Vehicle lighting device

Abstract

To provide a vehicular lighting apparatus capable of ameliorating a problem in which a pedestrian is overlooked by a driver, even under adverse conditions such as night and rainy weather.SOLUTION: A vehicular lighting apparatus 1 comprises: a low-beam irradiation part (a low-beam unit 7) which illuminates a lower irradiation region (a low-beam irradiation region 11) on a lower side ahead of a vehicle 2; a pattern irradiation part (a projector unit 8) which irradiates, with irradiation light, a lateral irradiation region (a right-side pattern irradiation region 12) on a lateral side of a traveling road of the vehicle 2 in an irradiation pattern such that bright regions 13 and dark regions 14 are alternately repeated; an environmental information acquisition device 20 which acquires information about a moisture environment around the vehicle 2; and a control part (a lamp control ECU 9) which changes an irradiation mode of the low-beam irradiation part 7 or / and the pattern irradiation part 8 on the basis of the information acquired by the environmental information acquisition device 20. In one mode, in rainy weather at night, the control part 9 causes the low-beam irradiation part 7 to reduce brightness of irradiation light, and causes the pattern irradiation part 8 to increase brightness of irradiation light.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] A lighting device for a vehicle has been proposed that allows a driver to clearly see pedestrians while suppressing dazzle to the pedestrians (see, for example, Patent Document 1). The lighting device for a vehicle in Patent Document 1 reduces the amount of illumination on the upper body of a pedestrian according to the distance to the pedestrian acquired by a pedestrian detection sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-184614 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the technology of Patent Document 1 reduces dazzling to pedestrians, there is a risk that visibility of pedestrians from the driver's side may be insufficient under adverse conditions such as at night and in the rain.

[0005] The present invention has been made in view of the above-mentioned circumstances, and aims to provide a vehicle lighting device that can reduce the likelihood of a driver overlooking pedestrians even under adverse conditions such as nighttime and rainy weather, and ultimately to further improve traffic safety and contribute to the development of a sustainable transportation system. [Means for solving the problem]

[0006] (1) A vehicle lighting device including: a low beam illumination unit (e.g., low beam unit 7 described later) that illuminates a lower illumination area (e.g., low beam illumination area 11 described later) on the lower front side of a vehicle (e.g., vehicle 2 described later); a pattern illumination unit (e.g., projector unit 8 described later) that irradiates a side illumination area (e.g., right pattern illumination area 12 described later) on the side of a roadway of the vehicle in an illumination pattern in which bright areas (e.g., bright areas 13 described later) and dark areas (e.g., dark areas 14 described later) are alternately repeated; an environmental information acquisition device (e.g., environmental information acquisition device 20 described later) that acquires information related to the moisture environment around the vehicle; and a control unit (e.g., lamp control ECU 9 described later) that changes the illumination mode of the low beam illumination unit and / or the pattern illumination unit based on the information acquired by the environmental information acquisition device.

[0007] (2) The control unit dims the light emitted by the low beam irradiation unit and / or increases the light emitted by the pattern irradiation unit based on environmental information acquired by the environmental information acquisition device, the environmental information indicating that it is night and rainy. [Effects of the Invention]

[0008] In the vehicle lighting device of (1), when the environmental information acquisition device acquires information related to the moisture environment around the vehicle and transmits it to the control unit, the low beam illumination emitted from the low beam illumination unit to the lower illumination area and the pattern illumination emitted from the pattern illumination unit to pedestrians can be changed according to the moisture environment around the vehicle, thereby maintaining pedestrian visibility from the driver's side. This will further improve traffic safety and contribute to the development of a sustainable transportation system.

