U.S. patent application number 16/531632 was filed with the patent office on 2020-02-06 for vehicle lamp.
This patent application is currently assigned to KOITO MANUFACTURING CO., LTD.. The applicant listed for this patent is KOITO MANUFACTURING CO., LTD.. Invention is credited to Tatsuma Kitazawa.
Application Number | 20200039420 16/531632 |
Document ID | / |
Family ID | 69168564 |
Filed Date | 2020-02-06 |
United States Patent
Application |
20200039420 |
Kind Code |
A1 |
Kitazawa; Tatsuma |
February 6, 2020 |
VEHICLE LAMP
Abstract
A vehicle lamp includes: a light distribution controller
configured to generate a light distribution pattern including a
shaded portion in which a margin region is added around a snow
particle; and a variable light distribution lamp capable of
generating a beam having an intensity distribution corresponding to
the light distribution pattern. And at least one of a size and a
shape of the margin region is variable.
Inventors: |
Kitazawa; Tatsuma;
(Shizuoka-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KOITO MANUFACTURING CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
KOITO MANUFACTURING CO.,
LTD.
Tokyo
JP
|
Family ID: |
69168564 |
Appl. No.: |
16/531632 |
Filed: |
August 5, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F21W 2102/17 20180101;
B60Q 2300/41 20130101; B60Q 2300/056 20130101; B60Q 2300/312
20130101; B60Q 2300/054 20130101; B60Q 1/143 20130101; B60Q 2300/42
20130101; F21S 41/65 20180101; B60Q 2300/45 20130101 |
International
Class: |
B60Q 1/14 20060101
B60Q001/14; F21S 41/65 20060101 F21S041/65 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 6, 2018 |
JP |
2018-147921 |
Aug 9, 2018 |
JP |
2018-150097 |
Claims
1. A vehicle lamp comprising: a light distribution controller
configured to generate a light distribution pattern including a
shaded portion in which a margin region is added around a snow
particle; and a variable light distribution lamp capable of
generating a beam having an intensity distribution corresponding to
the light distribution pattern, wherein at least one of a size and
a shape of the margin region is variable.
2. The vehicle lamp according to claim 1, wherein at least one of
the size and the shape of the margin region corresponds to a
position of the snow particle.
3. The vehicle lamp according to claim 2, wherein the margin region
becomes smaller in a case where a position of the snow particle
becomes higher, and becomes larger in a case the position of the
snow particle becomes lower.
4. The vehicle lamp according to claim 2, wherein the margin region
becomes larger in a case where the snow particle becomes farther
from a vanishing point.
5. The vehicle lamp according to claim 1, wherein a vehicle speed
is reflected in the at least one of the size and the shape of the
margin region.
6. The vehicle lamp according to claim 2, wherein a vehicle speed
is reflected in the at least one of the size and the shape of the
margin region.
7. The vehicle lamp according to claim 3, wherein a vehicle speed
is reflected in the at least one of the size and the shape of the
margin region.
8. The vehicle lamp according to claim 4, wherein a vehicle speed
is reflected in the at least one of the size and the shape of the
margin region.
9. The vehicle lamp according to claim 1, wherein an output of a
raindrop sensor is reflected in the at least one of the size and
the shape of the margin region.
10. The vehicle lamp according to claim 2, wherein an output of a
raindrop sensor is reflected in the at least one of the size and
the shape of the margin region.
11. The vehicle lamp according to claim 3, wherein an output of a
raindrop sensor is reflected in the at least one of the size and
the shape of the margin region.
12. The vehicle lamp according to claim 4, wherein an output of a
raindrop sensor is reflected in the at least one of the size and
the shape of the margin region.
13. The vehicle lamp according to claim 5, wherein an output of a
raindrop sensor is reflected in the at least one of the size and
the shape of the margin region.
14. The vehicle lamp according to claim 6, wherein an output of a
raindrop sensor is reflected in the at least one of the size and
the shape of the margin region.
15. The vehicle lamp according to claim 7, wherein an output of a
raindrop sensor is reflected in the at least one of the size and
the shape of the margin region.
16. The vehicle lamp according to claim 8, wherein an output of a
raindrop sensor is reflected in the at least one of the size and
the shape of the margin region.
17. The vehicle lamp according to claim 1, wherein the light
distribution controller is configured to detect the snow particle
based on an image of reflected light obtained depending on a probe
light irradiated by an infrared illumination device, the image
being captured by an infrared camera.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
USC 119 from Japanese Patent Applications No. 2018-147921 filed on
Aug. 6, 2018 and No. 2018-150097 filed on Aug. 9, 2018, the
contents of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a vehicle lamp.
