United States Patent [19J
`Kobayashi
`
`I 1111111111111111 11111 1111111111 111111111111111 1111111111111111 Ill lllll llll
`US006049749A
`[11] Patent Number:
`[45] Date of Patent:
`
`6,049,749
`Apr. 11, 2000
`
`[54] LIGHTING DEVICE FOR A VEHICLE
`
`FOREIGN PATENT DOCUMENTS
`
`[75]
`
`Inventor: Shoji Kobayashi, Shizuoka, Japan
`
`[73] Assignee: Koito Manufacturing Co., Ltd.,
`Tokyo, Japan
`
`[21] Appl. No.: 08/989,415
`
`[22] Filed:
`
`Dec. 12, 1997
`
`[30]
`
`Foreign Application Priority Data
`
`Dec. 13, 1996
`
`[JP]
`
`Japan .................................... 8-353006
`
`Int. Cl.7 ...................................................... G06F 17/00
`[51]
`[52] U.S. Cl. .............................. 701/49; 701/36; 362/466;
`362/37; 362/276; 340/469
`[58] Field of Search ........................ 701/49, 36; 362/272,
`362/276, 466, 494, 540, 541, 544, 465,
`524, 37, 40; 340/469, 471, 472
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,663,696
`4,733,333
`5,060,120
`5,068,768
`5,237,306
`5,343,371
`5,379,196
`5,404,278
`5,412,543
`5,426,294
`5,436,807
`5,497,306
`5,562,336
`5,588,733
`5,660,454
`5,879,074
`5,931,572
`
`5/1987 Miyazaki et al. ......................... 362/80
`3/1988 Shibata et al. ............................ 362/40
`10/1991 Kobayashi et al. ....................... 362/61
`11/1991 Kobayashi et al. ....................... 362/61
`8/1993 Adell ....................................... 340/469
`8/1994 Kobayashi et al. ....................... 362/61
`1/1995 Kobayashi et al. ....................... 362/61
`4/1995 Shibata et al. ......................... 362/83.3
`5/1995 Kobayashi et al. ....................... 362/66
`6/1995 Kobayashi et al. ..................... 250/226
`7/1995 Kobayashi ................................ 362/41
`3/1996 Pastrick ................................... 362/494
`10/1996 Gotou ...................................... 362/466
`12/1996 Gotou ........................................ 362/37
`8/1997 Mori et al. .............................. 362/466
`3/1999 Pastrick ................................... 362/494
`8/1999 Gotoh ...................................... 362/466
`
`43 27 780
`196 01 572
`196 02 622
`
`3/1994 Germany ..................... G08G 1/0968
`8/1996 Germany ......................... B60Q 1/12
`8/1996 Germany ......................... B60Q 1/06
`
`Primary Examiner-Jacques H. Louis-Jacques
`Attorney, Agent, or Firm-Sughrue, Mion, Zinn, Macpeak
`& Seas, PLLC
`
`[57]
`
`ABSTRACT
`
`A lighting device in which the vehicle advancing direction
`at which a driver aims is predicted, and the irradiating
`direction and irradiating range of a lighting device are
`controlled by comparing the result of the prediction to the
`information of the profile of a road on which the vehicle is
`running at present. The lighting device (1) includes a road
`profile calculating device (2) for finding an advancing
`direction of the vehicle in the case where the vehicle
`advances along a road on which the vehicle is running at
`present, in accordance with the map information including
`the road profile and the present position information of the
`vehicle; and a vehicle advancing direction predicting device
`(3) for predicting an advancing direction of the vehicle
`intended by a driver, by an operation signal given by the
`driver or detection information of the vehicle running state.
`The irradiation controller device ( 4) compares the direction
`data of the road profile calculating device (2) with the
`direction data of the vehicle advancing direction predicting
`device (3), the irradiation control of the lighting device (5)
`is conducted by the road profile in accordance with the
`direction data of the road profile calculating device (2) when
`a difference between them is in an allowable range, and the
`irradiation control of the lighting device (5) is conducted by
`the direction data of the vehicle advancing direction pre(cid:173)
`dicting device (3) when the difference between them is out
`of the allowable range.
`
`10 Claims, 9 Drawing Sheets
`
`2
`
`ROAD PROFILE
`CALCULATING MEANS
`
`VEHICLE ADVANCING
`3 DIRECTION PREDICTING MEANS
`
`7
`
`VEHICLE SPEED
`DETECTING MEANS
`
`4
`
`IRRADIATION
`CONTROL
`MEANS
`
`5
`
`6
`
`DRIVE
`MEANS
`
`8
`
`INDICATING
`MEANS
`
`PCNA Ex. 1008
`U.S. Patent No. 9,955,551
`
`
`

