JP3104035B2 - Automotive headlamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a headlamp using a discharge bulb and, more particularly, to a vehicle equipped with a discharge bulb which can form both a sub beam and a main beam by moving a movable lens toward and away from the bulb. Related to headlamps.

[0002]

2. Description of the Related Art A discharge bulb of the type which emits light by discharge between electrodes has no problem of disconnection unlike a bulb of the type which emits filament, and a large amount of light can be obtained with less power consumption than a filament type. From this point, recently, it has been receiving attention as a headlamp bulb. Japanese Unexamined Utility Model Publication No. Hei 3-68302 has proposed a headlamp in which two different light distributions of a main beam and a sub-beam are formed by one discharge bulb.

As shown in FIG. 10, the headlamp is provided with a shade 3 swinging in the front-rear direction of the optical axis in front of the discharge bulb 2, and when the shade 3 is located forward (from the bulb 2). (When separated), the light emission of the bulb 2 is reflected by the entire effective reflection surfaces 1a and 1b of the reflector 1, and a light distribution pattern of a main beam as shown in FIG. 11 is formed, and the shade 3 is positioned rearward. At this time (when approaching the bulb 2), the shade 3 blocks a part of the light emitted from the bulb 2, and the sub-beam distribution as shown in FIG. It has a structure in which an optical pattern is formed.

[0004]

However, the conventional structure described above has a problem that the light is not effectively used because the light directed to the area denoted by reference numeral 1b is blocked by the shade 3 when the sub-beam is formed. . SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a headlamp for an automobile which uses a discharge bulb as a light source and moves a movable lens to form two light distributions of a main beam and a sub-beam. It is another object of the present invention to provide a headlamp that makes effective use of the light emission of a discharge bulb as much as possible.

[0005]

In order to achieve the above object, in a vehicle headlamp according to the present invention, a first part of an upper region of a bulb insertion hole formed in a lamp body is provided.
From the reflection paraboloid and the area below the valve insertion hole.
A parabolic reflector having a substantially U-shaped second reflective parabolic surface that opens upward when viewed from the front and extends to the left and right outer regions of the reflective parabolic surface; A discharge bulb, which is a light source disposed to be in the vicinity of the discharge bulb; and a front-rear approach and separation operation with respect to the discharge bulb so as to alternatively take a front position of the discharge bulb or a rear position surrounding the discharge bulb. A movable lens having a cylindrical shape, wherein the movable lens has an opening having a shape corresponding to the first reflective paraboloid when the movable lens is at the rear position, and is formed near the rear thereof; Movable
Prism step for refracting outgoing light downward substantially entire region corresponding to the second paraboloidal reflecting surface of the lens is formed, prior to
The front opening of the movable lens is directly in front of the discharge bulb.
At the front position where the movable lens is separated from the discharge bulb, light emission of the discharge unit directly irradiates the first and second reflective paraboloids of the reflector at a front position where the movable lens is separated from the discharge bulb ,
The main beam is formed by the light reflected on both reflection paraboloids, and at the rear position where the movable lens approaches the discharge bulb,
A part of the light emitted from the discharge unit directly irradiates the first reflective paraboloid of the reflector, and a part of the light emitted is refracted through the movable lens and guided to the second reflective paraboloid , Anti-reflection on both reflective paraboloids
It is obtained by configuration so that the sub-beams formed by Shako.

[0006]

In the forward position where the movable lens is separated from the bulb, the light of the bulb directly shines on the first and second reflective paraboloids, and the light distribution pattern of the main beam is formed by the first and second reflective paraboloids. It is formed. On the other hand, at the rear position where the movable lens approaches the bulb, the direct light of the bulb is guided to the first reflection paraboloid, but is provided on the movable lens to the second reflection paraboloid.
The light adjusted downward by the prism step is guided, and the light distribution pattern of the sub beam is formed by moving the central region of the light distribution pattern of the main beam downward in the left-right direction.