BACKGROUND
[0003] Vehicle lamps are important for traveling safely during
nighttime or in a tunnel. When a driver prioritize visibility
thereof and illuminate a wide range in front of a vehicle, there is
a problem that glare is given to a driver of a preceding vehicle or
an oncoming vehicle existing in front of the vehicle (hereinafter,
referred to as a front vehicle) or a pedestrian.
[0004] In recent years, an adaptive driving beam (ADB) technique,
which dynamically and adaptively controls a light distribution
pattern based on a state around a vehicle, is proposed. The ADB
technology detects existence of the front vehicle or the
pedestrian, and reduces the glare given to the driver of the front
vehicle or to the pedestrian by, for example, dimming or
extinguishing lighting in a region corresponding to the front
vehicle or the pedestrian.
[0005] When a head lamp is lighted during snowfall (or rainfall),
there is a problem that beams are reflected by snow particles and
give glare to a driver, making it difficult for the driver to view
forward. In order to solve this problem, the present inventors
studied control of detecting snow particles and shading surrounding
regions thereof.
[0006] In a system capable of performing ultra-high-speed control,
it is possible to make shaded regions as close as possible to sizes
of the snow particles. However, such a system is very expensive and
impractical. Therefore, in a practical system, a range of shaded
portions is necessarily expanded to include surrounding regions of
the snow particles. If the shaded portions are large, since beams
are not irradiated onto objects that overlap the snow particles
behind the snow particles, there is a problem that visibility is
reduced.
[0007] The present invention is made in view of this circumstance,
and an exemplary object of such an aspect is to improve visibility
of a front of a vehicle during snowfall.
SUMMARY
[0008] An aspect of the present invention relates to a vehicle
lamp. The vehicle lamp includes: a light distribution controller
configured to generate a light distribution pattern including
shaded portions in which margin regions are added around snow
particles; and a variable light distribution lamp capable of
generating a beam having an intensity distribution corresponding to
the light distribution pattern. At least one of sizes and shapes of
the margin regions are variable.
[0009] Any combinations of constituting elements described above,
and implementations of the invention in form of methods, devices,
systems, and the like are also effective as aspects of the present
invention.
[0010] According to the present invention, the visibility of the
front of the vehicle during snowfall can be improved.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 is a block diagram of a vehicle lamp according to an
embodiment;
[0012] FIG. 2A illustrates a camera image IMG;
[0013] FIG. 2B illustrates a light distribution pattern PTN;
[0014] FIG. 3A is an enlarged view of a shaded portion;
[0015] FIG. 3B is an enlarged view of a shaded portion;
[0016] FIG. 3C is an enlarged view of a shaded portion;
[0017] FIG. 4 is a flowchart describing control of margin regions
based on positions;
[0018] FIG. 5 is a photograph taken from a traveling vehicle during
snowfall;
[0019] FIG. 6A illustrates a camera image IMG;
[0020] FIG. 6B illustrates a light distribution pattern PTN;
and
[0021] FIG. 7 is a block diagram of a vehicle lamp according to an
example.
DETAILED DESCRIPTION
Overview of Embodiment
[0022] A vehicle lamp according to an embodiment disclosed in the
present specification includes: a light distribution controller,
configured to generate a light distribution pattern including
shaded portions in which margin regions are added around snow
particles; and a variable light distribution lamp, which is capable
of generating a beam having an intensity distribution corresponding
to the light distribution pattern. In such a lamp, if the margin
regions are large, a capability to follow the snow particles is
improved, but surrounding regions of the snow particles are
darkened and visibility is thus reduced. On the contrary, if the
margin regions are small, the visibility is improved since beams
can be irradiated around the snow particles, but the capability to
follow the snow particles is reduced. Therefore, by controlling the
margin regions according to situations, a balance can be achieved
between the capability to follow and the visibility.
[0023] At least one of sizes and shapes of the margin regions may
be set according to positions of the snow particles. Trajectories
of the snow particles during traveling move radially from a
vanishing point. Apparent lengths of the trajectories of the snow
particles (amounts of movement per unit time) become longer when
the snow particles become closer to a given vehicle, that is,
farther from the vanishing point. Therefore, the margin regions may
become larger in a case where the snow particles become farther
from the vanishing point. Accordingly, a capability to follow snow
particles that are close to the given vehicle can be improved.
[0024] Since snow falls from a sky, the vanishing point of the snow
particles is located above an image. Therefore, the sizes of the
margin regions may become smaller in a case where positions of the
snow particles become higher and may become larger in a case where
the positions of the snow particles become lower. Accordingly,
control can be simplified.
