United States Patent
`
`[19]
`
`Ikegami et al.
`
`[54]
`
`[75]
`
`HEADLAMP
`
`Inventors: Masahiko Ikegami, Kumamoto;
`Kaoru Hatanaka, Niiza; Tsuneo
`Sekiguchi, Tokyo; Hideyuki Tanabe,
`Yokohama; Satoru Suzuki, Iohjkawa,
`all of Japan
`
`[73] Assignee:
`
`Honda Giken Kogyo Kabushiki
`Kaisha, Tokyo, Japan
`
`[21]
`
`Appl. No.: 647,439
`
`[22] Filed:
`
`Jan. 29, 1991
`
`Foreign Application Priority Data
`[30]
`Jan. 31, 1990 [JP]
`Japan .................................... 2-21073
`Feb. 15, 1990 [JP]
`Japan .................................... 2-32596
`
`B60Q 1/02; B60Q 1/10
`Int. Cl.5
`[51]
`[52] U.S. C1. ...................................... .. 362/71; 362/61;
`362/72; 362/284; 362/319
`[58] Field of Search ..................... .. 362/61, 66, 71, 72,
`362/80, 284, 324, 322, 277, 319, 351, 282
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`2,015,935 10/1935 Herring ............................. .. 362/284
`3,598,989
`8/1971 Biggs . . . . . . . .
`. . . . .. 362/61
`4.875,141 10/1989 Miyauchfet a1.
`.... .. 362/61
`4.922,390
`5/1990 Nakazawa et al.
`.. 362/72
`4,985,816
`1/1991 Seko et al.
`.......................... .. 362/61
`
`FOREIGN PATENT DOCUMENTS
`
`||||||||||||||Ill||||||||||||||||||||||l||llllllllllIllllllllllllllllllllll
`US005 1 5233 52A
`
`I11]
`
`[45]
`
`Patent Number:
`
`Date of Patent:
`
`5,158,352
`
`Oct. 27, 1992
`
`294598 12/1988 Fed. Rep. of Germany ...... .. 362/80
`63158701
`7/1988 Japan .
`6441484
`2/1989 Japan .
`1244934 9/1989 Japan 1
`
`Primary Examiner-Ira S. Lazarus
`Assistant Examiner—Y. Quach
`Attorney, Agent, or Firm—Irving M. Weiner; Joseph P.
`Carrier; Pamela S. Burt
`
`[57]
`
`ABSTRACT
`
`A headlamp provided with correcting means for cor-
`recting a light distribution characteristic which is
`caused by an inclination of a vehicle body with respect
`to a road surface. An outer lens section fixed to the
`vehicle body is provided forwardly of a lamp body
`section of the projector type which is pivoted around an
`optical axis so as to maintain the light distribution char-
`acteristic horizontal in response to the inclination of the
`vehicle body, and the outer lens section has a lens cut
`formed thereon for diffusing a variation component of
`passing light to a turning direction when the car body is
`inclined for turning. Alternatively a light stopping plate
`for stopping a part of light advancing from a reflecting
`mirror toward a convex lens is provided at a position of
`a focus of the convex lens on the reflecting mirror side
`for tilting around an optical axis, and a bearing for tilt-
`ably supporting the light stopping plate is provided on
`the optical axis in a displaced relationship to the reflect-
`ing mirror side with respect to the "light stopping plate.
