, the lens portions 92 are connected side by side and a prism portion 93 is provided on each lens portion 92, as shown in Fig. 11, to produce a three-dimensional model of the lens unit 90UT. The lens unit 90UT is molded based on this three-dimensional model. In this embodiment, the case where the other reflecting surface 100a3 is provided in the region of the paraboloid 100a is illustrated, but the other reflecting surface 100a3 may be provided in either the region of the paraboloid 100a or the linear portion 100b. In addition, in cases where glare to the driver can be sufficiently suppressed, the other reflecting surface 100a3 may not be provided.

[0045] The prism portion 93 will be described with reference to FIGS. FIG. 12(A) shows a top view of the lens unit 90UT, and FIG. 12(B) shows a side view of the lens unit 90UT. 12(A), for each prism portion 93, a convex portion 94 (corresponding to a central convex portion 94c) located in a widthwise center region Sc of the lens unit 90UT is formed larger than the other convex portions 94. In other words, the central convex portion 94 is formed so that the area into which the light from the light emitting element 23 is incident is larger than the other convex portions 94.

[0046] This region Sc corresponds to a region where the emitted light flux from the lens portion 92 is large. Since the central convex portion 94c in the region Sc has a larger area on which the light from the light emitting element 23 is incident than the other convex portions 94, it is possible to suppress light leakage from the valley portions between the adjacent convex portions 94 when the central light having a large emitted luminous flux is emitted in a predetermined direction of the road 1. This suppresses glare for the driver and is advantageous for improving the illuminance and uniformity of the road 1.

[0047] In this configuration, both the prism height and width of the central convex portion 94c are greater than those of the other prism portions 93. Therefore, the central light having a larger emitted luminous flux can be efficiently emitted toward the traveling direction of the road 1. At least one of the prism height and width of the central convex portion 94c may be changed to a size similar to that of the other convex portions 94 or smaller, as long as the leakage of light from the prism portion 93 is sufficiently suppressed.

[0048] The other convex portions 94 are formed into an appropriate shape including their pitch and size. An appropriate shape may be any shape that can efficiently emit light in a direction that realizes a pro-beam, which is the emission direction toward the road 1. For example, it is preferable that the shape can reduce as much as possible the situation in which light is emitted in a direction other than the emission direction toward the road 1 due to the influence of the adjacent prism portion 93 or adjacent convex portions 94. Note that any two or more of the plurality of convex portions 94 may be formed in the same shape as long as the road 1 can be appropriately illuminated and leakage light can be sufficiently suppressed.

[0049] 12(B) shows range W (the reflecting surfaces and the exit surface of all of the convex portions 94) of the prism portion 93 in the side view of the lens. In this configuration, by making the entire range W have a shape that is inclined upward from the exit surface 92M of the lens portion 92, the light of the lens portion 92 can be directed more downward. The angle at which the prism portion 94 is tilted upward is, for example, in the range of 0 to 1.0°. This changes the light from the lens portion 92 at the designed vertical angle to light directed slightly downward and is emitted from the prism portion 93. This makes it possible to suppress upward leakage light, suppress glare for the driver, and emit light to a wide area including the distance in the road travel direction.

[0050] FIG. 13A is a perspective view showing lens unit 90UT from the prism portion 93 side, and FIG. 13B shows the light path of the bb cross section of prism portion 93 in FIG. 13A. As shown in Fig. 13(A), a part of the total reflection surface of the prism portion 93 is provided with an inclined surface 94d that changes the direction of light incident on the total reflection surface to a downward direction. The inclination angle of the inclined surface 94d is, for example, in the range of 0 to 1.0°. This allows the light reflected by the inclined surface 94d to be directed more downward than the light Ke reflected without the inclined surface 94d, as shown by light Ke' in Fig. 13(B).

[0051] In this embodiment, by providing an inclined surface 94d on part of the total reflection surface of the central convex portion 94c, light with a large luminous flux can be directed downward, making it easier to prevent light leaking upward. However, the convex portion 94 on which the inclined surface 94d is provided does not have to be limited to the central convex portion 94c. In short, it is sufficient to suppress the upward light by providing the inclined surface 94d in an area of ​​the multiple convex portions 94 where the light is likely to be emitted upward. It is also preferable to prevent the light from re-entering the adjacent convex portions 94 by adjusting the inclination angle, inclination direction, and range of the inclined surface 94d.