[0009] In the vehicle lighting device of (2), when it is night and raining, the control unit reduces the light emitted by the low beam irradiation unit, thereby reducing the degree to which pedestrians are illuminated by the low beam irradiation light reflected on the water surface on the road surface. As a result, the contrast of the irradiation pattern emitted from the pattern irradiation unit to pedestrians is less likely to be impaired, and pedestrian visibility from the driver's side is maintained. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating a state in which illumination light is emitted by a vehicle lighting device according to an embodiment of the present invention; [Figure 2] 1 is a configuration diagram of a vehicle lighting device according to an embodiment of the present invention; [Figure 3] 3 is a diagram showing the illumination areas of the lamps in the vehicle lighting device of FIG. 2. FIG. [Figure 4] 3 is a diagram showing an illumination area of a lamp when the vehicle lighting device of FIG. 2 is operating in a low beam mode. FIG. [Figure 5] 3 is a diagram showing an example of an irradiation pattern by a pattern irradiation unit in the vehicle lighting device of FIG. 2. FIG. [Figure 6] 3 is a diagram showing an example of an operation mode of a low beam irradiation unit and a pattern irradiation unit when an environmental information acquisition device of the vehicle lighting device of FIG. 2 detects that it is raining. FIG. [Figure 7] 10 is a diagram showing another example of the operation mode of the low beam irradiation unit and the pattern irradiation unit when the environmental information acquisition device of the vehicle lighting device of FIG. 2 detects that it is raining. [Figure 8] 10 is a diagram showing another example of the operation mode of the low beam irradiation unit and the pattern irradiation unit when the environmental information acquisition device of the vehicle lighting device of FIG. 2 detects that it is raining. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present invention will be described below with reference to the drawings. In the following description, an illumination area refers to an area illuminated by light from a lighting fixture, and an illumination pattern refers to the illuminance in the illumination area, a pattern formed by light and dark areas, the outline shape of the illumination area, or other illumination forms.

[0012] 1 is a schematic diagram showing the state of illumination light emitted by a vehicle lighting device 1 according to an embodiment of the present invention. The light distribution of the light emitted from the vehicle lighting device 1 is evaluated based on an illumination pattern formed on a test screen 3, which is a predetermined imaginary vertical plane set directly in front of the vehicle lighting device 1, for example, 25 m ahead, provided on a vehicle 2.

[0013] Fig. 2 is a configuration diagram of the vehicle lighting device 1, and Fig. 3 is a diagram showing the illumination areas of each lamp in the vehicle lighting device 1. A high beam unit 6, a low beam unit 7, and a projector unit 8 are arranged in each of the lamps, left headlight unit 4 and right headlight unit 5, in that order from the inside to the outside in the width direction of the vehicle 2. In each of the left headlight unit 4 and right headlight unit 5, the high beam unit 6, low beam unit 7, and projector unit 8 are operated under the control of a lamp control ECU 9.

[0014] The high beam unit 6 includes a light-emitting element serving as a light source, a reflector, a light-shielding plate that defines an illumination area, and a lens. Power is supplied from a power source (not shown) in response to a control signal from the lamp control ECU 9, causing the light-emitting element to emit light. The light from the light-emitting element is reflected by the reflector. The light reflected from the reflector is then emitted from the lens toward a high beam illumination area 10 defined by the light-shielding plate.

[0015] The low beam unit 7 includes a light-emitting element serving as a light source, a reflector, a light-shielding plate that defines an illumination area, and a lens. The light-emitting element emits light when power is supplied from a power source (not shown) in response to a control signal from the lamp control ECU 9. The light from the light-emitting element is reflected by the reflector. The light reflected from the reflector is directed from the lens toward the low beam illumination area 11 defined by the light-shielding plate.

[0016] The projector unit 8 includes a light-emitting element serving as a light source, a spatial light modulator, and a lens. The spatial light modulator may be, for example, a device that reflects light while independently modulating a number of reflective elements, such as a DMD (Digital Micromirror Device). In this case, the projector unit 8 employs a DLP (Digital Light Processing: registered trademark) configuration using a DMD, and can project light from the lens to the area ahead of the vehicle 2 and other surrounding areas in a variety of predetermined illumination patterns.