`
`3241713
`
`5/1984 Fed. Rep. of Germany ...... .. 362/66
`
`5 Claims, 6 Drawing Sheets
`
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`Koito Manufacturing v. Adaptive Headlam
`|PR2016-0007
`
`KOITO 103
`
`1
`
`KOITO 1034
`Koito Manufacturing v. Adaptive Headlamp
`IPR2016-00079
`
`

`
`U.S. Patent
`
`Oct. 27, 1992
`
`Sheet 1 of 6
`
`5,158,352
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`U.S. Patent
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`Oct. 27, 1992
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`Sheet 2 of 6
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`3
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`U.S. Patent
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`Oct. 27, 1992
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`Sheet 3 of 6
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`Oct. 27, 1992
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`U.S. Patent
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`Oct. 27, 1992
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`Sheet 5 of 6
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`5,158,352
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`
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`FIG. 10
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`PRIOR ART
`
`6
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`

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`U.S. Patent
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`Oct. 27, 1992
`
`Sheet 6 of 6
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`5,158,352
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`12
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`
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`FIG. 13a
`PRIOR ART
`
`FIG. 13b
`PRIOR ART
`
`7
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`1
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`HEADLAMP
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`5,158,352
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`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present
`invention relates to a headlamp, and
`more particularly to a so called cornering headlamp
`which is formed so as to correct a light distribution
`characteristic which is caused by an inclination of a
`motorcycle or the like wherein a vehicle body is liable
`to be inclined with respect to a road surface.
`2. Discussion of Relevant Art
`FIG. 10 shows an example of such a conventional
`cornering headlamp 030 of the type mentioned as is
`disclosed in the Official Gazette of Japanese Patent
`Laid-Open No. 41484/1989, and an inclination sensor
`021 which makes use of a gyroscope or ultrasonic
`waves is provided on a vehicle body 020 while a head-
`lamp body 031 is constructed for pivotal movement
`around an optical axis relative to the vehicle body 020.
`When an inclination is detected by the inclination sen-
`sor 021, the headlamp body 031 is pivoted with respect
`to a road surface 022 in response to an output of the
`inclination sensor 021. The headlamp body 031 is piv-
`oted by a driving device 023 which makes use of a
`motor or the like so that the degree of such pivotal
`movement may be such that the light distribution char-
`acteristic may be parallel to the road 22, that is, the light
`distribution characteristic may be the same as that when
`the vehicle body stands upright.
`However, with a motorcycle, since the irradiation
`distance in an advancing direction upon cornering be-
`comes shorter than that upon straightforward advance-
`ment, if the light distribution characteristic is only cor-
`rected to a horizontal direction, there is the possibility
`that the resulting effect cannot be exhibited sufficiently
`even though such complicated construction as de-
`scribed above is employed.
`On the other hand, a headlamp is known which is
`constituted such that a predetermined light distribution
`pattern may be formed by stopping a part of the light
`radiating from a light source by means of a light stop-
`ping plate disposed on a front opening side of a reflect-
`ing mirror. A headlamp of the type mentioned is dis-
`closed in the Official Gazette of Japanese Patent Laid-
`Open No. 158701/1988 wherein the light stopping plate
`is tilted leftwardly or rightwardly in response to an
`inclination of the vehicle body to change the light distri-
`bution pattern so as to normally present a good light
`distribution to required portions forwardly of the vehi-
`cle body.
`No.
`Gazette
`Official
`aforementioned
`The
`158701/1988 discloses a headlamp 0] as shown in FIG.
`11. This headlamp is constituted such that a light source
`03 is disposed at a first focus F1 of a reflecting mirror 02
`having a reflecting face of an ellipsoid of revolution,
`and light reflected from the reflecting mirror 02 is fo-
`cused upon a second focus F2 and then introduced into
`a convex lens 04, whereafter it is projected forwardly
`from the convex lens 04, and a stopping plate 05 is
`provided between the reflecting mirror 02 and the con-
`vex lens 04. The center of an upper edge of the stopping
`plate 05 is positioned on an optical axis X—X, while a
`left upper edge portion 05a extends horizontally at a
`same height as the optical axis, and a right upper edge
`portion 05b is inclined downwardly. Since light to be
`introduced into a lower half portion of the convex lens
`04 from an upper half portion of the reflecting mirror 02
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`is stopped by the stopping plate 05, if light from the
`convex lens 04 is projected on a projection plane 06
`positioned sufficiently forwardly, then a light distribu-
`tion pattern wherein a lower portion is a bright portion
`07 and an upper portion is a dark portion 08 is obtained.