[0052] As described above, the lighting fixture 10 of this embodiment includes a light source unit 22 having a light emitting element 23 and a lens 90, and emitting light from the light emitting element 23 from the road surface emission opening 15 via the lens 90. As shown in Fig. 4, the light emitting element 23 is disposed facing downward toward the road surface emission opening 15, and the lens 90 includes an incident surface 91 on which the light from the light emitting element 23 is incident, a total reflection surface 100 that totally reflects the light that has passed through the incident surface 91, and a prism portion 93 having a plurality of convex portions 94 that direct the light reflected by the total reflection surface 100 in a predetermined direction of the road 1. According to this configuration, the light emitting element 23 is arranged facing downward, and the light incident on the lens 90 into which the light of the light emitting element 23 is incident is totally reflected, and the totally reflected light is emitted in a predetermined direction of the road 1, so that it is possible to suppress the light emitted upward and efficiently use the light incident on the lens 90 to illuminate the road 1 without being restricted by a configuration in which a light source such as a light emitting element is arranged facing upward and a reflector is arranged above the light source. Since the light emitted upward can be suppressed, it becomes easier to appropriately perform high-span road lighting while suppressing glare to drivers.

[0053] In addition, since a flat surface is provided on the upper surface of the lens 90, the light directed upward within the lens 90 is totally reflected, and upward leakage of light can be suppressed. This suppresses glare for the driver and makes it easier to make the lens 90 smaller.

[0054] Furthermore, the plurality of convex portions 94 reflect the light reflected by the total reflection surface 100 toward the traveling direction of the road. With this configuration, the light incident on the lens 90 can be efficiently utilized to provide pro-beam illumination of the road 1.

[0055] Furthermore, among the multiple convex portions 94, the central convex portion 94c has a larger area into which light from the light emitting element 23 is incident than the other convex portions 94. With this configuration, when the central light having a larger emitted luminous flux is emitted in a predetermined direction of the road 1, it is possible to suppress light leakage from the valley portions between the adjacent convex portions 94. This is advantageous for suppressing glare for the driver and improving the illuminance and uniformity of the road 1.

[0056] Moreover, at least the central convex portion 94c among the multiple convex portions 94 is provided with an inclined surface 94d that reflects incident light downward. According to this configuration, light with a large luminous flux that is incident on at least the central convex portion 94c can be emitted downward, and glare to the driver can be further reduced.

[0057] Further, the incident surface 91 has a spherical first incident surface 91a located in a region corresponding to the optical axis of the light-emitting element 23, and a second incident surface 91b located outside the first incident surface 91a and convex toward the light-emitting element 23. With this configuration, the first incident surface 91a efficiently allows light with a large luminous flux from the light-emitting element 23 to be incident, and the reflected light generated by the second incident surface 91b can be reflected in a direction in which it is difficult for the reflected light to re-enter the incident surface 91. As a result, it is possible to efficiently allow the light from the light-emitting element 23 to be incident, while suppressing upward leakage of light caused by light re-entering the incident surface 91.

[0058] Furthermore, a recess 90k equivalent to a hollowed-out portion is provided on the flat upper surface of the lens 90 in an area not reached by light from the light-emitting element 23. According to this configuration, the recess 90k makes the lens 90 thinner, and the moldability of the lens 90 can be improved.

[0059] Moreover, the total reflection surface 100 has a parabolic surface 100a that reflects the light transmitted through the incident surface 91 in parallel, and a straight portion 100b that reflects the light transmitted through the incident surface 91 downward, and the straight portion 100b is provided at a position different from the parabolic surface 100a in the direction in which the optical axis of the light-emitting element 23 extends. With this configuration, it is possible to reduce the length of the longitudinal direction of the total reflection surface 100 and suppress the upward leakage of light, compared to the case in which the parabolic surface 100a is extended in the direction in which the optical axis of the light-emitting element 23 extends. As a result, it is easy to reduce the glare to the driver, and it is easy to reduce the longitudinal size of the lens 90 and make the lighting device 10 compact.

[0060] Moreover, the total reflection surface 100 includes a first paraboloid of revolution 100a1 that corresponds to a shape that exists on the opposite side of the virtual light source point P1 when a paraboloid of revolution having a focal point at a virtual light source point P1 set at a predetermined position (corresponding to a position on the emission surface side and not the light emission center) with respect to the light emission center of the light emitting element 23 is cut along the light emission surface central vertical cross section Z1. Furthermore, the total reflection surface 100 includes a second paraboloid of revolution 100a2 that corresponds to a shape that mirrors the first paraboloid of revolution 100a1 on the opposite side based on the light emission surface central vertical cross section Z1. According to this configuration, it is possible to prevent a situation in which light that enters each of the paraboloids of revolution 100a1 and 100a2 from a position different from the virtual light source point P1 is not reflected downward, and it is easy to prevent light leaking upward. This makes it easier to prevent glare to the driver.

