Road surface drawing device

Abstract

A road surface drawing device (1) comprises: an image forming light source (30) that emits light to form a predetermined drawing image (50); and a lens unit (40) that projects the drawing image (50) onto a road surface, wherein the lens unit (40) includes one convex meniscus lens (41) having an incident surface (42) that is curved in a convex shape and into which light is incident, and an emission surface (43) that is curved in a concave shape and from which light is emitted.

Description

road surface drawing device

[0001] The present invention relates to a road surface drawing device.

[0002] A vehicle may be equipped with a road surface drawing device that draws a predetermined image on a road surface. Patent Document 1 listed below discloses such a road surface drawing device. The road surface drawing device in Patent Document 1 listed below includes a light source and a projection lens that projects light from the light source onto the road surface. The projection lens is a plano-convex lens that has a flat incident surface onto which light from the light source enters and a convexly curved exit surface from which light from the light source exits.

[0003] Japanese Patent Application Laid-Open No. 2021-102409

[0004] In the road surface drawing device described in Patent Document 1, there is a demand for a clearer image drawn on the road surface. To meet this demand, for example, it is conceivable to project light using multiple lenses. However, this would increase the number of parts.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a road surface drawing device that can clearly draw an image on the road surface while suppressing an increase in the number of parts.

[0006] In order to achieve the above-mentioned object, the road surface drawing device of the present invention comprises an image forming light source that emits light that forms a predetermined drawing image, and a lens unit that projects the drawing image onto the road surface, characterized in that the lens unit consists of a single convex meniscus lens that is convexly curved and has an incident surface through which the light enters, and a concavely curved exit surface through which the light exits.

[0007] This road surface drawing device can suppress an increase in the number of parts compared to using multiple lenses. Furthermore, when a convex meniscus lens is used as the projection lens, spherical aberration tends to be smaller than when a plano-convex lens, which has a flat entrance surface and a convexly curved exit surface, is used as the projection lens. Therefore, this road surface drawing device can draw a clearer image on the road surface compared to when the lens unit is made of a plano-convex lens and light is incident on the flat side of the plano-convex lens.

[0008] The focal plane of the convex meniscus lens on the image-forming light source side may be positioned on an emission area of ​​the image-forming light source that emits the light.

[0009] With this configuration, the image drawn on the road surface can be made clearer.

[0010] The image forming light source may include a light emitting unit in which a plurality of light emitting sections capable of individually changing the amount of light emitted are arranged, and which emits light that forms the drawn image.

[0011] With this configuration, multiple still images and moving images can be rendered.

[0012] The image forming light source may include a light emitting section that emits light, and a shade that blocks a portion of the light emitted from the light emitting section so that the light emitted from the light emitting section becomes light that forms the drawn image.

[0013] As described above, according to the present invention, it is possible to provide a road surface drawing device that can clearly draw an image on the road surface while suppressing an increase in the number of parts.

[0014] FIG. 1 is a conceptual diagram showing a vehicle equipped with a road surface drawing device according to a first embodiment of the present invention, together with a drawn image drawn by the road surface drawing device. FIG. 2 is a perspective view schematically showing an image-forming light source and a lens unit in the first embodiment. FIG. 3 is a front view of the image-forming light source. FIG. 4 is a cross-sectional view schematically showing the image-forming light source and the lens unit in the first embodiment. FIG. 5 is a graph showing the relationship between lens shape and spherical aberration. FIG. 6 is a view similar to FIG. 4 showing the image-forming light source and the lens unit in a second embodiment. FIG. 7 is a front view of a shade.

[0015] Below, embodiments for carrying out the road surface drawing device according to the present invention are illustrated with reference to the accompanying drawings. The embodiments illustrated below are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be modified and improved from the following embodiments without departing from the spirit thereof within the scope of the claims. Furthermore, in the accompanying drawings, the dimensions of each component may be exaggerated to facilitate understanding.

[0016] <First embodiment> Figure 1 is a conceptual diagram showing a vehicle equipped with a road surface drawing device according to a first embodiment of the present invention, together with a drawn image drawn by the road surface drawing device. As shown in Figure 1, a vehicle 100 equipped with a road surface drawing device 1 is, for example, a four-wheeled automobile. In this specification, "right" means the right side relative to the traveling direction of the vehicle 100, and "left" means the left side relative to the traveling direction of the vehicle 100. Furthermore, "front" means the traveling direction of the vehicle 100.