`A right horizontal bright/dark boundary line 09a corre-
`sponds to a real image of the left upper edge 05a of the
`stopping plate 05, while a left, leftwardly upwardly
`inclined bright/dark boundary line 09b corresponds to a
`real image of the upper edge 05b. Since a focus F3 of the
`convex lens 04 is at a position a little forwardly of the
`stopping plate 05, however the degree of an out-of-
`focus condition of the image is low, and accordingly,
`the bright/dark boundary lines 09a and 0917 obtained are
`clear lines.
`While such a light distribution pattern is obtained
`when the vehicle body stands uprightly, if the headlamp
`01 is inclined, for example, to the left-hand side together
`with the vehicle body, then the bright/dark boundary
`line 09b is tilted downwardly while the bright/dark
`boundary line 09a is tilted upwardly. Accordingly, in
`such instance, the stopping plate 05 is inclined to the
`right-hand side around the central point of the upper
`edge on the optical axis X—X to maintain the light
`distribution pattern shown in the figure.
`To this end, the stopping plate 05 is supported for
`tilting motion as shown in FIG. 12. In particular, arcu-
`ate guided ribs 010, 010 centered at the central point 0
`of the aforementioned upper edge are individually
`formed on the opposite faces of an intermediate portion
`of the stopping plate 05 in upward and downward di-
`rections while also a lower edge is formed in an arcuate
`shape centered at the aforementioned central point 0
`and a gear 011 is formed on the lower edge. The stop-
`ping plate 05 is inserted into a slit 013 of an arcuate
`frame member 012 from above, and the guided ribs 010
`are fitted for sliding movement in guide grooves formed
`in the opposite side walls of the slit 013 and having a
`same curvature as the guided ribs 010. The gear 011
`projected downwardly from the frame member 012 is
`held in meshing engagement with a gear of a motor
`shaft (not shown), and when the motor is rotated, the
`guided ribs 010 are slidably moved along the guide
`grooves so that the stopping plate 05 is tilted leftwardly
`or rightwardly around the central point 0, that is, the
`optical axis.
`Since the headlamp disclosed in the aforementioned
`Official Gazette includes such stopping plate supporting
`and tilting device, the structure is complicated, and it
`cannot be avoided for the headlamp to be great in size.
`By the way, a simplest method of supporting the
`stopping plate 05 for tilting motion aroundtthe central
`point 0 is to support the stopping plate 05 at the central
`point 0 by means of a bearing, but where such construc-
`tion is employed, an upper half portion of the bearing
`will be projected upwardly above the central point O.
`However, since the bearing section is located very
`proximately to the position of a focus of the convex lens
`04, a clear real image enlarged by the convex lens 04 is
`produced on the projection plane at a forward position,
`and the light distribution on a screen placed at a position
`spaced, for example, forwardly by 10 m is such as
`shown in FIG. 13a while the light distribution condition
`on a real road is such as shown in FIG. 131:. In those
`
`drawings, reference character 08a denotes a shadow
`(dark portion) produced by an image of the bearing
`section, and R denotes a road, R; a road shoulder, and
`
`8
`
`

`
`3
`H a horizontal line. Needless to say, such light distribu-
`tion is not preferable.
`SUMMARY OF THE INVENTION
`
`The present invention makes it possible to extend
`irradiation upon the exterior in a turning direction to a
`remote position to solve the conventional subject above
`by providing, as particular means for solving the subject
`described above, a cornering headlamp provided with
`correcting means for correcting a light distribution
`characteristic which is caused by an inclination of a
`vehicle body with respect to a road surface. The comer-
`ing headlamp is characterized in that the correcting
`means includesa lamp body section of the projector
`type which is pivoted around an optical axis so as to
`maintain a horizontal condition of the light distribution
`characteristic in response to an output of inclination
`detecting means for detecting an inclination of the vehi-
`cle body, and an outer lens section provided in a fixed
`relationship on the vehicle body forwardly of the lamp
`body section and having a lens cut formed thereon for
`diffusing a variation component of passing light by
`pivotal motion of the lamp body section to a turning
`direction when the vehicle body is inclined.