[0061] In addition, the position of the virtual light source point P1 does not have to be limited to a position on the exit surface side of the light-emitting center of the light-emitting element 23 and other than the light-emitting center, and may be changed appropriately within a range that prevents the light entering each of the revolution paraboloids 100a1, 100a2 from a position other than the virtual light source point P1 from being reflected downward.

[0062] Moreover, the total reflection surface 100 has a paraboloid 100a that reflects the light transmitted through the incident surface 91 in parallel, and a part of this paraboloid 100a has another reflection surface 100a3 that reflects the light more downward than the first and second paraboloids of revolution 100a1 and 100a2 that are the other parts of the paraboloid 100a. With this configuration, the other reflection surface 100a3 can further suppress the upward leakage of light, making it easier to suppress glare for the driver.

[0063] In addition, a reflector 55 is provided at a position offset from the light source unit 22 along the road travel direction X. According to this configuration, the reflector 55 improves the efficiency of light utilization of the light from the light source unit 22, which is advantageous for improving the illuminance of the road 1.

[0064] The above-described embodiment is merely an example of one embodiment of the present invention, and any modifications and applications are possible without departing from the spirit and scope of the present invention. For example, the configuration of the lighting device 10, the configuration of the light source unit 22, the shape of the lens 90, the configuration of the lens unit 90UT, etc. may be changed as appropriate. For example, the lens unit 90UT may be configured with three or more lenses 90 connected together, or may be configured with one lens 90.

[0065] The above embodiment supports the following configurations.

[0066] (Configuration 1) A lighting fixture that is installed at a low position beside a road and has an exit opening on the road side, the lighting fixture comprises a light source unit having a light-emitting element and a lens, and emitting light from the light-emitting element from the exit opening via the lens, the light-emitting element is arranged facing downward toward the exit opening, and the lens comprises an incident surface on which the light from the light-emitting element is incident, a total reflection surface that totally reflects light that has passed through the incident surface, and a prism portion having multiple convex portions that direct the light reflected by the total reflection surface in a specified direction toward the road. According to this configuration, it is possible to suppress light emitted upward without being restricted by a configuration in which a light source such as a light-emitting element is disposed facing upward and a reflector is disposed above the light source.

[0067] (Configuration 2) The lighting device according to configuration 1, wherein a flat surface is provided on an upper surface of the lens. According to this configuration, the light traveling upward inside the lens is totally reflected, and the upward leakage of light can be suppressed.

[0068] (Configuration 3) The lighting device according to configuration 1 or 2, wherein the plurality of convex portions reflect the light reflected by the total reflection surface toward a traveling direction of a road. According to this configuration, the light incident on the lens can be efficiently utilized to provide pro-beam illumination of the road.

[0069] (Configuration 4) The lighting device according to any one of configurations 1 to 3, wherein a central convex portion among the plurality of convex portions has a larger area onto which light from the light emitting element is incident than the other convex portions. According to this configuration, when the central light having a large emitted luminous flux is emitted in a predetermined direction of the road, leakage of light from valleys between adjacent convex portions can be suppressed.

[0070] (Configuration 5) The lighting device according to any one of configurations 1 to 4, wherein at least a central convex portion among the plurality of convex portions is provided with an inclined surface that reflects the incident light downward. According to this configuration, light with a large luminous flux that is incident on at least the central convex portion can be emitted downward, thereby further reducing glare to the driver.

[0071] (Configuration 6) A lighting device as described in any one of configurations 1 to 5, wherein the incident surface has a spherical first incident surface located in a region corresponding to the optical axis of the light-emitting element, and a second incident surface located outside the first incident surface and convex toward the light-emitting element. According to this configuration, light with a large luminous flux from the light emitting element can be efficiently incident on the first incident surface, and reflected light generated on the second incident surface can be reflected in a direction in which it is less likely to re-enter the incident surface.

[0072] (Configuration 7) The lighting device according to configuration 2, wherein the flat surface is provided with a hollowed-out portion in an area where light from the light-emitting element does not reach. According to this configuration, the recessed portion allows the lens to be made thinner, and the moldability of the lens can be improved.

[0073] (Configuration 8) A lighting device described in any one of configurations 1 to 7, wherein the total reflection surface has a parabolic surface that reflects light that has passed through the incident surface in a parallel manner, and a straight portion that reflects light that has passed through the incident surface downward, the straight portion being located at a position different from the parabolic surface in the direction in which the optical axis of the light-emitting element extends. With this configuration, compared to when the parabolic surface is extended in the direction of the optical axis of the light emitting element, it is possible to reduce the longitudinal length of the total reflection surface while suppressing upward leakage of light.