[0025] The sizes and shapes of the margin regions may reflect a
vehicle speed. Accordingly, the capability to follow the snow
particles can be improved during high-speed traveling, and the
visibility can be improved during low-speed traveling or
parking.
[0026] The sizes and shapes of the margin regions may reflect an
output of a raindrop sensor. It is difficult to accurately detect
sizes of the snow particles. Therefore, it can be assumed that
there is a correlation between the output of the raindrop sensor
and the sizes of the snow particles, and the sizes of the snow
particles can be reflected by sizes of shaded portions through
adjusting the margin regions.
[0027] In a range in which an object to be noticed (hereinafter,
referred to as a noticed object) is present, such as a preceding
vehicle, an oncoming vehicle, or a pedestrian, it may be preferable
to prioritize visibility of the noticed object instead of the
capability to follow the snow particles. On the other hand, in a
range in which the noticed object is absent, for example, a
background is the sky, or in a range in which the object is located
far away, there is no problem in giving priority to the capability
to follow. Therefore, the sizes of the margin regions may be
reduced in the range in which the noticed object is present.
Embodiment
[0028] The above is an overview of the vehicle lamp. Hereinafter,
the present invention will be described based on a preferred
embodiment with reference to the drawings. The embodiment is not
intended to limit the invention and all the features and
combinations thereof described in the embodiment are not
necessarily essential to the invention. The same or equivalent
components, members, and processes shown in the drawings are
denoted by the same reference numerals, and a repetitive
description thereof will be omitted. In addition, the scale and
shape of each part shown in each of the drawings are set for
convenience to simplify the description, and are not to be
interpreted as limitations unless otherwise specified. When the
terms "first", "second" and the like are used in the present
specification and claims, the terms are not intended to represent
any order or importance, and are intended to distinguish one
configuration from another.
[0029] FIG. 1 is a block diagram of the vehicle lamp according to
the embodiment. The vehicle lamp 100 includes a variable light
distribution lamp 110 and a light distribution controller 140.
[0030] The variable light distribution lamp 110 is a white light
source, which receives data indicating a light distribution pattern
PTN from the light distribution controller 140, emits a beam L3
having an intensity distribution (beam profile) corresponding to
the light distribution pattern PTN, and forms an illuminance
distribution corresponding to the light distribution pattern PTN in
front of the vehicle. A configuration of the variable light
distribution lamp 110 is not particularly limited, and may include,
for example, a semiconductor light source, such as a laser diode
(LD) or a light emitting diode (LED), and a lighting circuit for
driving and lighting the semiconductor light source. The variable
light distribution lamp 110 may include a matrix-type pattern
forming device, such as a digital mirror device (DMD) or a liquid
crystal device, so as to form the illuminance distribution
corresponding to the light distribution pattern PTN. The variable
light distribution lamp 110 has a resolution enough to shade only
the portions of the snow particles.
[0031] The light distribution controller 140 dynamically and
adaptively controls the light distribution pattern PTN supplied to
the light distribution variable lamp 110. The light distribution
pattern PTN is recognized as a two-dimensional illuminance
distribution of a white light irradiation pattern 902 formed by the
variable light distribution lamp 110 on a virtual vertical screen
900 in front of the given vehicle. The light distribution
controller 140 can be configured by a digital processor, or may be
configured by a combination of a microcomputer (including a CPU)
and a software program, by a field programmable gate array (FPGA)
or an application specified IC (ASIC), or the like.
[0032] In the present embodiment, the light distribution controller
140 detects the snow particles and generates the light distribution
pattern PTN in which the portions corresponding to the snow
particles are shaded. "Shading a certain portion" includes a case
where a luminance (illuminance) of the portion is set to zero and a
case where the luminance (illuminance) of the portion is
reduced.
[0033] A method for detecting the snow particles is not limited.
The light distribution controller 140 can detect the snow particles
by image processing based on a camera image IMG obtained by a
camera (not shown). A detection algorithm of the snow particles is
not particularly limited. The light distribution controller 140 may
detect the snow particles based on a plurality of consecutive
frames of the camera image IMG.
[0034] FIGS. 2A and 2B describe an operation of the vehicle lamp
100 of FIG. 1. FIG. 2A shows the camera image IMG, and FIG. 2B
shows the light distribution pattern PTN corresponding to the
camera image of FIG. 2A. Snow particles 6, a person 8, and a
vehicle 10 are shown in the camera image IMG. The light
distribution controller 140 detects the snow particles 6 from the
camera image IMG and shades corresponding portions 7 (referred to
as shaded portions) of the light distribution pattern PTN.
