United States Patent [19]
`Gotoh
`
`US005909949A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,909,949
`Jun. 8, 1999
`
`[54] HEAD LAMP DEVICE FOR VEHICLE
`
`314742 1/1991 Japan.
`
`[75] Inventor: Shinichiro Gotoh, Wako, Japan
`
`[73] Assignee: Honda Giken Kogyo Kabushiki
`Kaisha, Tokyo, Japan
`
`[21] Appl. No.2 08/868,184
`[22] Filed:
`Jun. 3, 1997
`[30]
`Foreign Application Priority Data
`
`11111. 3, 1996
`
`[JP]
`
`Japan .................................. .. 8140488
`
`Int. Cl.6 ..................................................... .. B60Q 1/08
`[51]
`[52] US. Cl. .......................... .. 362/37; 362/466; 362/465;
`315/82
`[58] Field of Search .............................. .. 362/37, 40, 466,
`362/524, 465; 315/79, 82
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`8/1989 Oikawa ................................. .. 362/466
`4,858,080
`9/1989 Hatanaka et al.
`362/466
`4,870,545
`6/1996 Takahashi et al.
`362/466
`5,526,242
`5,562,336 10/1996 661611.
`5,588,733 12/1996 661611.
`5,645,338
`7/1997 Kobayashi ............................ .. 362/466
`
`FOREIGN PATENT DOCUMENTS
`
`Primary Examiner—Thomas M. Sember
`Attorney, Agent, or F irm—Carrier, Blackman & Associates,
`PC; Joseph P. Carrier; William D. Blackman
`
`[57]
`
`ABSTRACT
`
`A head lamp device for a vehicle capable of changing a
`lighting region in front of the vehicle in right and left
`directions, in Which change of the lighting region is sup
`pressed so as not to give the driver a sense of incongruity
`When a steering Wheel is operated in one direction and then
`rapidly in the other as in case of counter-steering. The device
`comprises a lighting region changing mechanism for chang
`ing the lighting region of the head lamp; a steering angle
`sensor for detecting a steering angle; a turning movement
`detector for detecting a turning movement of the vehicle
`body in right and left directions; a ?rst lighting angle
`calculating mechanism for calculating a ?rst lighting angle
`based on the steering angle detected by the steering angle
`sensor; a second lighting angle calculating mechanism for
`calculating a second lighting angle based on the turning
`movement detected by the turning movement detector; a
`lighting angle deciding mechanism for deciding a ?nal
`lighting angle from the ?rst lighting angle and the second
`lighting angle; and a controller for controlling the lighting
`region changing means to change the lighting region on the
`basis of the ?nal lighting angle.
`
`62-77249
`
`4/1987 Japan .
`
`19 Claims, 6 Drawing Sheets
`
`812111180
`21 ~ ANGLE
`SDJSOR
`
`¢
`
`VEHICLE
`22- smzo
`SENSOR
`
`2a~ m RATE
`SENSOR
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`1°
`
`LIGHT DISTRIBUTION (IMROL 1100
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`RIGHT
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`8
`
`SL Corp. Exhibit 1007
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`

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`U.S. Patent
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`Jun. 8, 1999
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`Sheet 1 of6
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`5,909,949
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`

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`U.S. Patent
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`Jun. 8, 1999
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`Sheet 2 of6
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`5,909,949
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`FIG.3
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`2 E 2
`
`2 ANGLEmacmmc
`
`

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`U.S. Patent
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`Jun. 8, 1999
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`Sheet 3 of6
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`5,909,949
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`

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`U.S. Patent
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`Jun. 8, 1999
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`Sheet 4 of6
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`5,909,949
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`34
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`39
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`o0NmoLw1'm 5
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` LIGHI‘ DIS'lRIBUI‘I(N
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`FIG. 6
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`

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`U.S. Patent
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`Jun. 8, 1999
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`Sheet 5 of6
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`5,909,949
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`FIG. 7A
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`0 I Am
`
`(rad/s)
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`FIG. 7B
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`m.
`F
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`D _/
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`

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`U.S. Patent
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`Jun. 8, 1999
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`Sheet 6 of6
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`5,909,949
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`05
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`PRIOR ART
`
`FIG. 8
`
`

`
`1
`HEAD LAMP DEVICE FOR VEHICLE
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`This invention relates to light distribution control of a
`head lamp device for changing a lighting region in right and
`left directions.