[0074] (Configuration 9) A lighting device described in any one of configurations 1 to 8, wherein the total reflection surface includes a first paraboloid of revolution corresponding to a shape that exists on the opposite side of a virtual light source point when a paraboloid of revolution having a focus at a virtual light source point set at a predetermined position with respect to the light-emitting center of the light-emitting element is cut along a vertical cross section passing through the light-emitting center of the light-emitting element, and a second paraboloid of revolution corresponding to a shape obtained by mirroring the first paraboloid of revolution on the opposite side with respect to the vertical cross section. According to this configuration, it is possible to prevent the situation in which light incident on each paraboloid of revolution from a position other than the virtual light source point is not reflected downward, and it becomes easier to prevent light leaking upward.

[0075] (Configuration 10) A lighting device described in any one of configurations 1 to 9, wherein the total reflection surface has a paraboloid that reflects light that has passed through the incident surface in a parallel manner, and a part of the paraboloid has another reflective surface that reflects light more downward than other parts of the paraboloid. According to this configuration, the other reflective surfaces can further reduce upward leakage of light, making it easier to reduce glare for the driver.

[0076] (Configuration 11) The lighting device according to any one of configurations 1 to 10, further comprising a reflector disposed at a position offset from the light source unit along the road travel direction. This configuration improves the efficiency of light utilization from the light source unit, which is advantageous for improving the illuminance of the road. [Explanation of symbols]

[0077] 1 road 1A Main Line 1D Shoulder 1E Outer Line 10 Low-position lighting equipment (lighting equipment) 12 Light source unit 15 Output aperture for road surface (output aperture) 21. Illumination unit for visual guidance 23 Light emitting element 31 Road surface light emitting unit 41 Light emitting part for lateral line 51 Control device 52 Communications Department 53 Control section 55 Reflector 90 Lens 90k Recessed part (hollowed out part) 90UT Lens Unit 91 Incidence plane 91a 1st entrance plane 91b 2nd entrance plane 93 Prism section 94 Convex 94c Central protrusion 100 total reflection surface 100a Paraboloid 100a1 First paraboloid of revolution 100a2 Second paraboloid of revolution 100a3 Other reflective surfaces 100b Straight section P1 Virtual light source point Z1 Vertical cross section of the center of the light-emitting surface Z2 Virtual light source vertical section

Claims

1. A lighting fixture that is installed at a low position on the side of a road and has an exit opening on the road side, a light source unit having a light emitting element and a lens, the light source unit emitting light from the light emitting element through the lens and from the emission opening; The light emitting element is disposed facing downward toward the light exit opening, The lens is an incidence surface on which light from the light-emitting element is incident; a total reflection surface that totally reflects light transmitted through the incident surface; a prism portion having a plurality of convex portions that directs the light reflected by the total reflection surface in a predetermined direction of the road. Lighting fixtures.

2. A flat surface is provided on the upper surface of the lens.

2. A lighting fixture according to claim 1.

3. The plurality of convex portions reflect the light reflected by the total reflection surface in the traveling direction of the road.

2. A lighting fixture according to claim 1.

4. Among the plurality of convex portions, a central convex portion has a larger area onto which light from the light emitting element is incident than the other convex portions.

2. A lighting fixture according to claim 1.

5. Among the plurality of protrusions, at least the central protrusion is provided with an inclined surface that reflects the incident light downward.

5. A lighting device according to claim 4.

6. The incident surface is a spherical first incident surface located in a region corresponding to the optical axis of the light emitting element; a second incident surface located outside the first incident surface and convex toward the light emitting element; 2. A lighting fixture according to claim 1.

7. The flat surface is provided with a hollowed-out portion in an area where the light of the light-emitting element does not reach.

3. A lighting device according to claim 2.

8. the total reflection surface being a paraboloid that reflects light transmitted through the incident surface in parallel; a linear portion that reflects downward the light that has passed through the incident surface, The linear portion is provided at a position different from the parabolic surface in a direction in which the optical axis of the light emitting element extends.

2. A lighting fixture according to claim 1.

9. The total reflection surface is a first paraboloid of revolution corresponding to a shape that exists on the opposite side of a virtual light source point when a paraboloid of revolution having a focus at a virtual light source point set at a predetermined position with respect to the light emission center of the light emitting element is cut along a vertical cross section passing through the light emission center of the light emitting element, and a second paraboloid of revolution corresponding to a shape obtained by mirroring the first paraboloid of revolution on the opposite side with respect to the vertical cross section.

2. A lighting fixture according to claim 1.

10. the total reflection surface has a parabolic surface that reflects the light transmitted through the incident surface in parallel, A part of the paraboloid has another reflective surface that reflects light more downward than the other part of the paraboloid.

2. A lighting fixture according to claim 1.

11. A reflector is provided at a position offset from the light source unit along the road travel direction.

2. A lighting fixture according to claim 1.

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