[0017] 1 , a road surface drawing device 1 is mounted on each of the left and right front portions of a vehicle 100. The road surface drawing device 1 mounted on the right front portion projects a predetermined drawing image 50 diagonally forward and to the right of the vehicle 100. Similarly, the road surface drawing device 1 mounted on the left front portion projects a predetermined drawing image 50 diagonally forward and to the left of the vehicle 100.

[0018] Each road surface drawing device 1 mainly comprises a lighting unit 10, a control device CO, and a memory ME.

[0019] The configuration of the lighting unit 10 of one road surface drawing device 1 is the same as the configuration of the lighting unit 10 of the other road surface drawing device 1, except that the orientation with respect to the vehicle 100 is symmetrical. For this reason, the following will describe the lighting unit 10 of one road surface drawing device 1, and a description of the lighting unit 10 of the other road surface drawing device 1 will be omitted.

[0020] The lighting unit 10 of this embodiment mainly comprises a housing 20, an image-forming light source 30, and a lens unit 40.

[0021] The housing 20 has a lamp housing 21 and a light-transmitting outer cover 22. The lamp housing 21 has an opening at the front, and the outer cover 22 is fixed to the lamp housing 21 so as to close the opening. An image-forming light source 30 and a lens unit 40 are housed in the space formed by the lamp housing 21 and the outer cover 22.

[0022] FIG. 2 is a perspective view schematically illustrating the image-forming light source 30 and the lens unit 40 in this embodiment. FIG. 3 is a front view of the image-forming light source 30. As shown in FIGS. 2 and 3 , the image-forming light source 30 of this embodiment includes a light-emitting unit 31 that emits light and a substrate 33 on which the light-emitting unit 31 is mounted. The substrate 33 is disposed so that one main surface faces diagonally downward relative to the horizontal direction. The light-emitting unit 31 includes a plurality of light-emitting portions 32 that emit light, and the plurality of light-emitting portions 32 are disposed in a matrix on one main surface of the substrate 33. Each of the light-emitting portions 32 can individually change the amount of light emitted. In this embodiment, the light-emitting portions 32 are LEDs (Light Emitting Diodes), and the image-forming light source 30 is a so-called LED array.

[0023] The light emission area 35 capable of emitting light in such an image forming light source 30 is an area including the emission surfaces from which the light of the plurality of light emitting sections 32 is emitted, and in this embodiment, is rectangular in shape with a vertical width in front view that is greater than a horizontal width in front view.

[0024] FIG. 4 is a cross-sectional view schematically illustrating the image-forming light source 30 and the lens unit 40 in this embodiment. As shown in FIGS. 2 and 4 , the lens unit 40 in this embodiment is composed of a single convex meniscus lens 41. The convex meniscus lens 41 has an incident surface 42 located on the image-forming light source 30 side and on which light emitted from the image-forming light source 30 is incident, and an exit surface 43 located on the opposite side from the image-forming light source 30 side and from which light incident on the incident surface 42 exits. The incident surface 42 is convexly curved, and the exit surface 43 is concavely curved. The convex meniscus lens 41 is positioned so that the exit surface 43 faces diagonally downward relative to the horizontal. In this embodiment, the focal plane of the convex meniscus lens 41 on the image-forming light source 30 side is located on the exit region 35 of the image-forming light source 30.

[0025] The control device CO may be, for example, a microcontroller, an integrated circuit such as an IC (Integrated Circuit), an LSI (Large-scale Integrated Circuit), or an ASIC (Application Specific Integrated Circuit), or an NC (Numerical Control) device. When an NC device is used, the control device CO may or may not use a machine learning device. The control device CO is electrically connected to the memory ME and the image forming light source 30.

[0026] The memory ME is configured to store information and to be able to read the stored information. The memory ME is, for example, a non-transitory recording medium, and is preferably a semiconductor recording medium such as a random access memory (RAM) or a read-only memory (ROM), but may also include any type of recording medium, such as an optical recording medium or a magnetic recording medium. Note that "non-transitory" recording medium includes all computer-readable recording media except for transient, propagating signals, and does not exclude volatile recording media. The memory ME stores programs for controlling the image-forming light source 30 and information necessary for such control, and the control device CO reads the programs and information stored in the memory ME.

[0027] The control device CO of this embodiment reads out a program for controlling the image forming light source 30 from the memory ME and controls the image forming light source 30 .

[0028] Next, the operation of the road surface drawing device 1 will be described.