`2. Discussion of Relevant Art
`Hitherto, various head lamp devices capable of changing
`a lighting region in right and left directions have been
`proposed. In almost of all of them, basically the lighting
`region of a head lamp is controlled to change in response to
`a steering angle of the steering Wheel (Japanese Laid-Open
`Patent Publications No. Sho 62-77249, No. Hei 3-14742
`etc.) and the lighting region of the head lamp is changed to
`a direction of the steering operation to increase a lighting
`amount in the direction to Which the vehicle is just going to
`advance.
`If the lighting angle is controlled in response to the
`steering angle only as above, When the steering operation is
`rapid, the lighting angle is also changed rapidly in response
`to rapid change of the steering angle so that the lighting
`region is sWung in right and left directions and largely in a
`moment to give the driver a sense of incongruity.
`When a vehicle goes around a curve, for example, if the
`steering Wheel is turned through too large an angle as
`compared With the vehicle speed, or the road surface is in a
`slippery state such as a snoWy road, sometimes the rear part
`of the vehicle projects outWardly such that it directs the
`vehicle inWard too much. FIG. 8 shoWs such a state in Which
`a vehicle 02 shoWn by the solid line is directed inWard too
`much on a midway of a road curving to the right.
`In such a case, if the steering Wheel is left in the state
`turned to the right, the vehicle 02 turns round, hoWever by
`reversing the turning direction of the steering Wheel
`(counter-steering) the direction of the vehicle body can be
`recovered. In FIG. 8, therefore the steering Wheel is turned
`to the left by counter-steering so that the front Wheels 03 are
`directed leftWard With respect to the vehicle body.
`If the lighting region of the vehicle 02 is changed in
`response to the steering angle, before the steering Wheel is
`reversed to the left direction, the region on the right side With
`respect to the front of the vehicle body is lighted as shoWn
`by the dotted line 04 in FIG. 8, and after the counter
`steering, the lighting region is directed to the left side With
`respect to the front of the vehicle body as shoWn by the solid
`line 05.
`As the counter-steering is carried out instantaneously, the
`lighting region is changed instantaneously from the region
`04 to the region 05, and the rapid and large change of the
`lighting region gives the driver a sense of incongruity.
`
`SUMMARY OF THE INVENTION
`The present invention has been accomplished in vieW of
`the foregoing and it is an object of the present invention to
`provide a head lamp device for a vehicle in Which a change
`of a lighting region is suppressed so as not to give the driver
`a sense of incongruity even if a steering Wheel is operated in
`reverse rapidly as in case of the counter-steering and the like.
`In order to accomplish the aforesaid object, the present
`invention provides a lamp device for a vehicle capable of
`changing a lighting region in front of the vehicle in right and
`left directions, comprising a head lamp lighting region
`changing means for changing the lighting region of the head
`lamp; steering angle detecting means for detecting a steering
`
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`angle; turning movement detecting means for detecting a
`turning movement of the vehicle body in right and left
`directions; ?rst lighting angle calculating means for calcu
`lating a ?rst lighting angle based on the steering angle
`detected by the steering angle detecting means; second
`lighting angle calculating means for calculating a second
`lighting angle based on the turning movement detected by
`the turning movement detecting means; lighting angle decid
`ing means for deciding a ?nal lighting angle from the ?rst
`lighting angle and the second lighting angle; and control
`means for controlling the lighting region changing means to
`change the lighting region based on the ?nal lighting angle.
`Since the ?nal lighting angle is not decided from only the
`?rst lighting angle based on the steering angle, but is decided
`in vieW of both the ?rst lighting angle and the second
`lighting angle based on the turning movement, change of the
`lighting region can be suppressed properly so as not to give
`the driver a sense of incongruity even if the steering Wheel
`is operated in one direction and then rapidly in the other.
`The lighting angle deciding means may decide the second
`lighting angle, Which is based on the turning movement, as
`the ?nal lighting angle When the ?rst and second lighting
`angles eXist on opposite sides to each other With respect to
`a direct front of the vehicle body, and may decide the larger
`of either of the ?rst and second lighting angles as the ?nal
`lighting angle When the ?rst and second lighting angles eXist
`on the same side With respect to the direct front of the
`vehicle body.