`Also, the present invention contemplates attainment
`of simplification and miniaturization of a stopping plate
`supporting mechanism, as well as prevention of appear-
`ance of a dark portion in a light distribution pattern
`arising from a bearing section by supporting such a
`stopping plate (light stopping plate) as described above
`by means of a bearing on an optical axis passing the
`central point of an upper edge of the stopping plate.
`To this end, according to the invention,
`in a light
`distribution changing device for a headlamp wherein
`light from a light source is reflected by a reflecting
`mirror and then projected forwardly by way of a con-
`vex lens, the light distribution changing device being
`constituted such that a light stopping plate for stopping
`a part of light advancing from the reflecting mirror
`toward the convex lens is provided substantially at a
`position of a focus of the convex lens on the reflecting
`mirror side and the light distribution is changed by
`tilting the light stopping plate around an optical axis. A
`bearing for supporting the light stopping plate for tilting
`motion thereon is provided on the optical axis in a dis-
`placed relationship to the reflecting mirror side with
`respect to the light stopping plate.
`According to the invention, since the light stopping
`plate is supported by means of the bearing on the optical
`axis which is an axial line of tilting motion of the light
`stopping plate, the supporting structure for the light
`stopping plate is simplified and miniaturized remark-
`ably. Accordingly, the entire headlamp is reduced in
`size and cost. Besides, since the bearing is provided at a
`position displaced from the light stopping plate to the
`reflecting mirror side, that is, at a position spaced suffi-
`ciently from the focus of the convex lens to the reflect-
`ing mirror side, an image of the bearing projected by the
`convex lens is put into an out-of-focus condition at a
`remote place and will not have any influence upon a
`light distribution pattern.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
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`FIG. 1 is a sectional view showing an embodiment of
`a cornering headlamp according to the present inven-
`tion;
`FIG. 2 is a front elevational view showing an essen-
`tial part of the same embodiment;
`
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`FIGS. 3 and 4 are explanatory views individually
`illustrating operation of the embodiment;
`FIG. Sis a longitudinal sectional view of a lamp main
`body showing another embodiment of the present in-
`vention;
`FIG. 6 is a perspective view of a light stopping plate
`supporting portion of the embodiment;
`FIG. 7 is a fragmentary perspective view of the same;
`FIGS. 80 and 8b are drawings for explaining a light
`distribution obtained by the embodiment;
`FIG. 9 is a longitudinal sectional view of a headlamp
`showing other embodiment of the present invention;
`FIG. 10 is an explanatory view showing a conven-
`tional example;
`FIG. 11 is a drawing conceptively showing a conven-
`tional headlamp;
`FIG. 12 is a fragmentary perspective view showing a
`stopping plate supporting structure of the headlamp of
`FIG. 11; and
`FIGS. 13a and 1311 are drawings for explaining a light
`distribution of a certain headlamp which is not based on
`the present invention.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`Subsequently, the present invention will be described
`in detail with reference to the embodiments shown in
`the figures.
`Reference numeral 31 in FIG. 1 denotes a cornering
`headlamp, and the cornering headlamp 31 is constituted
`roughly from a lamp body section 32 and an outer lens
`section 33. The lamp body section 32 is of the projector
`type which includes an elliptical reflecting face 32b
`having disposed at one of a pair of focuses thereof a bulb
`32a which serves as a light source, a projecting lens 32c
`disposed in the proximity of the other focus of the ellip-
`tical reflecting face 32b and having an optical axis Z
`common to the elliptical reflecting face 32b, and a light
`stopping plate 32d disposed in the proximity of a focus
`of the projecting lens 32c for determining a light distri-
`bution characteristic. The lamp body section 32 is piv-
`oted around the optical axis Z in response to an output
`corresponding to a degree of inclination from an incli-
`nation sensor (not shown) which is provided on the
`vehicle body 40 and described hereinabove in connec-
`tion with the conventional example so that the distribu-
`tion characteristic H thereof may normally be kept in
`the same condition as that when the vehicle body 40
`stands uprightly.
