Road surface marking device

Abstract

Provided is a road surface rendering device that illuminates a road surface with a road surface rendering pattern (P1, P2). The road surface rendering device has a light source (5) and an optical component that causes the road surface to be illuminated with light emitted from the light source (5). The road surface rendering pattern (P1, P2) is shaped so as to be elongated in the direction away from the road surface rendering device. The optical component polarizes the light emitted from the light source (5) such that the illuminance at the edges of the road surface rendering pattern (P1, P2) is greater than the illuminance at the center thereof in a direction (D2) perpendicular to the lengthwise direction (D1) of the road surface rendering pattern (P1, P2).

Description

[Technical Field]

[0001] The present disclosure relates to a road surface drawing device. [Background technology]

[0002] Countries around the world are currently considering equipping vehicles with road surface drawing devices configured to project road surface drawing patterns onto the road surface around the vehicle in order to provide pedestrians and others around the vehicle with information indicating the vehicle's operation (for example, information indicating whether the vehicle is turning left, right, or reversing) (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 067113 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since road surface patterns are often drawn below the line of sight of people, road surface patterns drawn on the road surface are easily overlooked by pedestrians, etc. For this reason, there is a need to improve the visibility of road surface patterns.

[0005] An object of the present disclosure is to provide a road surface drawing device capable of forming a road surface drawing pattern that is more easily visible. [Means for solving the problem]

[0006] In order to achieve the above object, a road surface drawing device according to one aspect of the present invention comprises: A road surface drawing device that projects a road surface drawing pattern onto a road surface, A light source and an optical component that irradiates the road surface with light emitted from the light source, the road surface drawing pattern has an elongated shape extending in a direction away from the road surface drawing device, The optical component polarizes the light emitted from the light source in a direction perpendicular to the longitudinal direction of the road surface marking pattern so that the illuminance at the edge of the road surface marking pattern is higher than the illuminance at its center.

[0007] According to the above configuration, the illuminance of the edge of the road surface drawing pattern drawn on the road surface is higher than the illuminance of the center of the road surface drawing pattern, making the road surface drawing pattern easier to see than, for example, a case in which the illuminance of the edge and the illuminance of the center are about the same. In this way, the road surface drawing device according to the above configuration can form a road surface drawing pattern that is easier to see. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a road surface drawing device capable of forming a road surface drawing pattern that is more easily visible. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view of a vehicle equipped with a road surface drawing device according to this embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the road surface drawing device according to this embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of how light emitted from a light source is reflected by a reflector. [Figure 4] FIG. 4 is a diagram illustrating an example of the illuminance distribution of a road surface drawing pattern drawn by the road surface drawing device according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present disclosure (hereinafter referred to as the present embodiment) will be described with reference to the drawings. For the sake of convenience, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0011] Furthermore, in the description of this embodiment, for the sake of convenience, the terms "left-right direction," "up-down direction," and "front-rear direction" may be referred to as appropriate. These directions are relative directions set for the vehicle 100 shown in FIG. 1. Here, the "left-right direction" is a direction that includes the "left direction" and the "right direction," and is also the width direction of the vehicle 100. The "up-down direction" is a direction that includes the "upward direction" and the "downward direction." The "front-rear direction" is a direction that includes the "forward direction" and the "rearward direction." The front-rear direction is a direction that is perpendicular to the left-right direction and the up-down direction.

[0012] First, with reference to Fig. 1, a vehicle 100 equipped with a vehicle lamp 1 (an example of a road surface drawing device, hereinafter also referred to as "lamp 1") according to this embodiment will be described below. Fig. 1 is a plan view of a vehicle 100 equipped with a vehicle lamp 1 according to this embodiment. The vehicle 100 is, for example, a vehicle (automobile) that can run in a manual driving mode or an automatic driving mode. The lamp 1 projects light onto the road surface to draw an image (road surface drawing pattern) indicating predetermined information on the road surface.

[0013] The lamp 1 is mounted, for example, in headlights mounted on the left and right sides of the front of the vehicle 100. However, the location and configuration of the lamp 1 are not particularly limited. For example, the lamp 1 may be mounted in a tail light or a back light mounted on the rear of the vehicle 100. The lamp 1 may be mounted independently on the vehicle 100. Furthermore, for example, the lamp 1 may be disposed on the roof 100A.