`When the vehicle goes around a curve, in the beginning
`of entering the curve, the steering angle precedes the turning
`movement and the ?rst lighting angle based on the steering
`angle is typically larger than the second lighting angle based
`on the turning movement on the same side. At that time, if
`the steering Wheel is operated in the reverse direction, the
`?rst lighting angle based on the steering angle becomes
`smaller than the second lighting angle based on the turning
`movement, because the steering angle becomes small rap
`idly While change of the turning movement is sloW due to
`inertia.
`Accordingly, When the ?rst and second lighting angles
`eXist on the same side and the ?rst lighting angle based on
`the steering angle is larger than the second lighting angle
`based on the turning movement, the lighting region is
`changed using the ?rst lighting angle as the ?nal lighting
`angle, and after the ?rst lighting angle based on the steering
`angle becomes smaller than the second lighting angle based
`on the turning movement, the lighting region is changed
`using the second lighting angle, Which changes sloWly and
`is large, as the ?nal lighting angle. Further, even if the ?rst
`lighting angle moves on the opposite side of one direct front
`of the vehicle body to the second lighting angle, the second
`lighting angle based on the turning movement is used as the
`?nal lighting angle. Thus, even if the steering Wheel is
`operated in one direction and then rapidly in the other,
`change of the lighting region can be suppressed properly to
`protect the driver from a sense of incongruity.
`The lighting angle deciding means may decide a direction
`of the direct front of the vehicle body as a ?nal lighting
`direction When the ?rst and second lighting angles eXist on
`opposite sides to each other With respect to the direct front
`of the vehicle body; may decide a lighting angle based on the
`steering angle as the ?nal lighting angle When the ?rst and
`second lighting angles eXist on the same side With respect to
`the direct front of the vehicle body and the ?rst lighting
`angle is larger than the second lighting angle; and may
`decide the direction of the direct front of the vehicle body as
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`a ?nal lighting direction When the ?rst and second lighting
`angles exist on the same side With respect to the direct front
`of the vehicle body and the ?rst lighting angle is smaller than
`the second lighting angle.
`When the ?rst lighting angle based on the steering angle
`is larger than the second lighting angle based on the turning
`movement, change of the lighting region is controlled using
`the ?rst lighting angle based on the steering angle as the ?nal
`lighting angle, and When the ?rst lighting angle based on the
`steering angle becomes smaller than the second lighting
`angle based on the turning movement, the direction of the
`direct front of the vehicle body is decided as the ?nal
`lighting direction, and even if the ?rst and second lighting
`angles come to eXist on opposite sides of the direct front to
`each other, the direction of the direct front of the vehicle
`body is decided as the ?nal lighting direction and the
`lighting region is controlled to the direct front of the vehicle
`body. Thus, When the steering Wheel is operated in one
`direction and then rapidly in the other, the lighting region is
`set at the direct front of the vehicle body so that change of
`the lighting region can be suppressed properly so as not to
`give the driver a sense of incongruity.
`In an aspect of the present invention, When the ?rst and
`second lighting angle eXist on the same side With respect to
`a direct front of the vehicle body, if the ?rst lighting angle
`is larger than the second lighting angle, a lighting angle
`based on the steering angle is decided as the ?nal lighting
`angle, and if the ?rst lighting angle is changed to be smaller
`than the second lighting angle, a lighting angle at the time
`of changing is decided as the ?nal lighting angle and ?Xed.
`After that if the ?rst and second lighting angles change so as
`to eXist on opposite sides to each other With respect to the
`direct front of the vehicle body, a lighting angle at the time
`of change is decided as the ?nal lighting angle and ?Xed.
`When the ?rst lighting angle based on the steering angle
`is larger than the second lighting angle based on the turning
`movement, the ?rst lighting angle based on the steering
`angle is decided as the ?nal lighting angle and the lighting
`angle is ?Xed. When the ?rst lighting angle based on the
`steering angle becomes smaller than the second lighting
`angle based on the turning movement, the lighting angle at
`that time is ?Xed as the ?nal lighting angle and even if the
`?rst and second lighting angles come to eXist on opposite
`sides to each other relative to the direct front of the vehicle
`body, and the lighting angle is kept ?Xed. Thus, When the
`steering Wheel is operated rapidly, the lighting region is
`?Xed so as not to give the driver a sense of incongruity.
`If vehicle speed detecting means for detecting vehicle
`speed is provided, and the turning movement detecting
`means detects a yaW angular velocity of yaWing of the
`vehicle body, and the second lighting angle calculating
`means further calculates the second lighting angle on the
`basis of the yaW angular velocity and the vehicle speed
`detected by the vehicle speed detecting means, an eXact
`second lighting angle based on the yaWing of the vehicle
`body can be calculated.