`

`U.S. Patent
`
`Apr. 11, 2000
`
`Sheet 1 of 9
`
`6,049,749
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`U.S. Patent
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`Apr. 11, 2000
`
`Sheet 2 of 9
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`6,049,749
`
`FIG. 2
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`A
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`U.S. Patent
`
`Apr. 11, 2000
`
`Sheet 3 of 9
`
`6,049,749
`
`FIG. 4
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`FIG. 6
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`DRIVE
`I .. I CIRCUIT-~
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`DEVICE OF COMMUNICATION
`BETWEEN ROAD AND VEHICLE
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`TRACK DISPLAY/PRESENT VEHICLE
`POSITION CALCULATING DEVICE
`
`13~ STEERING SENSOR
`
`14
`
`15
`
`16
`
`VEHICLE SPEED
`SENSOR
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`DIRECTION INDICATION
`CHANGEOVER SWITCH
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`AUTOMATIC CONTROL
`CHANGEOVER SWITCH
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`

`

`U.S. Patent
`
`Apr. 11, 2000
`
`Sheet 5 of 9
`
`6,049,749
`
`FIG. 7
`
`18L (18A)
`
`DRIVE SECTION
`
`26
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`26 1
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`FIG. 8
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`

`

`U.S. Patent
`
`Apr. 11, 2000
`
`Sheet 6 of 9
`
`6,049,749
`
`FIG. 9
`
`INTERLOCKING MODE OF
`COMMUNICATION BETWEEN
`ROAD AND VEHICLE
`
`CALCULATION OF PRESENT
`VEHICLE POSITION
`
`S1
`
`MEASUREMENT OF ELAPSING TIME
`OBTAINING OF ROAD PROFILE
`
`S2
`
`NO
`
`PREDICTION OF VEHICLE
`ADVANCING DIRECTION
`
`S4
`
`S5
`
`PREDICTION OF VEHICLE
`ADVANCING DIRECTION
`
`NO
`
`NO
`
`YES
`
`S10
`
`IRRADIATION CONTROL
`IN ACCORDANCE WITH
`THE PREDICTION OF
`ADVANCING DIRECTION
`
`YES
`
`IRRADIATION CONTROL
`IN THE BRANCH MODE
`
`S9
`
`S8
`
`IRRADIATION CONTROL
`IN THE NON-BRANCH MODE
`
`RETURN
`
`

`

`U.S. Patent
`U.S. Patent
`
`Apr. 11, 2000
`Apr. 11, 2000
`
`Sheet 7 of 9
`Sheet 7 of 9
`
`0
`
`6,049,749
`6,049,749
`
`
`
`
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`

`

`U.S. Patent
`
`Apr. 11, 2000
`
`Sheet 8 of 9
`
`6,049,749
`
`FIG. 11
`
`L2
`
`(INTERSECTION)
`
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`
`

`

`GUIDE ROUTE
`SETTING SECTION
`
`2 9
`\
`
`36
`I
`MAP INFORMATION
`OUTPUTTING SECTION
`
`FIG. 12
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`DISPLAY
`SECTION
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`32
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`SECTION
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`CALCULATING
`SECTION
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`33
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`VEHICLE SPEED
`SENSOR
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`STEERING SENSOR
`
`15- DIRECTION INDICATION
`CHANGEOVER SWITCH
`
`16~
`
`AUTOMATIC CONTROL
`CHANGEOVER SWITCH
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`