[0014] The lamp 1 is configured to draw information indicating the operation of the vehicle 100 on the road surface. The information indicating the operation of the vehicle 100 may be, for example, information regarding the traveling direction of the vehicle. For example, when a decision is made to turn left for the vehicle 100, the lamp 1 projects a road surface drawing pattern P1 onto the road surface on the left side in front of the vehicle 100 to indicate to the outside that the vehicle 100 will turn left. For example, when a decision is made to turn right for the vehicle 100, the lamp 1 projects a road surface drawing pattern P2 onto the road surface on the right side in front of the vehicle 100 to indicate to the outside that the vehicle 100 will turn right. The road surface drawing patterns P1 and P2 are elongated in a direction away from the lamp 1 and have a substantially rectangular shape. For ease of explanation, in this embodiment, the longitudinal direction of the road surface drawing patterns P1 and P2 is referred to as direction D1, and the direction perpendicular to direction D1 is referred to as direction D2. The drawing method of the lamp 1 is not particularly limited; for example, a projection method or a scanning method may be adopted.

[0015] Next, the lighting fixture 1 will be described in detail with reference to Fig. 2. As illustrated in Fig. 2, the lighting fixture 1 comprises a lamp body 2 having an opening at the front of the lighting fixture, and a light-transmitting outer cover 3 that covers the opening of the lamp body 2. A light source 5, an optical unit 6 including at least one optical component, and an illumination control unit 7 are housed within a lamp chamber 4 formed by the lamp body 2 and the outer cover 3.

[0016] The light source 5 is configured, for example, by an LED (Light Emitting Diode) element or an LD (Laser Diode) element. The light source 5 may also be configured by a semiconductor light emitting element that emits laser light. The light source 5 is mounted on a substrate 50. The substrate 50 can be formed, for example, from a glass material such as silica glass, borosilicate glass, or alkali-free borosilicate glass, or a resin material such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, or cycloolefin polymer.

[0017] The optical unit 6 includes a reflector 61 and a lens 62. The reflector 61 is configured to reflect light emitted from the light source 5 toward the lens 62. The reflector 61 is disposed on the optical axis LA of the lens 62. The reflector 61 may be configured, for example, by a MEMS (Micro Electro Mechanical Systems) mirror. However, the reflector 61 may also be configured by a DMD (Digital Mirror Device), a blade mirror, or the like. However, the optical unit 6 is not limited to the above configuration as long as it is an optical system that can partially change the illuminance of the road surface drawing patterns P1, P2. The optical unit 6 may also include, for example, an LCD, an LCOS, a μLED, or the like.

[0018] The lens 62 is an aspherical lens with a convex front surface and a flat rear surface. The lens 62 is made of a light-transmitting material such as a transparent resin such as acrylic. The lens 62 is configured to project light emitted from the light source 5 forward of the lamp 1.

[0019] The lighting control unit 7 is configured to control the light source 5 and the reflector 61 so that the road surface drawing patterns P1 and P2 are projected onto the road surface around the vehicle 100. The lighting control unit 7 includes a microcontroller and an analog drive control circuit. The microcontroller has a processor such as a CPU and a memory such as a ROM. The analog drive control circuit includes a current control circuit configured to control the current supplied to the light source 5 and a mirror drive circuit configured to control the reflector 61. If the lamp 1 does not include the reflector 61, the analog drive control circuit is composed of the current control circuit. The location of the lighting control unit 7 is arbitrary and is not particularly limited. For example, the lighting control unit 7 may be provided outside the lamp 1.

[0020] Next, the reflector 61 will be described in detail with reference to Fig. 3. As illustrated in Fig. 3, the reflector 61 includes a plurality of micromirror elements 611. The plurality of micromirror elements 611 are arranged in an array (matrix). The reflector 61 can selectively change the reflection direction of light by controlling the angle of the reflective surface of each of the plurality of micromirror elements 611.

[0021] Light emitted from the light source 5 is irradiated onto the micro mirror elements 611 of the reflector 61. The reflector 61 reflects the irradiated light towards the lens 62 using the micro mirror elements 611. The light reflected by the micro mirror elements 611 passes through the lens 62 and is emitted in front of the lamp 1, and is irradiated onto areas selected according to the angle of the reflective surface of the micro mirror elements 611. As a result, road surface drawing patterns P1 and P2 are formed in front of the lamp 1.