`The second lighting angle calculating means may calcu
`late a turning radius of the vehicle from the yaW angular
`velocity and the vehicle speed to obtain the second lighting
`angle in accordance With the turning radius. A second
`lighting angle adapted to a curve of a road can correspond
`ingly be calculated.
`If vehicle speed detecting means for detecting vehicle
`speed is provided, and the ?rst lighting angle calculating
`means corrects the steering angle detected by the steering
`angle detecting means in accordance With the vehicle speed
`
`4
`detected by the vehicle speed detecting means to obtain the
`?rst lighting angle, it is possible to make the ?rst lighting
`angle based on the steering angle an eXact angle according
`to the vehicle speed.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a vieW shoWing lighting regions of a vehicle of
`one embodiment of the present invention as vieWed from
`above;
`FIG. 2 is a schematic perspective vieW shoWing a sWing
`ing mechanism for a head light of the preferred embodiment;
`FIG. 3 is a rough block diagram shoWing a control system
`for changing the lighting region;
`FIG. 4 is an illustration for introducing a formula for
`calculating turning radius R;
`FIG. 5 is an illustration for introducing a formula for
`calculating a second lighting angle 62;
`FIG. 6 is a How chart shoWing a procedure for controlling
`change of the lighting region;
`FIGS. 7A to 7D are graphs shoWing changes of steering
`angle 4), yaW angular velocity u), ?rst and second lighting
`angles 61, 62 and ?nal lighting angle 6 respectively; and
`FIG. 8 is an illustration for shoWing change of the lighting
`region on counter-steering in a prior art.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`
`Hereinafter, a preferred embodiment of the present inven
`tion Will be described With reference to FIGS. 1 to 7.
`The vehicle 1 of the preferred embodiment has head lights
`2 for lighting the space in front of the vehicle installed such
`that they are sWingable in rightWard and leftWard horiZontal
`directions. FIG. 1 is a vieW shoWing the vehicle 1 from
`above and in this ?gure, the right and left head lights 2, 2 are
`sWung rightWard so as to cause the right forWard regions to
`become lighting regions 3, 3.
`The right and left head lights 2, 2 are sWung together in
`the same direction by the same angle and as shoWn in FIG.
`1, angles of their optical aXes L, L With respect to an
`advancing direction of the vehicle, i.e. lighting angle, are
`both set to be 6. Regarding the angle 6, that on the right side
`With respect to the advancing direction is given plus sign and
`that on the left is given minus sign.
`Alternatively, only a head light on the turning side may be
`sWung or the right and left head lights may be sWung by
`respective angles different from each other.
`A sWinging mechanism for sWinging the head light 2 in
`the preferred embodiment is schematically shoWn in FIG. 2,
`Wherein a lamp unit 4 of the head light 2 is ?Xed to a rotary
`shaft 5, and a Worm gear 7 formed at an end of a driving
`shaft of a motor 8 is engaged With a Worm Wheel 6 ?tted to
`the rotary shaft 5.
`Accordingly, the lamp unit 4 is sWung together With the
`rotary shaft 5 through an engagement betWeen the Worm
`gear 7 and the Worm Wheel 6 under a driving of the motor
`8. The motor 8 is controlled for its driving by a light
`distribution control ECU 10.
`FIG. 3 is a rough block diagram shoWing a control system
`for changing the lighting region in the present embodiment.
`The vehicle has a steering angle sensor 21 for detecting a
`direction of a front Wheel With respect to the vehicle body,
`ie a steering angle (1), a vehicle speed sensor 22 for detecting
`a vehicle speed v and a yaW rate sensor 23 for detecting a
`yaW angular velocity (yaW rate) 00.
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`The steering angle 4) detected by the steering angle sensor
`21 and the vehicle speed v detected by the vehicle speed
`sensor 22 are inputted into a ?rst lighting angle calculating
`means 11 in the light distribution control ECU 10, and a ?rst
`lighting angle 61 is calculated by the folloWing formula
`
`Wherein K(v) is a correction coef?cient determined based
`on the vehicle speed v and about proportional to the vehicle
`speed v. The maximum value of the K(v) is 1.
`In such a manner, the ?rst lighting angle calculating
`means 11 calculates the ?rst lighting angle 61 based on the
`steering angle 4) and corrected in accordance With the vehicle
`speed v so that an appropriate ?rst lighting angle 61 corre
`sponding to the vehicle speed v can be obtained.