[0017] The illumination pattern can take the form of not only various types of still image patterns but also moving image patterns. In response to a control signal from the lamp control ECU 9, driving power is supplied from a power source (not shown) to the light-emitting element, causing it to emit light. The light from this light-emitting element is spatially modulated by a spatial light modulator driven in response to a control signal from the lamp control ECU 9, and light is irradiated from the lens of the projector unit 8 to the front of the vehicle 2 and other surrounding areas in various predetermined illumination patterns. In other words, the projector unit 8 constitutes a pattern illumination unit that can change the form of the illumination pattern.

[0018] 3, the areas illuminated by the high beam unit 6, the low beam unit 7, and the projector unit 8 when light is illuminated onto the test screen 3 from the vehicle lighting device 1 in Fig. 1 will be described. Here, the area illuminated by the projector unit 8 refers to the area illuminated by the projector unit 8 of the right headlight unit 5.

[0019] The area illuminated by the projector unit 8 of the left headlight unit 4 is symmetrical to the area illuminated by the projector unit 8 of the right headlight unit 5 with respect to line VV as the axis of symmetry, but is not shown in the figure.

[0020] The configuration and operation of the projector unit 8 of the left headlight unit 4 is similar to that of the projector unit 8 of the right headlight unit 5. Therefore, hereinafter, the configuration and operation of the projector unit 8 of the left headlight unit 4 will be explained by citing the explanation for the projector unit 8 of the right headlight unit 5.

[0021] The low beam illumination area 11 illuminated by the low beam unit 7 has an oncoming lane cutoff line extending parallel to the HH line (horizontal line) to the right of the VV line (vertical line) in the center of the left-right direction on the test screen 3. It also has a host lane cutoff line extending along the HH line at a position higher than the oncoming lane cutoff line to the left of the VV line. The oncoming lane cutoff line and the host lane cutoff line are connected by an oblique cutoff line that is inclined with respect to the HH line. The low beam illumination area 11 is an illumination area on the lower front side of the vehicle 2.

[0022] High beam illumination area 10 illuminated by high beam unit 6 is rectangular with long sides parallel to the HH line and short sides parallel to the VV line, and the intersection of its diagonal lines is located at a position that approximately coincides with the intersection of the HH line and the VV line. High beam illumination area 10 overlaps with low beam illumination area 11 in a lower partial area that includes the portions of the oncoming lane cut-off line and the own lane cut-off line closer to the VV line. High beam illumination area 10 is an upper illumination area that is above low beam illumination area 11, which is a lower illumination area, and is toward the center of vehicle 2 in the vehicle width direction.

[0023] The right-side pattern illumination area 12, which is the area illuminated by the projector unit 8 of the right-side headlight unit 5, can have its illumination pattern, such as the outline shape of the area and the form of the illumination pattern within the area, changed in various ways by a mode switching signal from the lamp control ECU 9. However, regardless of the form the right-side pattern illumination area 12 takes, it is a side illumination area on the side of the road on which the vehicle is traveling, occupying an area further outward in the vehicle width direction than the upper illumination area (high beam illumination area 10) and above the lower illumination area (low beam illumination area 11).

[0024] Due to the capabilities of the projector unit 8, the right-side pattern illumination area 12 can take a wide form that includes an overlapping area 12a that overlaps with the high beam illumination area 10. In this form, the right-side pattern illumination area 12 forms a horizontal trapezoid whose height direction is parallel to the HH line and whose upper and lower bases are parallel to the VV line. The lower base of this trapezoid, which is relatively farther from the VV line, is longer than the upper base, which is relatively closer to the VV line. In other words, the right-side pattern illumination area 12 has a shape whose dimension along the VV line widens outward in the vehicle width direction of the vehicle 2.