`

`1
`LIGHTING DEVICE FOR A VEHICLE
`
`6,049,749
`
`2
`control of the lighting device is conducted by referring the
`result of prediction to the information of the profile of a road
`on which the vehicle is running at present.
`In order to solve the above problems, the present inven-
`tion is directed to a lighting device for vehicle use compris(cid:173)
`ing: an irradiation control means for controlling the irradia(cid:173)
`tion of a lighting device for vehicle use in accordance with
`a road profile, operation of the vehicle and running condition
`of the vehicle; a road profile calculating means for finding an
`10 advancing direction of the vehicle in the case where the
`vehicle advances along a road on which the vehicle is
`running at present, in accordance with the map information
`including the road profile and the present position informa(cid:173)
`tion of the vehicle; and a vehicle advancing direction
`predicting means for predicting an advancing direction of
`15 the vehicle intended by a driver, by an operation signal given
`by the driver or detection information of the vehicle running
`state, wherein the irradiation control means compares the
`direction data of the road profile calculating means with the
`direction data of the vehicle advancing direction predicting
`20 means, the irradiation control of the lighting device is
`conducted by the road profile in accordance with the direc(cid:173)
`tion data of the road profile calculating means when a
`difference between them is in an allowable range, and the
`irradiation control of the lighting device is conducted by the
`25 direction data of the vehicle advancing direction predicting
`means when the difference between them is outside of the
`allowable range. According to the present invention, the
`direction data made by the road profile calculating means is
`compared with the direction data made by the vehicle
`advancing direction predicting means. Due to the above
`comparison, when the vehicle advancing direction at which
`the driver aims coincides with the profile of a road, irradia(cid:173)
`tion control of the lighting device is conducted in accor(cid:173)
`dance the profile of the road. When the vehicle advancing
`direction at which the driver aims does not coincide with the
`profile of the road, it possible to conduct irradiation control
`of the lighting device in accordance with the vehicle advanc(cid:173)
`ing direction at which the driver aims.
`
`5
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention relates to a lighting device for
`vehicle use which conducts irradiation control of the lighting
`device in accordance with a road profile, vehicle operation
`and vehicle running condition.
`2. Background
`Conventionally, there is known a device by which an
`irradiating direction of a lighting device for a vehicle is
`changed in accordance with a steering angle of the vehicle.
`In this type device, the following problems may be encoun(cid:173)
`tered. As long as a steering member such as a steering wheel
`is not actually operated, the irradiating direction of the
`lighting device can not be changed. Therefore, it is impos(cid:173)
`sible to adjust the irradiating direction of the lighting device
`into a direction in which the vehicle is advancing, just prior
`to a point in time at which the vehicle advances to a curved
`road.
`In order to solve the above problems, there is proposed a
`device in which the navigation system (route guidance
`system) is used and the irradiating direction of the lighting
`device for vehicle use is changed before the advance of the
`vehicle to a curved road in accordance with the map infor(cid:173)
`mation including profile data of the road and also in accor(cid:173)
`dance with the positional information of the vehicle on a
`map provided in the vehicle. However, the above device is
`disadvantageous in that the irradiation control can not be 30
`completely conducted when the vehicle is on a road which
`is not included in the map information and also when the
`vehicle advances to a route not scheduled at an intersection.
`That is, when the navigation system can not be used or the
`vehicle advancing direction is changed at an intersection, 35
`priority is given to the driver's intention.
`In order to solve the above problems, there is known a
`device in which priority is given to the irradiation control of
`the lighting device for vehicle use based on the operation of
`a direction indicator and the detection of a steering angle, 40
`over the irradiation control based on the map information.
`It is possible to conduct irradiation control of the lighting
`device irrespective of the navigation system in the following
`manner. For example, a signal sent out from a direction
`indicator of the vehicle is discriminated, and the irradiating 45
`direction of the lighting device is changed in a direction of
`a track to which the signal is indicated. Alternatively, there
`is provided a detecting means for detecting a steering angle,
`and the irradiating direction of the lighting device is changed
`when a steering angle detected by the detecting means is 50
`larger than a predetermined value.
`However, when the above method is adopted, the follow(cid:173)
`ing problems may be encountered. Since priority is always
`given to the operation of the direction indicator of the
`vehicle and the result of detection of the steering wheel, 55
`when a driver mistakenly emits a signal of the direction
`indicator in an erroneous direction, the irradiating direction
`of the lighting device is changed in a direction at which the
`driver is not aiming. Also, when priority is excessively given
`to the detection of the detected steering angle, it become 60
`impossible to accomplish the primary object of changing the
`irradiating direction of the lighting device before the vehicle
`enters a curved road.
`
`SUMMARY OF THE INVENTION
`According to the present invention, the vehicle advancing
`direction at which a driver aims is predicted, and irradiation
`
`65
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a block diagram showing the essential structure
`of the lighting device for vehicle use according to the present
`invention;
`FIG. 2 is a schematic illustration showing the selection of
`a tack at a branch on a road;
`FIG. 3 is a schematic illustration showing the irradiation
`angle of a lighting device on a straight road;
`FIG. 4 is a schematic illustration showing the irradiating
`angle of a lighting device at an intersection;
`FIG. 5 is a schematic illustration showing a relation
`between the distance from the intersection to the vehicle and
`the irradiating angle;
`FIG. 6 is a view showing the first example of the present
`invention together with FIGS. 7 to 11, wherein this view is
`a block diagram showing the device structure;
`FIG. 7 is a schematic illustration showing the arrange(cid:173)
`ment of a lighting device;
`FIG. 8 is a schematic illustration showing an example of
`the change in a luminous intensity distribution in a light
`distribution pattern;
`FIG. 9 is a flow chart showing a procedure in the
`interlocking mode of communication between road and
`vehicle;
`FIG. 10 is a schematic illustration for explaining irradia(cid:173)
`tion control of a lighting device when a vehicle runs on a
`curved road;
`
`