`The vehicle speed v detected by the vehicle speed sensor
`22 and the yaW angular velocity detected by the yaW rate
`sensor 23 are inputted into a second lighting angle calcu
`lating means 12 in the light distribution control ECU 10 to
`calculate a second lighting angle 62.
`In the second lighting angle calculating means 12, ?rstly
`a turning radius of the vehicle is obtained from the vehicle
`speed v and the yaW angular velocity 00.
`Referring to FIG. 4, When the vehicle 1 goes around a
`rightWard curve at a vehicle speed v, the yaW angular
`velocity u) of the vehicle body corresponds to angular
`velocity of turning of the vehicle 1, and therefore the turning
`radius R can be calculated by the folloWing formula
`
`Referring to FIG. 5, a curved road shoulder 30 on the right
`side of a right curve road is assumed to be an ideal circular
`arc and a distance from the vehicle 1 to the road shoulder 30
`is assumed to be X.
`The second lighting angle 62 is calculated on the assump
`tion that a direction of a tangent draWn from the vehicle 1 to
`the circular-arc-shaped road shoulder 30 is the fundamental
`lighting direction of the head lamp.
`If the turning center is denoted by C, the position of the
`vehicle 1 by M and a contact point of the tangent and the
`road shoulder 30 by N, the second lighting angle 62 is equal
`to an angle of a right-angled triangle MNC at the apeX C.
`Therefore the neXt formula is established.
`
`The second lighting angle calculating means 12 calculates
`the second lighting angle 62 by the formula
`From the ?rst lighting angle 61 based on the steering angle
`4) and the second lighting angle 62 based on the yaW angular
`velocity u) is decided a ?nal lighting angle 6 by a lighting
`angle deciding means 13.
`The ?nal lighting angle 6 is decided from Whether the ?rst
`lighting angle 61 and the second lighting angle 62 eXist on
`the same side With respect to the advancing direction of the
`vehicle or not, that is, the angles 61, 62 have the same sign
`or not, and comparison of absolute values |61| and |62| of the
`lighting angles 61, 62.
`A control signal according to the ?nal lighting angle 6
`obtained in such a manner is outputted to a motor driver 24
`Which drives the right and left motors 8 for sWinging the
`head lights 2 to a direction corresponding to the lighting
`angle 6.
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`The above-mentioned procedures are shoWn in the How
`chart of FIG. 6, inclusively.
`At ?rst, the vehicle speed v, the steering angle 4) and the
`yaW angular velocity u) detected by respective sensors are
`read (Step 1). Then, the ?rst lighting angle 61 is calculated
`from the steering angle 4) and the vehicle speed v by the
`formula (1) (Step 2), the turning radius R is calculated from
`the yaW angular velocity u) and the vehicle speed v by the
`formula (2) (Step 3), and the second lighting angle 62 is
`calculated from the turning radius R by the formula (3) (Step
`4).
`Next, Whether a sign of the product 61x62 of the ?rst
`lighting angle 61 and the second lighting angle 62 is positive
`or not is discriminated (Step 5).
`If the sign is positive, it is judged that the both lighting
`angles 61 and 62 are of the same sign and eXist on the same
`right or left side With respect to the advancing direction of
`the vehicle, and the How advances to Step 6. If the sign is
`negative, it is judged that the ?rst and second lighting angles
`61, 62 eXist on opposite sides to each other With respect to
`the advancing direction of the vehicle, and the How advances
`to Step 8.
`At the Step 8, the second lighting angle 62 based on the
`yaW angular velocity is decided as the ?nal lighting angle 6
`alWays.
`At the Step 6 Where 61 and 62 are of the same sign and
`eXist on the same side, |61| is compared With |62|, and if
`|61|>|62|, the How advances to Step 7 and the ?rst lighting
`angle 61 is decided as the ?nal lighting angle 6. If |61|§|62|
`at the Step 6, the How advances to Step 8 and the second
`lighting angle 62 is again decided as the ?nal lighting angle
`6
`
`At the Step 9, the light distribution control is carried out
`on the basis of the ?nal lighting angle 6 decided at the Step
`7 or 8.
`Change of the lighting angle 6 according to the above
`mentioned light distribution control Will be considered With
`regard to an eXample shoWn in FIGS. 7A to 7D.