`On the other hand, the outer lens section 33 is dis-
`posed in a fixed relationship on the vehicle body 40 side,
`and accordingly, when the vehicle body is inclined, the
`outer lens 33 is inclined at the same time.
`Here, in order to simplify description and facilitate
`understanding of the present invention, the lamp body
`section 32 will be hereinafter described as having a
`distribution characteristic H (refer to FIG. 2) of a sub-
`stantially sectoral shape of a lower half obtained by
`cutting a circle along a horizontal line passing the cen-
`ter line.
`Since the construction is employed which includes
`the pivotal lamp body section 32 and the fixed outer lens
`section 33 described above, first when the vehicle body
`40 is in an upright standing condition, while straightfor-
`wardly advancing or the like, light from the lamp body
`section 32 passes only through a lens lower half portion
`330 of the outer lens section 33 as shown in FIG. 2, and
`since the lens lower half portion 33a is not optically
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`processed such as by lens cutting and accordingly is
`transparent,
`the light distribution characteristic H of
`light from the lamp body section 32 is not changed in
`shape at all by the outer lens section 33 and remains in
`its original shape, in which light is irradiated forwardly.
`Subsequently, when the vehicle body 40 is inclined
`rightwardly, for example, in order to turn rightwardly,
`the lamp body section 32 is pivoted so that the light
`distribution characteristic H is maintained horizontally,
`but since the outer lens section 33 is fixed to the vehicle
`body 40, it is inclined rightwardly together with the
`vehicle body 40.
`Such condition is shown in FIG. 3, and a part of the
`light distribution characteristic H portion of light from
`the light body section 32 provides a varying portion in
`light passing position such that
`it passes through an
`upper right portion of the outer lens section 33, and at a
`suitable portion of a rightward inclination variation
`portion 33b of the outer lens section 33 which appears
`upon rightward inclination, a rightward diffusion cut
`33c is formed, for example, by prism cutting for diffus-
`ing the light distribution characteristic H passing
`through the portion further to the right-hand side.
`Since the rightward diffusion cut 33c is provided at
`the rightward inclination variation portion 33b of the
`outer lens section 33 as described above, the light distri-
`bution characteristic Hr when the vehicle body 40 is
`inclined rightwardly is diffused rightwardly and the
`cornering headlamp 31 also illuminates a rightwardly
`curved road surface 41, that is, in an advancing direc-
`tion as shown in FIG. 4.
`It is to be noted that reference character 33d in FIG.
`2 denotes a leftward inclination variation portion, and a
`leftward diffusion cut 33e is provided also at the left-
`ward inclination variation portion 3341 so that, when the
`vehicle body 40 is inclined leftwardly, it acts in a similar
`manner as in the case when the vehicle body 40 is in-
`clined rightwardly.
`Here, describing an action and an effect according to
`the present embodiment, with the headlamp of'the pro-
`jector type employed as the lamp body section 32, due
`to its principle that a shape of the light stopping plate
`32d is projected by way of the projecting lens 32c, the
`correlation in shape between a light distribution charac-
`teristic H at a position directly forwardly of the project-
`ing lens 326, that is, a position at which the outer lens 33
`is provided, and that at a position on the road surface 41
`to which the light is projected finally is high, and diffu-
`sion caused by the outer lens 33, for example, by an
`upper right half portion of the outer lens 33, appears
`similarly at an upper right half portion of a light distri-
`bution characteristic H when light is projected to the
`road surface 41. Thus, a light distribution characteristic
`H which coincides at a very high level with that antici-
`pated by a designer can be obtained with the outer lens
`33.