`

`6,049,749
`
`3
`FIG. 11 is a schematic illustration of irradiation control
`conducted on a lighting device at a branch; and
`FIG. 12 is a circuit block diagram showing an arrange(cid:173)
`ment of the device of the second example of the present
`invention.
`
`DETAILED DESCRIPTION OF IBE
`INVENTION
`FIG. 1 is a view showing an essential structure of the
`lighting device 1 for vehicle use according to the present
`invention. The lighting device 1 includes: a road profile
`calculating means 2, vehicle advancing direction predicting
`means 3, irradiation control means 4 and light device (e.g.,
`headlamp) 5. The irradiating direction and irradiating range
`of the lighting device 5 are directly controlled by the
`irradiating control means 4 or indirectly controlled via the
`drive means 6. In the case of a lighting device used for an
`automobile, examples of the lighting device 5 are a head
`lamp, fog lamp and corner lamp.
`The road profile calculating means 2 is provided for
`finding an advancing direction of a vehicle in the case where
`the vehicle advances along a road on which the vehicle is
`running at present in accordance with the map information
`including the road profile and the present position informa-
`tion of the vehicle. An output signal of the road profile
`calculating means 2 is sent to the irradiation control means
`4.
`
`When the road map information is inputted, it is possible
`to use the navigation system, which is called "Car Naviga(cid:173)
`tion System", utilizing electric waves sent from GSP ( Global
`Positioning System) satellite, and it is also possible to use
`the communication system for conducting communication
`between the road and vehicle. In the former navigation
`system, according to the detection signals of the gyrosensor
`and vehicle speed sensor, the electric wave information sent
`from GSP satellite received by GSP receiver and the map
`information recorded on a recording medium such as
`CD-ROM, it is possible to display the present position of the
`vehicle on a road map, and it is also possible to guide the
`vehicle along a scheduled route to the destination. Accord(cid:173)
`ing to the latter communication between the road and
`vehicle, information about the position of the vehicle and
`road profile (including a taper and radius of curvature of the
`road) can be obtained via beacons (poles used for commu(cid:173)
`nication between the vehicles and road) which are arranged
`in central separation zones and road side zones of trunk lines
`at regular intervals and also arranged at primary corners and
`intersections in city areas and mountain areas in which many
`obstacles in correspondence are located.
`Further, a system in which the auxiliary channels of FM
`broadcasting multisystem is used can be adopted to input the
`road map information. As long as the road profile informa(cid:173)
`tion and the present position information of the vehicle can
`be obtained, it is possible to find an advancing direction of
`the vehicle when the vehicle advances on the road and it is
`also possible to judge whether or not a branch such as an
`intersection is located ahead.
`The vehicle advancing direction predicting means pre(cid:173)
`dicts an advancing direction of the vehicle at which the 60
`driver aims, by an operation signal given by the driver of the
`vehicle or a detecting information of the vehicle running
`condition. The result of prediction is sent to the irradiation
`control means 4.
`Examples of information used for predicting the vehicle 65
`advancing direction are: a direction indicating signal given
`to the direction indicator, detection signal of the steering
`
`25
`
`4
`angle (steering angle of the steering wheel), vehicle speed
`detection signal, acceleration detection signal, detection
`signal of the vehicle posture ( output signal of the vehicle