`FIG. 7A and FIG. 7B shoW changes of the steering angle
`4) and the yaW angular velocity 00 respectively, and in these
`?gures the time aXes (horiZontal aXes) coincide With each
`other.
`Referring to FIG. 8, from changes of the steering angle 4)
`and the yaW angular velocity u) of FIGS. 7A and 7B, the
`folloWing is understood. When the vehicle goes around the
`rightWard curve, the steering Wheel is turned to the right to
`have a positive steering angle 4) at ?rst, and the vehicle body
`yaWs someWhat after the change of steering angle 4) so that
`the yaW angular velocity 00 increases folloWing increase of
`the steering angle.
`In the meantime, the rear part of the vehicle is sWung
`outside large, and therefore the driver turns the steering
`Wheel to the left or in the opposite direction rapidly for
`counter-steering to recover direction of the vehicle. Namely,
`the steering angle 4) changes from an upWard incline to a
`doWnWard incline in FIG. 7A. HoWever, the yaW angular
`velocity u) is maintained due to inertia.
`Further, When the direction of the vehicle comes to shoW
`some recovery, the driver again turns the steering Wheel to
`the right for going around the rightWard curve, but he comes
`to carry out the counter-steering again soon after. Thus, the
`steering angle 4) sWings rightWard and leftWard in large
`variations.
`HoWever, While the steering angle 4) is sWinging rightWard
`and leftWard as described above, the yaW angular velocity u)
`is maintained at a certain angular velocity stably in general,
`and at a time someWhat before the vehicle passes through the
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`curve completely, the yaW angular velocity 00 comes to
`coincide With the steering angle 4).
`When the vehicle runs in the manner as mentioned above,
`the ?rst lighting 61 and the second lighting angle 62 change
`as shoWn in FIG. 7C.
`The ?rst lighting 61 based on the steering angle 4) is
`corrected by the vehicle speed v, but on the assumption that
`the vehicle speed v does not change so much, the ?rst
`lighting angle 61 changes in the same Way as the steering
`angle 4) as shoWn by the dotted line in FIG. 7C.
`The second lighting angle 62 based on the yaW angular
`velocity u) is also in?uenced by the vehicle speed v, but on
`the assumption that the vehicle speed v is about constant, the
`second lighting angle 62 changes in the same manner as the
`yaW angular velocity 00 (FIG. 7B) as seen from the formulas
`(2) and
`This second lighting angle 62 is shoWn by the
`dot-dash line in FIG. 7C.
`The ?nal lighting angle 6 decided by selecting the ?rst
`lighting angle 61 or the second lighting angle 62 through the
`discrimination of Steps 5 and 6 in the How chart of FIG. 6
`is shoWn in FIG. 7D by the solid line.
`In a portion of the solid line in FIG. 7D When the vehicle
`begins to go around the right curve, a condition of (61>62>0)
`eXists so that the How passes through the route of Steps 5,6
`and 7 and the ?rst lighting angle 61 is selected as the ?nal
`lighting angle 6. When the counter-steering is carried out
`and the relation of the ?rst lighting 61 and the second
`lighting angle 62 are reversed to (0<61<62), the How passes
`through the route of Steps 5, 6 and 8 and the second lighting
`angle 61 is selected as the ?nal lighting angle 6.
`Thereafter, even if 61 becomes negative While 62 remains
`to be positive, the How passes through the Steps 5 and 8 and
`the second lighting angle 62 is selected as the ?nal lighting
`angle 6.
`Since the actual light distribution control is performed on
`the basis of the above-mentioned ?nal lighting angle 6, even
`if the steering Wheel is operated rapidly for the counter
`steering and the like, change of the lighting region is
`suppressed pertinently and the driver is given no sense of
`incongruity.
`It is to be noted that if the light distribution control is
`carried out only in accordance With the ?rst lighting angle 61
`based on the steering angle 4), the light distribution sWings
`rightWard and leftWard in large variations in a short time as
`shoWn by the dotted line in FIG. 7C so that it gives not only
`the driver a sense of incongruity, but surrounding vehicle
`some troubles as Well.
`In the above embodiment, in a situation Where 61x62<0
`and a situation Where 61x62>0 and |61|<|62|, the second
`lighting angle 62 is selected as the ?nal lighting 6, but in
`those situations, the ?nal lighting angle 6 may be ?Xed at 0
`(rad), namely the direction of the lighting may alternatively
`be ?Xed to the direct front of the vehicle body.