`the headlamp of the projector type de-
`Further,
`scribed above is generally small in size, particularly in a
`diametrical direction around the optical axis Z com-
`pared to a headlamp which employs a paraboloid of
`revolution, and a driving section for rotating the light
`body section 32 can be simplified.
`FIG. 5 is a longitudinal sectional view of a lamp main
`body 1 of a headlamp according to another embodiment
`of the present invention. The lamp main body 1 is ac-
`commodated in a lamp body similar to a lamp body 2
`shown in FIG. 9 and is mounted on a vehicle body. A
`convex lens 6 is mounted in front of a reflecting mirror
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`4 having a reflecting face 3 of an ellipsoid of revolution
`by way of a connecting frame member 5, and optical
`axes X of the reflecting mirror 4 and convex lens 6
`coincide with each other. Reference numeral 7 denotes
`a bulb, and a filament 8 which serves as a light source of
`the bulb 7 is positioned at a first focus F1 of an ellipse
`forming the reflecting face 3. Reference character F2
`denotes a second focus of the ellipse, and in the present
`embodiment, the second focus F2 is positioned on an
`incidence face of the convex lens 6.
`Reference character F3 denotes a focus of the convex
`lens 6, and the central point 9c of an upper edge of a
`light stopping plate 9 is positioned at the focus F3. The
`light stopping plate 9 extends in leftward and rightward
`directions as shown in FIG. 6. Then, while a left-hand
`side (left as facing the convex lens 6 side from the re-
`flecting mirror 4 side, this similarly applies to the fol-
`lowing description) upper edge 9a extends horizontally
`at the same height as the central point 9c, a right-hand
`side upper edge 9b is inclined downwardly from the
`central point 9c. A mounting portion 9d which is bent
`rearwardly, that is, toward the reflecting mirror 4 side is
`formed integrally on a lower edge of the light stopping
`plate 9, and the mounting portion 9117 is secured to a gear
`plate 10 at a rear position by means of screws 11.
`The gear plate 10 has a sectoral shape having a size
`sufficient to cover an entire lower half portion of a
`transverse section of the lamp main body 1, and left and
`right upper edges 10a and 10b of the gear plate 10 are
`set lower than the upper edges 9a and 9b of the light
`stopping plate 9, respectively. At a central portion of
`the upper edge of the gear plate 10, that is, at a portion
`located behind the central point 9c of the light stopping
`plate 9, a bearing hole 12 is provided which has an axial
`line coincident with the optical axis X, and in order to
`provide the bearing hole 12, a projected portion 13 is
`formed at the portion.
`A support post member 14 secured at a lower end
`thereof to a lower portion of an opening edge of the
`reflecting mirror 4 is provided uprightly behind the
`gear plate 10. An upper end of the support member 14
`is located rearwardly of the projected portion 13 of the
`gear plate 10, and a bearing hole 15 aligned with the
`aforementioned bearing hole 12 is provided at the por-
`tion. Then, a pivot shaft 16 is fitted in the bearing holes
`12 and 15, thereby forming bearing section 17 for sup-
`porting the gear plate 10 for tilting motion on the sup-
`port post member 14. The gear plate 10 is held in mesh-
`ing engagement at a lower portion thereof with a drive
`gear 19 which is driven by a servomotor 18. Accord-
`ingly, by operating the servomotor 18, the gear plate 10
`can be tilted around the axial line of the bearing section
`17, that is, around the optical axis X, and the light stop-
`ping plate 9 is tilted around the optical axis X passing
`the central point 9c of the upper edge of the light stop-
`ping plate 9 in response to such tilting motion of the
`gear plate 10.
`If the light source is a point light source positioned at
`the first focus F; of the reflecting face 3, then reflected
`light from an upper half portion of the reflecting face 3
`is focused upon the second focus F2 past a location
`above the light stopping plate 9 as indicated by solid
`line arrow marks l1 and 12, and then goes Out forwardly
`by way of a lower half portion of the convex lens 6.