[0022] Next, with reference to FIG. 4, the illuminance distribution of the road surface drawing pattern P1 drawn on the road surface around the vehicle 100 will be described. The illuminance distribution of the road surface drawing pattern P2 is similar to that of the road surface drawing pattern P1, and therefore only the illuminance distribution of the road surface drawing pattern P1 will be described in this specification. FIG. 4 is a diagram illustrating the illuminance distribution of the road surface drawing pattern P1 (see FIG. 1) in a direction D2 perpendicular to the longitudinal direction D1 of the road surface drawing pattern P1. FIG. 4 illustrates the illuminance distribution of the road surface drawing pattern P1 along the line segment X shown in FIG. 1. The dashed lines in FIG. 4 represent the illuminance distribution of a reference example road surface drawing pattern different from this embodiment, and the solid lines represent the illuminance distribution of the road surface drawing pattern P1 of this embodiment. For convenience of explanation, this embodiment will be described by dividing the road surface drawing pattern P1 equally into five regions, a first region A1 to a fifth region A5, in the direction D2. The first area A1 and the fifth area A5 correspond to the edges of the road surface marking pattern P1, and the second area A2 to the fourth area A4 correspond to the center of the road surface marking pattern P1.

[0023] As illustrated in FIG. 4, in the road surface marking pattern of the reference example, the illuminance in the second area A2 to the fourth area A4 (the central area of ​​the road surface marking pattern P1) is approximately the same as or higher than the illuminance in the first area A1 and the fifth area A5 (the edge areas of the road surface marking pattern P1). This is because, when light from a light source is projected forward through a projection lens without any special control, more light is projected onto the center of the projected area and less light is projected onto the edge areas. However, in this embodiment, the angle of the reflecting surface of the micromirror element 611 is set so that more light is distributed to the edge areas of the road surface marking patterns P1 and P2 than to the central areas. Therefore, more light emitted from the light source 5 is incident on the edge areas of the lens 62 than on the center area of ​​the lens 62. Specifically, in this embodiment, the angle of the reflecting surface of the micromirror element 611 of the reflector 61 is set so that part of the light normally irradiated onto the second region A2 to the fourth region A4 is irradiated onto the first region A1 and the fifth region A5. Therefore, the illuminance of the first region A1 and the fifth region A5 is higher than the illuminance of the second region A2 to the fourth region A4.

[0024] However, since road surface patterns are often drawn below the line of sight of people, road surface patterns drawn on the road surface are easily overlooked by pedestrians, etc. For this reason, there is a need to improve the visibility of road surface patterns.

[0025] With the vehicle lamp 1 having the above configuration, the illuminance of the edges (first area A1 and fifth area A5) of the road marking patterns P1, P2 drawn on the road surface is higher than the illuminance of the central areas (second area A2 to fourth area A4) of the road marking patterns P1, P2. Therefore, the road marking patterns P1, P2 drawn by the lamp 1 are easier to see than, for example, a case in which the illuminance of the edges of the road marking patterns is the same as the illuminance of the central area of ​​the road marking patterns. This is because the visibility of the road marking patterns can be improved by brightly illuminating the outlines (both ends in direction D2) of the road marking patterns, even if the interior is somewhat dark, rather than dimly illuminating the entire road marking pattern with a finite amount of light emitted from the light source.

[0026] In the road surface drawing pattern of this embodiment, the illuminance distribution in the second region A2 to the fourth region A4 is approximately uniform, whereas the illuminance distribution in the first region A1 and the fifth region A5 is non-uniform. Specifically, the illuminance distribution in the first region A1 and the fifth region A5 is higher near the center and lower near the edges. Therefore, the peak illuminance in the first region A1 and the fifth region A5 is higher than the peak illuminance in the second region A2 to the fourth region A4. In this embodiment, the illuminance in the first region A1 and the fifth region A5 is 1.5 times or more the illuminance in the second region A2 to the fourth region A4.

[0027] Furthermore, according to the vehicle lamp 1 having the above configuration, since the vehicle lamp 1 includes the optical unit 6, it is easy to polarize the light emitted from the light source 5 in a desired direction.