`Since the lighting region is returned to the direct front of
`the vehicle body and ?Xed to prevent rightWard and leftWard
`sWinging of light distribution When the steering Wheel is
`operated rapidly, the driver is given no sense of incongruity
`and the direction of the vehicle body can be recogniZed
`easily.
`Further, the ?nal lighting angle 6 may be ?Xed to the then
`lighting angle at the time When |61| and |62| are reversed in
`siZe, i.e., at the time When the ?rst and second lighting
`angles are changed such that one of the angles Which just
`previously had the larger absolute value noW has the smaller
`absolute value. Even if the steering Wheel is operated
`rapidly, rightWard and leftWard sWinging of the light distri
`bution is prevented so as not to give the driver a sense of
`incongruity.
`
`15
`
`25
`
`35
`
`45
`
`55
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`65
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`8
`Although there has been described What is at present
`considered to be the preferred embodiment of the invention,
`it Will be understood by persons skilled in the art that
`variations and modi?cations may be made thereto Without
`departing from the spirit or essence of the invention. The
`scope of the invention is, therefore, indicated by the
`appended claims, rather than by the foregoing description.
`What is claimed is:
`1. A head lamp device for a vehicle capable of changing
`a lighting region in front of the vehicle in right and left
`directions, comprising:
`a head lamp;
`lighting region changing means for changing a lighting
`region of the head lamp;
`steering angle detecting means for detecting a steering
`angle;
`turning movement detecting means for detecting a turning
`movement of a body of the vehicle in right and left
`directions;
`?rst lighting angle calculating means for calculating a ?rst
`lighting angle based on said steering angle detected by
`said steering angle detecting means;
`second lighting angle calculating means for calculating a
`second lighting angle based on said turning movement
`detected by said turning movement detecting means;
`lighting angle deciding means for deciding a ?nal lighting
`angle from said ?rst lighting angle and said second
`lighting angle; and
`control means for controlling said lighting region chang
`ing means to change said lighting region based on said
`?nal lighting angle.
`2. A head light lamp device for a vehicle as claimed in
`claim 1, Wherein said lighting angle deciding means decides
`said second lighting angle based on the turning movement as
`said ?nal lighting angle When said ?rst and second lighting
`angles eXist on opposite sides to each other With respect to
`a direct front of the vehicle body, and decides either of said
`?rst and second lighting angles Which is larger as said ?nal
`lighting angle When said ?rst and second lighting angles
`eXist on the same side With respect to the direct front of the
`vehicle body.
`3. A head lamp device for a vehicle as claimed in claim
`2, further including vehicle speed detecting means for
`detecting vehicle speed, said turning movement detecting
`means detects a yaW angular velocity of yaWing of the
`vehicle body, and said second lighting angle calculating
`means calculates said second lighting angle based on said
`yaW angular velocity and said vehicle speed detected by said
`vehicle speed detecting means.
`4. A head lamp device for a vehicle as claimed in claim
`2, Wherein said second lighting angle calculating means
`calculates a turning radius of the vehicle from said yaW
`angular velocity and said vehicle speed to obtain said second
`lighting angle in accordance With said turning radius.
`5. A head lamp device for a vehicle as claimed in claim
`2, Wherein said ?rst lighting angle calculating means cor
`rects said steering angle detected by said steering angle
`detecting means in accordance With said vehicle speed
`detected by said vehicle speed detecting means to obtain
`said ?rst lighting angle.
`6. A head lamp device for a vehicle as claimed in claim
`1, Wherein said lighting angle deciding means decides a
`direction of a direct front of the vehicle body as a ?nal
`lighting direction When said ?rst and second lighting angles
`eXist on opposite sides to each other With respect to the
`direct front of the vehicle body, decides said ?rst lighting
`
`

`
`9
`angle based on said steering angle as said ?nal lighting angle
`When said ?rst and second lighting angles eXist on the same
`side With respect to the direct front of the vehicle body and
`said ?rst lighting angle is larger than said second lighting
`angle, and decides the direction of the direct front of the
`vehicle body as the ?nal lighting region When said ?rst and
`second lighting angles eXist on the same side With respect to
`the direct front of the vehicle body and said ?rst lighting
`angle is smaller than said second lighting angle.
`7. A head lamp device for a vehicle as claimed in claim
`6, further including vehicle speed detecting means for
`detecting vehicle speed, said turning movement detecting
`means