`height sensor), and scheduled route to the destination that is
`5 set in the navigation system having a route guide function.
`According to the information described above, the vehicle
`advancing direction predicting means 3 synthetically pre(cid:173)
`dicts a vehicle advancing direction at which the driver aims.
`For example, without relying only on the direction indicat-
`10 ing signal, a change in the steering angle is detected every
`moment from a point in time at which the direction indi(cid:173)
`cating signal is sent out, and it is judged by a change in the
`vehicle posture, vehicle speed, vehicle acceleration and
`vehicle running condition whether or not a preliminary
`15 behavior to turn in a direction indicated by the direction
`indicating signal can be recognized, and the vehicle move(cid:173)
`ment can be predicted. That is, when a change in the
`behavior is detected before the vehicle changes its track, and
`a direction extrapolated as an extension of the change in the
`20 behavior is discriminated as an advancing direction of the
`vehicle.
`An example of the prediction of the vehicle advancing
`direction is explained as follows using a simplified model.
`Concerning the direction indicator, a judgment of the right
`and left is conducted, and also it is detected whether or not
`there is an indication given by the driver. A direction of the
`change in the steering angle is discriminated and also an
`amount of change in the steering angle is discriminated. The
`direction of acceleration is discriminated and also an inten-
`30 sity of acceleration is discriminated. First, when a direction
`indicating signal is given, it is temporarily predicted that the
`advancing direction is to be changed in the direction con(cid:173)
`cerned. When the change in the steering angle in a prede(cid:173)
`termined period of time is large or the vehicle speed is
`35 reduced exceeding a predetermined range, it is judged that
`the prediction is correct. When the change in the steering
`angle in a predetermined period of time is small or the
`vehicle speed is not reduced, the above prediction is
`corrected, and it is judged that the driver has no intention of
`40 changing the track. In the case where the change in the
`steering angle in a predetermined period of time is large or
`the vehicle speed is suddenly reduced although there is no
`direction indicating signal, it is judged that the driver has an
`intention of changing the tack. In this connection, concern-
`45 ing the importance of the basic information used for
`prediction, it is not necessary that all pieces of information
`must be uniform. Of course, in accordance with the value of
`information, it can be weighted.
`When the vehicle advancing direction is predicted, it is
`50 possible to utilize information obtained from the above road
`profile data. For example, in the case of a road on which a
`branch is located ahead, a distance from the present vehicle
`position to the branch is calculated, and a change of the
`steering angle is detected as the distance is shortened. When
`55 the change of the steering angle is small, it can be predicted
`that the vehicle advances straight. When the change of the
`steering angle is large, it can be predicted that the driver has
`an intention of changing the track in the changing direction
`of the steering angle.
`When it is predicted that the vehicle advancing direction
`is the same as the direction of the road on which the vehicle
`is running at present, the irradiation control means 4 con(cid:173)
`ducts irradiation control of the lighting device in accordance
`with the road profile. When it is discriminated that the
`predicted vehicle advancing direction is different from the
`direction of the road on which the vehicle is running at
`present, irradiation control of the lighting device 5 is con-
`
`