[0025] As described above, the high beam unit 6, low beam unit 7, and projector unit 8 of each of the left headlight unit 4 and the right headlight unit 5 operate under the control of the lamp control ECU 9. The lamp control ECU 9 switches the operation mode of the vehicle lighting device 1 based on outputs from a higher-level ECU (not shown), a light switch, a light switch lever, and the like mounted on the vehicle 2, as well as information acquired by the environmental information acquisition device 20 (described below). That is, the lamp control ECU 9 supplies control signals to the high beam unit 6, low beam unit 7, and projector unit 8 to switch the operation mode of each of these units.

[0026] FIG. 4 is a diagram showing the illumination area of the light emitted by the vehicle lighting device 1 when the operating mode is set to low beam mode by the lamp control ECU 9. At night, when the light switch is in the "auto" position and the light switch lever is in a position other than low beam, the vehicle lighting device 1 is often in high beam mode. In this state, when the camera detects an oncoming vehicle, a vehicle ahead, or a certain number of street lights, the lamp control ECU 9 switches the operating mode of the vehicle lighting device 1 to low beam mode. In low beam mode, under the control of the lamp control ECU 9, the high beam unit 6 is turned off, the low beam unit 7 illuminates the low beam illumination area 11, and the projector unit 8 illuminates the right pattern illumination area 12.

[0027] In low beam mode, the right pattern illumination area 12 occupies a wide, horizontally trapezoidal area including the overlap area 12a described above. This wide area is illuminated with pattern illumination light from the projector unit 8 in a light-dark mixed illumination pattern 15, in which bright areas 13 and dark areas 14 are alternately repeated, as shown in Fig. 5. The light-dark mixed illumination pattern 15 in Fig. 5 is, in particular, a diagonal diamond lattice pattern made up of bright areas 13 in a diagonal diamond lattice mesh pattern and dark areas 14 surrounded by these bright areas 13.

[0028] The light emitted by the projector unit 8 of the right headlight unit 5 in the mixed light and dark illumination pattern 15 allows the driver to easily recognize the presence of pedestrians on the roadside, taking advantage of the characteristics of human vision. This can reduce the likelihood of the driver overlooking pedestrians even under adverse conditions such as at night or in the rain.

[0029] Here, the fact that it is raining around the current location of the vehicle 2 is recognized based on information acquired by the environmental information acquisition device 20. The camera 16, rain sensor 17, wiper switch 18, and car navigation system 19 in Fig. 2 constitute the environmental information acquisition device 20, which acquires information related to the moisture environment around the vehicle 2, either individually or in cooperation with one another.

[0030] The camera 16 acquires information related to rainy weather based on the conditions of its imaging field of view. The rain sensor 17 detects raindrops on the outer surface of the windshield. The wiper switch 18 is turned "on" when raindrops are present on the windshield, and this "on" state can be considered to correspond to a detection value indicating a high probability of rain. The car navigation system 19 determines that it is raining around the vehicle 2 based on the current location of the vehicle 2, the time, the weather forecast, etc. If the rain sensor 17 alone constitutes the environmental information acquisition device 20, it can detect rainy weather with a relatively simple configuration.

[0031] Meanwhile, in the vehicle 2, the day / night distinction is identified by the lamp control ECU 9 based on the detected values of the illuminance around the vehicle 2 obtained by the camera 16, the rain sensor 17, etc., and the current time information in the car navigation system 19, etc.

[0032] 6 is a diagram showing an example of the operation of the low beam unit 7 and the projector unit 8 as a patterned illumination unit when the environmental information acquisition device 20 of the vehicle lighting device of FIG. 2 detects that it is raining. In FIG. 6, during the time period from time t0 to time t1, the output of the rain sensor 17 is a value corresponding to "fine weather." At this time, the low beam unit 7 is emitting low beams with a normal light intensity in "normal" mode. Also, at this time, the projector unit 8 is emitting patterned illumination light with a normal light intensity in "normal" mode.