`Meanwhile, reflected light from a lower half portion of
`the reflecting face 3 is stopped interrnediately by the
`light stopping plate 9 and the gear plate 10 and will not
`reach the second focus F2, and consequently, no light
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`exists which goes out forwardly through an upper half
`portion of the convex lens 6. Accordingly, a distribution
`pattern is obtained wherein an upper portion is a dark
`portion while a lower half portion is a bright portion.
`However, since the filament 8 actually has a cylindrical
`shape, the light source is not a point light source, and
`consequently, also such a reflected beam of light as, for
`example, indicated by a chain line arrow mark 13 exists,
`and besides such beams of light also exist which have
`been irregularly reflected by various portions in the
`lamp main body 1. Since also such light is projected
`forwardly through the convex lens 6,
`if only ideal
`beams of light (beams of light corresponding to 11 or l2
`mentioned above) from the lower half portion of the
`reflecting face 3 are stopped, a light distribution pattern
`wherein a boundary line between a dark portion and a
`bright portion is clear cannot be obtained.
`Thus, the light stopping plate 9 is disposed at the
`position of a focus of the convex lens 6 so that real
`images of the upper edges 9a and 912 may be formed on
`a projection plane in order that a sharp bright/dark
`boundary line may be obtained. In other words, a light
`distribution pattern is formed by an enlarged image of a
`plane F passing the focus F3 by the convex lens 6. While
`a real image of a body placed at the focus of the convex
`lens 6 is theoretically formed at infinity forwardly of the
`lens, if the light projection plane is spaced sufficiently
`from the lens, then the degree of an out-of-focus condi-
`tion of an image is low, and an actually acceptable clear
`image can be obtained. Then, if the light stopping plate
`9 is tilted around the optical axis X by the bearing sec-
`tion 17, then the image is also tilted so that the distribu-
`tion pattern is changed.
`By the way, since the bearing section 17 is projected
`upwardly above the upper edges 9a and 9b of the light
`stopping plate 9, an enlarged real image of the bearing
`section 17 is formed by the convex lens 6, and if the
`bearing section 17 is in the plane F, then the image must
`be overlapped with the image of the light stopping plate
`9 and a dark portion originating from the image of the
`bearing section 17 must project downwardly from a
`central portion of a bright/dark boundary line formed
`by the images of the upper edges 9a and 9b similar to
`that shown in FIGS. 13a, 13b. However, in the present
`embodiment, since the position of the bearing section 17
`is displaced rearwardly from the focus F3, a real image
`of the bearing section 17 is formed at a considerably
`near position forwardly of the convex lens 6, and as the
`distance forwardly from the position increases,
`the
`image is rapidly put
`into an out-of-focus condition.
`Then at a remote position, the difference in brightness
`by the image disappears, and only a clear bright/dark
`boundary line originating from the upper edges 90 and
`9b of the light stopping plate 9 remains. FIG. 8a shows
`a light distribution pattern obtained when light from the
`convex lens 6 is projected on a screen erected perpen-
`dicularly to the optical axis X at a location of a certain
`distance forwardly of the lens. A dark portion 21 and a
`bright portion 22 are sectioned clearly by a bright/dark
`boundary line 20a originating from the upper edge 9a of 60
`the light stopping plate 9 and another bright/dark
`boundary line 20b originating from the upper edge 9b. If
`the location of the screen is nearer to the convex lens 6,
`images b and g of the bearing section 17 and gear plate
`10 appear as indicated by a broken line g, and the por-
`tion becomes dark. However, if the screen is spaced far
`away from the convex lens 6, then the dark portion
`disappears due to an out-of-focus condition of the image
`
`8
`and is put into a similarly bright condition as the bright
`portion 22 adjacent thereto. Accordingly, on an actual
`road, a right distribution condition is obtained wherein
`the dark portion 21 and the bright portion 22 are sec-
`tioned very clearly by the bright/dark boundary lines
`200 and 20b as shown in FIG. 8b.