`

`6,049,749
`
`5
`ducted in accordance with the predicted vehicle advancing
`direction. That is, the irradiation control means 4 compares
`the direction data of the road profile calculating means 2
`with the direction data of the vehicle advancing direction
`predicting means 3. When a difference between them is in an 5
`allowable range, irradiation control of the lighting device 5
`is conducted in accordance with the road profile based on the
`direction data of the road profile calculating means 2. When
`a difference between them is out of an allowable range,
`irradiation control of the lighting device 5 is conducted in 10
`accordance with the predicted vehicle advancing direction
`based on the direction data of the vehicle advancing direc(cid:173)
`tion predicting means 3.
`Concerning the comparison of direction data, for
`example, it is possible to use a method in which a difference 15
`of the angle between two directions is compared with a
`reference value of judgment. Also, it is possible to use a
`method in which a predetermined angle width is set for two
`angles and crossing of the two angles is compared with a
`reference value of judgment. Concerning the reference value
`and the angle width used in this case, they may be constant
`values, or alternatively they may be changed in accordance
`with other factors such as a vehicle speed.
`When it is discriminated that there is a branch ahead on
`a road, it is preferable to discriminate whether the driver
`wants to select one of the plurality of selections at the branch
`or to advance to a track not included in the selections at the
`branch.
`For example, it is possible to consider a case shown in
`FIG. 2. In this case, branch Pis located ahead on road Rt. At
`branch P, the road branches into roads A to D, wherein roads
`A to D shown by solid lines are roads included in the map
`information, and road E (shown by a broken line) is a road
`not included in the map information. When the driver selects
`one of roads A to D at branch P, the road profile calculating
`means 2 sends four groups of data indicating the predicted
`vehicle advancing directions to the irradiation control means
`4, and these groups of data are compared with the direction
`data sent from the vehicle advancing direction predicting
`means 3. By this comparison, it is possible to select one of 40
`the tracks at branch P, because the driver may select a group
`of data, which is closest to the direction data sent from the
`vehicle advancing direction predicting means 3, from the
`four data groups sent from the road profile calculating means
`2. However, in the case where the driver selects road E not 45
`included in the map information, the four groups of direction
`data sent from the road profile calculating means 2 are not
`close to the direction data sent from the vehicle advancing
`direction predicting means 3. Accordingly, the irradiation
`control means 4 conducts irradiation control of the lighting
`device 5 in accordance with the direction data sent from the
`vehicle advancing direction predicting means 3 in this case.
`When the branch is discriminated, it is possible to make
`judgment indiscriminately, however, it is preferable to make
`judgment whether or not it can be assumed to be a branch,
`in accordance with the scale of the branch. The branch may
`be discriminated as follows. For example, the following
`setting may be adopted. Only an intersection provided with
`a signal machine is discriminated to be a branch, or alter(cid:173)
`natively according to the grade of a road and the circum(cid:173)
`stances of an intersection, only an intersection at which
`trunk roads such as national highways and state highways
`cross each other is discriminated to be a branch. When the
`branch is discriminated as described above, the driver may
`determine its setting by manual operation while a plurality
`of levels are set. Alternatively, discrimination may be auto(cid:173)
`matically conducted by the vehicle in such a manner that
`
`6
`only a large scale intersection is discriminated to be a
`branch, for example, when the vehicle is running on a
`passing lane.
`Concerning the irradiation control, the following control
`factors are provided:
`(A) Irradiating direction
`(B) Irradiating range
`( C) Time to start control
`(D) Control speed
`First, concerning the control of the irradiating direction,
`the following two methods are provided:
`(A-I) Method of directing all of irradiation light in a
`predetermined direction; and
`(A-II) Method of directing a portion of irradiation light in
`a predetermined direction.
`The simplest method in the above item (A-I) is to direct
`an irradiation axis of the lighting device in a predetermined
`direction by rotating the entire lighting device about its axis.
`20 Another method is to direct an irradiation axis of the lighting
`device in a predetermined direction by controlling the pos(cid:173)
`ture of a member composing the lighting device such as a
`reflecting mirror, lens, light source and shielding member.
`According to the method described in item (A-II), irra-
`25 diation light is changed partially. Accordingly, it is possible
`to adopt a method in which the irradiation axis of only a
`specific lighting device is changed in the device composed
`of a plurality of lighting devices. For example, in an auto(cid:173)
`mobile provided with head lamps, fog lamps and corner
`30 lamps, the posture of the irradiation axis of one of the
`lighting devices or the postures of the irradiation axes of two
`of the lighting devices are controlled. Alternatively, it is
`possible to adopt a method of controlling the posture of one
`of the members composing the lighting device or the pos-
`35 tures of a plurality of members composing the lighting
`device. For example, the reflecting mirror is composed of a
`stationary reflecting mirror and a movable reflecting mirror,
`and the optical axis of the movable reflecting mirror is
`directed to a predetermined direction.
`Concerning the irradiating range control described in the
`above item (B), the following two methods are provided:
`(B-1) Method in which the irradiating ranges of a plurality
`of lighting devices are combined with each other; and
`(B-2) Method of changing an irradiating range by moving
`a portion of the components of the lighting device.
`First, the method described in item (B-1) is a method of
`controlling the irradiation range of a portion of lighting
`devices in which the overall irradiation range is formed by
`combining the irradiation ranges of a plurality of lighting
`50 devices. For example, there are provided two lighting
`devices, the irradiation ranges of which are different from
`each other, in a vehicle. The irradiation range of one of the
`lighting devices is fixed, and the irradiation range of the
`other lighting device is changed, for example, the irradiation
`55 range is extended in the transverse direction.
`According to the above method, when some of the plu(cid:173)
`rality of lighting devices, the irradiation ranges of which are
`different from each other, are selected, it is possible to obtain
`a desired irradiating range. However, it is necessary to use
`60 a large-scale device in the above method. For this reason,
`when it is necessary to simplify the structure of the device,
`the method of item (B-2) is preferably used.
`That is, when one of the members composing the lighting
`device or some members composing the lighting device are
`65 changed in the posture, it is possible to change the irradi(cid:173)
`ating range of the lighting device. For example, as a method
`of utilizing the movements of lenses, two lenses are arranged
`
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`