[0033] Because it is a "clear day," the road surface on which the vehicle 2 is traveling is rarely wet or has puddles. Therefore, even if the low beam illumination is maintained at a normal light intensity, the low beam is not reflected from the water surface and illuminates the pedestrian, thereby preventing the contrast of the illumination pattern by the projector unit 8 from being reduced. Therefore, the light emitted by the projector unit 8 in the mixed light and dark illumination pattern 15 allows the driver to easily recognize the presence of a pedestrian on the roadside, due to the characteristics of human vision.

[0034] On the other hand, in Figure 6, after time t1, the output of the rain sensor 17 is a value corresponding to "rainy weather." At this time, the low beam unit 7 is in a "dim" mode, which emits less light than in the "normal" mode and includes an off state. In this example, the projector unit 8 remains in the "normal" mode and emits a pattern of light with a normal light intensity. In "rainy weather," the road surface on which the vehicle 2 is traveling becomes wet and puddles occur.

[0035] However, because the low beam light emitted by the low beam unit 7 is dimmed, the degree to which pedestrians are illuminated by the low beam light reflected off the water surface on the road can be reduced. This reduces the reduction in contrast caused by the pattern illumination emitted from the projector unit 8 onto pedestrians. Therefore, even under adverse conditions such as nighttime and rainy weather, the light emitted by the light and dark mixed illumination pattern 15 from the projector unit 8 works effectively, and the presence of pedestrians on the roadside can be easily recognized by the driver due to the characteristics of human vision.

[0036] In FIG. 6, the operation mode of the low beam unit 7 is switched between "normal" and "dim" in accordance with the output of the rain sensor 17 under the control of the lamp control ECU 9.

[0037] Fig. 7 is a diagram showing another example of the operation of the low beam unit 7 and the projector unit 8 as a pattern irradiation unit when the environmental information acquisition device 20 of the vehicle lighting device of Fig. 2 detects that it is raining. In Fig. 7, the operations of the rain sensor 17, the low beam unit 7, and the projector unit 8 in the time period from time t0 to time t1 are the same as those in Fig. 6.

[0038] 7 differs from the case of FIG. 6 in that after time t1, even if the output of rain sensor 17 indicates a value corresponding to "rainy weather," low beam unit 7 remains in "normal" mode, while projector unit 8 switches from "normal" mode to "increased brightness" mode. In the "increased brightness" mode, projector unit 8 emits patterned illumination light at a light intensity higher than the normal light intensity.

[0039] Therefore, even if the low beam light with normal light intensity is reflected off the water surface and illuminates a pedestrian, it is unlikely to impair the contrast of the illumination pattern by the projector unit 8. Therefore, the light emitted by the projector unit 8 in the amplified light and dark mixed illumination pattern 15 allows the driver to easily recognize the presence of a pedestrian on the roadside due to the characteristics of human vision.

[0040] In FIG. 7, the operation mode of the projector unit 8 is switched between "normal" and "bright" in accordance with the output of the rain sensor 17 under the control of the lamp control ECU 9.

[0041] Fig. 8 is a diagram showing yet another example of the operation of the low beam unit 7 and the projector unit 8 as a pattern irradiation unit when the environmental information acquisition device 20 of the vehicle lighting device of Fig. 2 detects that it is raining. In Fig. 8, the operations of the rain sensor 17, the low beam unit 7, and the projector unit 8 in the time period from time t0 to time t1 are the same as those in Fig. 6.

[0042] The difference between the example in FIG. 8 and the example in FIG. 6 is that after time t1, when the output of rain sensor 17 indicates a value corresponding to "rainy weather," low beam unit 7 switches from "normal" mode to "dimming" mode, and simultaneously projector unit 8 switches from "normal" mode to "increasing" mode. In the example in FIG. 8, even if the low beam light reflects off the water surface and illuminates a pedestrian, the low beam light is dimmed below the normal level, and projector unit 8 illuminates the pattern light at a higher level than the normal level. This reduces the reflection of the low beam light on the water surface, and further increases the light emitted from projector unit 8 of light-dark mixed illumination pattern 15 toward the pedestrian, ensuring contrast through pattern illumination. As a result, due to the characteristics of human vision, the presence of a pedestrian on the roadside is clearly recognized by the driver.