[0035] The light distribution controller 140 may perform so-called
ADB control, and in this case, when a target that should not be
given glare to is detected, such as the vehicle 10, a corresponding
portion 11 is also shaded
[0036] The light distribution pattern PTN is updated at a rate of,
for example, 30 fps or more, and the shaded portions 7 can be moved
following the snow particles 6. Accordingly, reflected light of the
snow particles 6 can be reduced, and visibility of a front can be
improved.
[0037] FIGS. 3A to 3C are enlarged views of the shaded portions 7.
The shaded portions 7 include portions X of the snow particles 6
and margin regions Y added around the portions
[0038] X. The shaded portions 7 can have rectangular shapes which
are longer in moving directions of the snow particles and shorter
in directions perpendicular to the moving directions of the snow
particles (indicated by arrows in the drawings). In the present
embodiment, at least one of the sizes and shapes of the margin
regions Y are variable, and are dynamically and/or adaptively
controlled. In a shaded portion 7 of FIG. 3A, a size of a margin
region Y is the smallest, and the sizes of the margin regions Y
sequentially become larger in FIGS. 3B and 3C. In FIGS. 3A to 3C,
lengths W of the margin regions Yin short directions are fixed, and
lengths L of the margin regions Y in longitudinal directions are
variable.
[0039] Hereinafter, specific control of the margin regions Y will
be described.
[0040] 1. Control Based on Position
[0041] At least one of the sizes and the shapes of the margin
regions Y can be variable according to positions of the snow
particles (shaded targets).
[0042] FIG. 4 is a flowchart describing control of margin regions
based on the positions. The camera captures an image of a front of
the vehicle (S100). Then, the snow particles are detected based on
the camera image (S102). Then, the size and the shape of the margin
region Y is set for each snow particle depending on a position of
the snow particle (S104). Then, the shaded regions are set and the
light distribution pattern is updated (S106). This operation is
repeated.
[0043] FIG. 5 is a photograph taken from a traveling vehicle during
snowfall. The snow particles move radially from a certain vanishing
point DP. In the photograph, the snow particles are observed as
trajectories during exposure time. Lengths of the trajectories are
apparent movement distances per unit time of the snow particles
(apparent speeds). A trajectory becomes shorter in a case where a
snow particle becomes closer to the vanishing point DP, and a
trajectory becomes longer if a snow particle becomes farther from
the vanishing point DP. Therefore, the margin regions Y may become
larger in a case where the snow particles become farther from the
vanishing point. Accordingly, the capability to follow can be
improved.
[0044] The vanishing point DP may be detected by the image
processing based on traveling situations. Alternatively, since the
snow falls from the sky, the vanishing point DP of the snow
particles may be fixed. It may be considered that the snow
particles becomes closer to the vanishing point DP in a case where
the positions of the snow particles become higher in the image, and
the snow particles become farther from the vanishing point DP in a
case where the positions of the snow particles become lower in the
image. Based on this assumption, the sizes of the margin regions Y
may become smaller in a case where the positions of the snow
particles become higher and may become larger in a case where the
positions of the snow particles become lower. Accordingly, the
control can be simplified.
[0045] In a range in which an object to be noticed (hereinafter,
referred to as a noticed object) is present, such as a preceding
vehicle, an oncoming vehicle, or a pedestrian, it may be preferable
to prioritize visibility of the noticed object instead of the
capability to follow the snow particles. On the other hand, in a
range in which the noticed object is absent, for example, a
background is the sky, or in a range in which the object is located
far away, there is no problem in giving priority to the capability
to follow. Therefore, the sizes of the margin regions may be
reduced in the range in which the noticed object is present.
[0046] FIGS. 6A and 6B describe improvement of the visibility with
respect to the noticed object. FIG. 6A shows the camera image IMG,
and FIG. 6B shows the light distribution pattern PTN. There is a
high possibility that a noticed object OBJ is present in a region B
including a road. On the contrary, since a background of a region A
above the region B is the sky (or a distant area), it can be said
that there is a low possibility that the noticed object is
present.
[0047] Therefore, the light distribution controller 140 may divide
the region B in which the noticed object may be present and the
region A in which the noticed object may be absent, control the
margin regions corresponding to the positions of the snow particles
in the region A, and exclude the region B from the control. In the
region B, the sizes of the margin regions are preferably small. In
other words, the region B may be excluded from shading control
based on the snow particles.