[0028] Furthermore, with the vehicle lamp 1 having the above configuration, the illuminance at the edges (first area A1 and fifth area A5) of the road surface marking patterns P1, P2 is at least 1.5 times that at the centers (second area A2 to fourth area A4) of the road surface marking patterns P1, P2. The greater the difference between the illuminance at the edges of the road surface marking patterns P1, P2 and the illuminance at the center of the road surface marking patterns P1, P2, the more likely pedestrians and others will notice the road surface marking patterns P1, P2. In other words, the more abrupt the change in illuminance within the road surface marking patterns P1, P2, the more likely pedestrians and others will notice the road surface marking patterns P1, P2. Therefore, the vehicle lamp 1 makes it possible for pedestrians and others to more easily recognize the road surface marking patterns P1, P2 without perceiving a decrease in the illuminance of the road surface marking patterns P1, P2.

[0029] Furthermore, with the vehicle lamp 1 having the above configuration, the illuminance in the first region A1 and the fifth region A5 is higher than the illuminance in the second region A2, the third region A3, and the fourth region A4, so the illuminance changes sharply within the road surface marking patterns P1 and P2. Therefore, the road surface marking patterns P1 and P2 drawn on the road surface by the vehicle lamp 1 having the above configuration have high visibility.

[0030] Although the embodiments of the present disclosure have been described above, it goes without saying that the technical scope of the present disclosure should not be interpreted as being limited by the description of the present embodiments. The present embodiments are merely examples, and it will be understood by those skilled in the art that various modifications of the embodiments are possible within the scope of the disclosure described in the claims. The technical scope of the present disclosure should be determined based on the scope of the disclosure described in the claims and its equivalents.

[0031] In the above embodiment, the lighting control unit 7 is separate from the vehicle control unit, but it may be configured integrally with the vehicle control unit.

[0032] In the above embodiment, the optical unit 6 includes the reflector 61 and the lens 62, but the optical unit 6 may include at least one of the reflector 61 and the lens 62. The optical unit 6 may also include a light guide in addition to or instead of these.

[0033] In the above-described embodiment, an example using the reflector 61 configured with a MEMS mirror has been described, but the present disclosure is not limited thereto. For example, the vehicle lamp 1 may have multiple light source units each including a reflector without a movable mirror and a light source. In this case, the orientation and shape of each reflector are set so that the number of light source units illuminating the edge region in the direction D2 is greater than the number of light source units illuminating the central region. Alternatively, the vehicle lamp 1 may have multiple light source units each including a reflector without a movable mirror, a light source, and a lens. In this case, the orientation and shape of each lens or reflector are set so that the number of light source units illuminating the edge region in the direction D2 is greater than the number of light source units illuminating the central region. Even with such a configuration, it is possible to polarize the light emitted from the light source so that the illuminance at the edge of the road surface drawing patterns P1, P2 is higher than the illuminance at the center thereof in the direction D2 perpendicular to the longitudinal direction D1 of the road surface drawing patterns P1, P2.

[0034] In the above embodiment, the road drawing patterns P1 and P2 are drawn on the road surface by the lighting fixture 1 projecting light onto the road surface, but the present disclosure is not limited to this. For example, the road drawing patterns P1 and P2 may be drawn on the road surface by a road drawing device provided on infrastructure equipment such as a street lamp, traffic light, or marker light projecting light onto the road surface.

[0035] This application is based on a Japanese patent application (Patent Application No. 2021-015770) filed on February 3, 2021, the contents of which are incorporated herein by reference.

Claims

1. A road surface drawing device that projects a road surface drawing pattern onto a road surface, A light source and an optical component that irradiates the road surface with light emitted from the light source, the road surface drawing pattern has an elongated shape extending in a direction away from the road surface drawing device, the optical component polarizes the light emitted from the light source in a direction perpendicular to the longitudinal direction of the road surface marking pattern so that the illuminance at the edge of the road surface marking pattern is higher than the illuminance at the center of the road surface marking pattern; a road surface drawing device, wherein when the road surface drawing pattern is equally divided into five regions, namely, a first region, a second region, a third region, a fourth region, and a fifth region, in a direction perpendicular to the longitudinal direction, the illuminance of the first region and the fifth region is higher than the illuminance of the second region, the third region, and the fourth region.

2. The road surface drawing device according to claim 1 , wherein the optical component includes at least one of a reflector, a lens, and a light guide.

3. 3. The road surface drawing device according to claim 1, wherein the illuminance of the edge portion is 1.5 times or more the illuminance of the center portion.

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