`In the present embodiment, the light stopping plate 9
`is supported by means of the bearing section 17 on the
`optical axis X which is an axial line of tilting motion
`thereof, and the light stopping plate 9 need not be sup-
`ported at an outer peripheral portion thereof spaced
`from a route of light. and for tilting motion around an
`optical
`axis
`as
`in the conventional arrangement,
`whereby the supporting structure for the light stopping
`plate is simplified and miniaturized remarkably.
`It is to be noted that, while there must be no influence
`of an image of the bearing section 17 upon alight distri-
`bution pattern eve if the bearing section 17 is provided
`forwardly of the light stopping plate 9, that is, on the
`convex lens 6 side, this is not preferable because, in this
`instance, beams of light which are to be introduced into
`the convex lens 6 by way of routes different from those
`of the ideal beams of light 11 and 12 such as a beam of
`light l3 are stopped by the bearing section 17, gear plate
`10, support post member 14 and so forth.
`FIG. 9 is a drawing similar to FIG. 5 described above
`but showing another embodiment of the present inven-
`tion, and like reference numerals are applied to like
`portions to those of FIG. 5. In FIG. 9, a lamp body 2
`which is omitted in FIG. 5 is also shown. The lamp
`body 2 is secured to a vehicle body frame not shown by
`way of a suitable support arm, and a cover lens 23 for
`passing emergent beams of light from the convex lens 6
`therethrough is fitted in an opening at a front portion of
`the lamp body 2. The present embodiment is different
`from the preceding embodiment described above in that
`a light stopping plate 9 and a gear plate 10 are formed as
`an integrated member. Then, a support post member 14
`is provided along a rear face of the gear plate 10, and an
`end of a pivot shaft 16 extending through a bearing hole
`12 of the gear plate 10 is screwed into the support post
`member 14 so that
`the gear plate 10 may be tilted
`around the pivot shaft 16. The support post member 14
`is secured to the lamp body 2 together with a servomo-
`tor 18, and a drive gear 19 secured to an output shaft of
`the servomotor 18 is held in meshing engagement with
`the gear plate 10. Reference numeral 24 denotes a worm
`wheel which is used to manually tilt the gear 10 upon
`adjustment or the like.
`Although there have been described what are at pres-
`ent considered to be the preferred embodiments of the
`present invention, it will be understood that the inven-
`tion may be embodied in other specific forms without
`departing from the essential characteristics thereof. The
`present embodiments are therefore to be considered in
`all aspects as illustrative, and not restrictive. The scope
`of the invention is indicated by the appended claims
`rather than by the foregoing description.
`What is claimed is:
`1. A headlamp having a light distribution changing
`device wherein light from a light source is reflected by
`a reflecting mirror and then projected forwardly by
`way of a convex lens, said light distribution changing
`device being constituted such that a light stopping plate
`for stopping a part of light advancing from said reflect-
`ing mirror toward said convex lens is provided between
`said light source and said convex lens and the light
`distribution is changed by tilting said light stopping
`
`45
`
`50
`
`S5
`
`65
`
`11
`
`11
`
`

`
`9
`plate around an optical axis; characterized in that said
`light stopping plate is provided at a position of a focus
`of said convex lens on a side facing said reflecting mir-
`ror and a bearing for supporting said light stopping
`plate for tilting motion thereon is provided on the opti-
`cal axis in a displaced relationship to a said facing said
`reflecting mirror with respect
`to said light stopping
`plate.
`2. A headlamp claimed in claim 1, wherein said light
`distribution changing device comprises a gear plate
`positioned at said side facing said reflecting mirror side
`with respect to said light stopping plate, fixed to said
`light stopping plate and meshing with a drive gear; a
`support post member positioned at said side f