[0048] 2. Control Based on Traveling Situation
[0049] In addition to the positions of the snow particles, the
traveling situation can be reflected in the control of the margin
regions. As an example, the apparent speeds of the snow particles
become faster if a vehicle speed v becomes faster, and becomes
slower if the vehicle speed v becomes slower. Therefore, the
lengths L of the margin regions may be controlled according to the
vehicle speed v. When a y coordinate of a snow particle is referred
to as y while the vehicle speed is referred to as v, a length L of
a margin region can be expressed by a function f(y,v).
L=f(y,v)
[0050] The light distribution controller 140 may calculate a value
of the function f(y,v) or may have a lookup table.
[0051] In addition to the vehicle speed or instead of the vehicle
speed, an output of a raindrop sensor may be reflected in the
control of the margin regions. When the output of the raindrop
sensor is large, that is, when an amount of snowfall is large, the
lengths L of the margin regions may be relatively larger. It is
difficult to accurately detect the sizes of the snow particles only
based on the camera image IMG. Therefore, it can be assumed that
there is a correlation between the output of the raindrop sensor
and the sizes of the snow particles, and the sizes of the snow
particles can be reflected by sizes of shaded portions through
adjusting the margin regions.
[0052] When the amount of snowfall is large, that is, when the
number of the snow particles is large, if one shaded portion 7 is
set for each of the snow particles, a computation cost is
increased. Therefore, when the output of the raindrop sensor is
large, through enlarging the lengths L (and/or widths W) of the
margin regions, there is an advantage that a plurality of snow
particles can be collectively processed in one shaded portion
7.
[0053] Next, a method for detecting the snow particles will be
described. FIG. 7 is a block diagram of a vehicle lamp 100A
according to an example. The vehicle lamp 100A includes an infrared
illumination device 120 and an infrared camera 130. The infrared
illumination device 120 and the infrared camera 130 may be
incorporated in a housing (lamp body) of the vehicle lamp 100 or
may be externally attached. The infrared illumination device 120
may be incorporated in the housing, and the infrared camera 130 may
be mounted on an inner side of a room mirror.
[0054] The infrared illumination device 120 is a probe light source
that irradiates infrared probe light L1 to the front of the
vehicle. The probe light L1 may be near-infrared light or light
having a longer wavelength. The infrared camera 130 images
reflected light L2 of the probe light L1 reflected by an object 2
in front of the vehicle. The infrared camera 130 should be
sensitive to at least a wavelength region of the probe light L1,
and is preferably insensitive to visible light.
[0055] The light distribution controller 140 detects the snow
particles by the image processing based on the camera image IMG
obtained by the infrared camera 130.
[0056] Advantages of the vehicle lamp 100A will be described. When
white (visible) probe light is used to detect the snow particles,
the snow particles shine whitely and generate glare each time the
probe light is irradiated, resulting in a poor visual field.
According to the present embodiment, since infrared rays are used
as the probe light, there is an advantage that the glare can be
prevented.
[0057] Since the infrared rays are used as the probe light, there
is an advantage that it is difficult for the driver to recognize
the probe light even when the probe light is continuously
irradiated. Therefore, it is possible to follow and detect snow
particles moving at high speeds.
[0058] The present invention was described above based on the
embodiment. It is to be understood by those skilled in the art that
this embodiment is only an example, and various modifications can
be made to combinations of respective components and respective
processing processes, and such modifications are also within the
scope of the present invention. Hereinafter, such modifications
will be described.
Modification 1
[0059] Although the shading control of the snow particles was
described in the embodiment, raindrops may also be subjected to the
shading control.
Modification 2
[0060] In the embodiment, only the lengths L of the margin regions
are variable, but in addition to this, the widths W may also be
variable, and the shapes of the margin regions may also be
variable.
Modification 3
[0061] In the embodiment, the infrared rays are used as the probe
light, but the present invention is not limited thereto. It is also
possible to use the beam L3 emitted by the variable light
distribution lamp 110 as the probe light to detect the snow
particles. In this case, glare is given to the driver if
irradiation time of the probe light is long, so that emission time
of the probe light may be shortened to such a degree that the
reflected light L2 cannot be detected by the driver.
Modification 4
[0062] Although the present invention was described with specific
words and phrases based on the embodiment, the embodiment merely
shows an aspect of principles and applications of the present
invention, and various changes of modifications and configurations
may be made in the embodiment without departing from the inventive
concept of the invention as defined in the claims.
[0063] 100 Vehicle Lamp
[0064] 110 Variable Light Distribution Lamp
[0065] 120 Infrared Illumination Device
[0066] 130 Infrared Camera
[0067] 140 Light Distribution Controller
[0068] L1 Probe Light
[0069] L2 Reflected Light
[0070] L3 Beam
* * * * *