[0029] The control device CO controls the image-forming light source 30 to cause the image-forming light source 30 to emit light L1 that forms the drawn image 50. The light L1 emitted from the image-forming light source 30 enters the convex meniscus lens 41 from the incident surface 42 and exits from the exit surface 43. The light is irradiated onto the road surface, and the drawn image 50 is projected onto the road surface. As described above, the focal plane of the convex meniscus lens 41 on the image-forming light source 30 side is located on the exit area 35 of the image-forming light source 30. Therefore, the drawn image 50 projected onto the road surface is an image of the light L1 emitted by the image-forming light source 30 that has been inverted vertically and horizontally.

[0030] The drawn image 50 of this embodiment is composed of three inverted V-shaped images, and these three images are aligned in a direction away from the vehicle. However, the drawn image 50 is not limited to this.

[0031] As described above, the road surface drawing device 1 of this embodiment includes an image forming light source 30 that emits light L1 that forms a predetermined drawn image 50, and a lens unit 40 that projects the drawn image 50 onto the road surface. The lens unit 40 is made up of a single convex meniscus lens 41 that has a convexly curved incident surface 42 on which the light L1 is incident, and a concavely curved exit surface 43 from which the light L1 that has entered the incident surface 42 exits.

[0032] Generally, spherical aberration varies depending on the lens shape. Figure 5 shows the relationship between lens shape and spherical aberration. Here, a convex meniscus lens, a plano-convex lens, and a biconvex lens, all of which share a refractive index n = 1.5 and a focal length f = 1, are compared. In Figure 5, the arrows indicate the direction of light incidence on each lens. The horizontal axis represents the curvature of the surface on the light incidence side. The vertical axis represents the magnitude of spherical aberration. Comparing a convex meniscus lens in which the incident surface onto which light is incident and the exit surface from which light is emitted are arranged so as to have a convex shape, with a plano-convex lens in which the incident surface onto which light is incident and the exit surface from which light is emitted, the former tends to have smaller spherical aberration. In the road surface painting device 1 of this embodiment, the lens unit 40 consists of a single convex meniscus lens 41 having a convexly curved incident surface 42 onto which light L1 is incident and a concavely curved exit surface 43 from which light L1 incident on the incident surface 42 exits. Therefore, with the road surface drawing device 1 of this embodiment, the drawn image 50 drawn on the road surface can be made clearer than when the lens unit 40 is a plano-convex lens and light is incident on the flat side of the plano-convex lens. Also, because the lens unit 40 in this embodiment is made up of a single convex meniscus lens 41, an increase in the number of parts can be suppressed compared to when the lens unit 40 is made up of multiple lenses.

[0033] Furthermore, by making the incident surface 42 convex, the divergence angle of the incident light can be reduced, and the widening of the exit surface 43 can be prevented. This can be advantageous for reducing the size of the road surface drawing device 1. Furthermore, by making the exit surface 43 concave, astigmatism, field curvature, and distortion can be corrected, and a clear image can be drawn.

[0034] In the road surface drawing device 1 of this embodiment, the focal plane of the convex meniscus lens 41 on the image-forming light source 30 side is located on the emission area 35 that emits the light L1 from the image-forming light source 30. Therefore, the road surface drawing device 1 of this embodiment can draw a clear image.

[0035] The image forming light source 30 includes a light emitting unit 31 in which a plurality of light emitting sections 32, each capable of individually changing the amount of light emitted, are arranged in a matrix and emit light L1 that forms the drawn image 50. Therefore, the road surface drawing device 1 of this embodiment can project a plurality of still images and moving images onto the road surface.

[0036] Second Embodiment Next, a second embodiment will be described in detail. Note that components that are the same as or equivalent to those in the first embodiment will be assigned the same reference numerals unless otherwise specified, and duplicate descriptions will be omitted.

[0037] Fig. 6 is a diagram showing the image forming light source 30 and the lens unit 40 in this embodiment, similar to Fig. 4. As shown in Fig. 6, the road surface drawing device 1 of this embodiment differs from the road surface drawing device 1 of the first embodiment mainly in that the configuration of the image forming light source 30 is different from the configuration of the image forming light source 30 of the first embodiment.

[0038] The image forming light source 30 of this embodiment mainly comprises a light emitting unit 36 ​​and a shade 37. The light emitting unit 36 ​​of this embodiment emits light L2 toward the incident surface 42 of the convex meniscus lens 41 of the lens unit 40. The light emitting unit 36 ​​may be, for example, an LED.