`6,049,749
`
`7
`so that the relative positional relation of the two lenses can
`adjusted, and diffusion of irradiating light is freely con(cid:173)
`trolled when the lens drive is controlled. Also, it is possible
`to adopt a method in which the irradiating range of the
`lighting device is changed when a shade provided for 5
`shading a portion of light emitted from a light source is
`moved. Also, the following various methods may be
`adopted. Only the light source is moved, the reflecting
`mirror and light source are moved, the lens and reflecting
`mirror are moved, or the lens and shade are moved together
`so that the irradiating range can be changed. It is possible to
`adopt various embodiments in accordance with the combi(cid:173)
`nation of the optical composing members of the lighting
`device.
`In this connection, concerning the control of extending
`and reducing the irradiating range, it is preferable to change
`the irradiating range in accordance with the speed and
`acceleration of the vehicle. The reason is that the range of
`vision of a driver is different between the case of high speed
`driving and the case of low speed driving, and also the range
`of vision of a driver is different between the case of constant
`speed driving and the case of reduced speed driving. It is
`preferable that the irradiating range is extended in the cases
`of low speed driving and sharply reduced speed driving as
`compared with other cases.
`Concerning the start time of control described in item (C),
`for example, in the case of a road having a branch, it is
`judged whether or not a distance from the branch to the
`vehicle or a time obtained when the distance is divided by
`a vehicle speed is in a predetermined range. It is possible to
`determine a point in time to start irradiation control such as
`a change of the irradiating direction ox irradiating range in
`accordance with the result of judgment. In this case, it is
`preferable that the reference value be changed in accordance
`with the vehicle speed and/or acceleration, because the way
`of access to a branch is different according to the vehicle
`speed. For example, when the vehicle speed is high, the
`irradiating range of the vehicle is changed at a position
`distant from the branch, or alternatively the irrad