[0043] In FIG. 8, the switching of the operation modes in the low beam unit 7 and the projector unit 8 in accordance with the output of the rain sensor 17 is performed under the control of the lamp control ECU 9.

[0044] The vehicle lighting device 1 of this embodiment provides the following effects.

[0045] In the vehicle lighting device 1 of (1), when the environmental information acquisition device 20 acquires information corresponding to a situation in which the road surface is highly likely to be wet and transmits it to the lamp control ECU 9, the lamp control ECU 9 controls the low beam unit 7 to dim the light emitted. This reduces the degree to which pedestrians are illuminated by the low beam light reflected on the road surface. This also reduces the reduction in contrast caused by the patterned illumination projected from the projector unit 8 onto pedestrians. As a result, pedestrian visibility from the driver's side is maintained.

[0046] In the vehicle lighting device 1 of (2), when it is night and raining, the lamp control ECU 9 controls the low beam unit 7 to dim the light emitted, thereby reducing the degree to which pedestrians are illuminated by the low beam light reflected off the water surface on the road. This makes it difficult for the contrast of the illumination pattern emitted from the projector unit 8 to be impaired, and maintains pedestrian visibility from the driver's side.

[0047] Although the embodiments of the present invention have been described above, the present invention is not limited thereto. Detailed configurations may be modified as appropriate within the spirit and scope of the present invention. In the above-described embodiment, under the control of the lamp control ECU 9, the low beam unit 7 is controlled to dim the light emitted by the low beam unit 7 and / or the projector unit 8 is controlled to increase the light emitted by the projector unit 8 in accordance with information related to the moisture environment around the vehicle acquired by the environmental information acquisition device 20. Alternatively, for example, the low beam unit 7 and / or the projector unit 8 may be controlled in a similar manner by a host ECU that also obtains information related to the moisture environment around the vehicle through external communications. Furthermore, the illumination pattern of the projector unit 8 is not limited to the above-described light-dark mixed illumination pattern 15, and a checkered illumination pattern or a striped illumination pattern may also be used. [Explanation of symbols]

[0048] 1...Vehicle lighting device 2...Vehicle 3...Test screen 4...Left headlight unit 5...Right headlight unit 6...High beam unit 7...Low beam unit 8...Projector unit (pattern projection unit) 9...Lighting control ECU 10...High beam illumination area (upper illumination area) 11...Low beam illumination area (lower illumination area) 12...Right pattern illumination area (side illumination area) 12a…overlapping area 13...Bright area 14...Dark area 15...Light and dark mixed illumination pattern 16...Camera 17...Rain sensor 18...Wiper switch 19...Car navigation system 20...Environmental information acquisition device

Claims

[Claim 1] a low beam illumination unit that illuminates a lower illumination area at a lower front side of the vehicle, the lower illumination area including a center of the vehicle in a vehicle width direction; a pattern irradiation unit that irradiates a side illumination area on the side of a road along which the vehicle is traveling, the side illumination area not including an area directly in front of the center of the vehicle in a vehicle width direction, with an irradiation pattern in which light areas and dark areas are alternately repeated; an environmental information acquisition device that acquires information related to the moisture environment around the vehicle; a control unit that changes the illumination mode of the low beam illumination unit and the pattern illumination unit based on the information acquired by the environmental information acquisition device, When the control unit acquires environmental information indicating that it is night and rainy from the environmental information acquisition device while the low beam irradiation unit and the pattern irradiation unit are emitting irradiation light, the control unit reduces the illumination light of the low beam irradiation unit and increases the illumination light of the pattern irradiation unit compared to when the environmental information is not acquired. Vehicle lighting device.

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