[0039] FIG. 7 is a front view of the shade 37. As shown in FIGS. 6 and 7 , the shade 37 of this embodiment is a non-light-transmitting plate-like member, and the outer shape of the shade 37 is a rectangle that is elongated in the vertical direction. The shade 37 is provided with an opening 38 that is a hole that penetrates in the thickness direction. In this embodiment, the opening 38 consists of three V-shaped holes that are aligned in the vertical direction. The shade 37 is disposed between the light exit portion 36 and the convex meniscus lens 41 so that one main surface faces the light exit portion 36, and the other main surface faces diagonally downward relative to the horizontal direction.

[0040] In this embodiment, the focal plane of the convex meniscus lens 41 on the image-forming light source 30 side is located on the other main surface of the shade 37 .

[0041] Light L2 emitted from light exit portion 36 is irradiated onto one main surface of shade 37, and the entire opening 38 is included in this irradiation area. Therefore, shade 37 emits light L2 from the entire opening 38, and light L2 irradiated onto parts of shade 37 other than opening 38 is blocked by shade 37. In other words, the emission area 35 in this embodiment is opening 38. In this embodiment as well, the focal plane of convex meniscus lens 41 on the image-forming light source 30 side is located on emission area 35 of image-forming light source 30.

[0042] In this embodiment, the image of light L2 passing through the opening 38 of the shade 37 is an image of three V-shaped images lined up vertically. This light L2 is incident on the incident surface 42 of the convex meniscus lens 41 and exits from the exit surface 43. An image obtained by inverting the image of light L2 passing through the opening 38 vertically and horizontally is projected onto the road surface. In this way, as in the first embodiment, a drawn image 50 consisting of three inverted V-shaped images lined up is projected onto the road surface. In other words, the shade 37 blocks a portion of the light L2 emitted from the light exit portion 36 so that the light L2 emitted from the light exit portion 36 becomes light that forms the drawn image 50.

[0043] Similarly to the first embodiment, the road surface drawing device 1 of this embodiment can also clearly draw the drawn image 50 on the road surface while suppressing an increase in the number of parts.

[0044] Although the present invention has been described above using the above-mentioned embodiments as examples, the present invention is not limited to these.

[0045] For example, in the above embodiment, an example was shown in which the road surface drawing device 1 is mounted on the left front and right front of the vehicle 100, but this is not limiting. For example, the road surface drawing device 1 may be mounted on the rear, left side, or right side of the vehicle 100.

[0046] In the first embodiment, the image-forming light source 30 is a so-called LED array. However, the image-forming light source 30 may be configured to emit light that forms a predetermined image, and may be configured, for example, to combine a light source such as an LED with a liquid crystal on silicon (LCOS), a digital mirror device (DMD), or the like.

[0047] In the second embodiment, the shade 37 is made of a plate-like member having the opening 38. However, the shade 37 may be configured to block a portion of the light L2 emitted from the light emitting portion 36 so that the light L2 emitted from the light emitting portion 36 forms the drawn image 50.

[0048] Furthermore, in the above first and second embodiments, an example was given in which the focal plane of the convex meniscus lens 41 on the image-forming light source 30 side is located on the emission region 35 that emits light that forms a predetermined image in the image-forming light source 30. However, the focal plane does not have to be located on the emission region 35.

[0049] According to the present invention, a road surface drawing device is provided that can clearly draw images on the road surface while suppressing an increase in the number of parts, and can be used in fields such as automobiles and aircraft, which are vehicles that can travel on road surfaces.

Claims

1. A road surface drawing device comprising: an image forming light source that emits light that forms a predetermined drawn image; and a lens unit that projects the drawn image onto the road surface, wherein the lens unit is composed of a single convex meniscus lens that has a convexly curved entrance surface onto which the light enters and a concavely curved exit surface from which the light exits.

2. The road surface drawing device according to claim 1, wherein the focal plane of the convex meniscus lens on the image-forming light source side is located on an emission area of ​​the image-forming light source from which the light is emitted.

3. The road surface drawing device according to claim 1 or 2, characterized in that the image forming light source includes a light emitting unit that is arranged with a plurality of light emitting sections that can individually change the amount of light emitted, and that emits light that forms the drawn image.

4. The road surface drawing device according to claim 1 or 2, characterized in that the image forming light source includes a light emitting unit that emits light, and a shade that blocks a portion of the light emitted from the light emitting unit so that the light emitted from the light emitting unit becomes light that forms the drawn image.

Images