[0007]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 6 show one embodiment of the present invention. FIG. 1 is a perspective view of a headlamp with a front lens removed, FIG. 2 is a longitudinal sectional view of the headlamp, and FIG. FIG. 4 is an enlarged transverse sectional view of the movable lens (an enlarged sectional view taken along line IV-IV shown in FIG. 3).

In these figures, reference numeral 10 denotes a container-shaped lamp body which is opened forward, and a parabolic reflector 12 formed by aluminum vapor deposition is integrally formed on the inner peripheral surface. A bulb insertion hole 14 is formed at the rear top of the reflector 12, and a discharge bulb 20 that emits light by discharging between the electrodes is inserted therein. Reference numeral 21 denotes a discharge unit, and reference numeral 22 denotes an ultraviolet blocking glove for cutting ultraviolet light in a predetermined wavelength range harmful to a human body or the like from light emission of the discharge unit 21, and is fixed to an insulating base 23. The parabolic effective reflection surface of the reflector 12 includes a first reflection parabolic surface 12A having a substantially rectangular front shape formed above the valve insertion hole 14 and a first reflection paraboloid 12A from the lower side of the valve insertion hole 14. The front shape extending to the left and right of the reflective paraboloid 12A opens upward.
Substantially consisting of a second paraboloidal reflecting surface 12B of the U-shaped that. Reference numeral 16 in FIG. 2 denotes a front lens mounted on the front opening of the lamp body 10, and the light reflected by the effective reflection surface of the reflector 12 and guided forward on the rear surface of the front lens 16 in an appropriate direction. A diffusion step (not shown) for adjusting the height is formed.

First and second reflective paraboloids 12A, 12B
Have the same paraboloid shape with the same focal length, but the focal position of the second reflective paraboloid 12B is the first reflective paraboloid 1
The second reflection paraboloid 12B is located forward of the focal position of 2A, that is, the second reflection paraboloid 12B extends forward from the first reflection paraboloid 12A by a parabola (indicated by 12C in FIG. 2) in the optical axis direction. And a step 13 corresponding to the parallel movement distance d is formed between the two reflective paraboloids 12A and 12B. Then, light from the discharge portion 21 of the bulb 20 is reflected by the reflecting paraboloids 12A and 12B of the reflector to form a light distribution pattern of a main beam and a sub-beam. The main beam is reflected by the two reflecting paraboloids 12A and 12B. And the sub-beam is formed by a first reflective paraboloid 12
A is formed by the direct reflected light at A and the indirect reflected light at the second reflector 12B.

That is, in front of the bulb 20, it slides in the front-rear direction of the optical axis L to block light traveling forward from the discharge part 21 and, when it comes to a position close to the bulb 20, the second reflection of the reflector. A movable lens 30 for adjusting the direction of light traveling toward the paraboloid 12B is provided. The movable lens 30 is a glass lens body 3 that is opened upward with a rear upper half region of a horizontally disposed cylinder cut out.
2 and integrated with the front end opening of the lens body 32,
The lens body 32 includes a disk-shaped light shielding plate 34 that blocks light emitted forward from the front end opening. A prism step 33 (33a, 33) for refracting light emitted from the cylindrical portion downward is provided on the outer peripheral surface of the cylindrical lens body 32.
b, 33c, 35d, 35e, 35f) are formed.

[0011] Prism step 33 (33a-33f)
As shown in FIG. 4, is formed in a step shape in which light incident into the lens body cylindrical portion from the discharge portion 21 of the bulb is refracted downward when emitted. The shape of the rear upper opening 32a formed in the lens body 32 is
It is formed in a shape (a shape corresponding to the first reflective paraboloid 12A) corresponding to a position where the step 13 is formed, which is a boundary line between the first reflective paraboloid 12A and the second reflective paraboloid 12B. .
That is, the rear upper opening portion 32a of the lens body 32 is provided with the first reflection paraboloid 1 from the discharge portion 21 when the movable lens 30 approaches the bulb 20 and reaches the position covering the discharge portion 21.
2A, the lens body 32 is positioned on the optical path of light from the discharge section 21 to the second reflective paraboloid 12B, and the discharge section 2
Downwardly adjusted to from 1 Did light toward the second reflective paraboloid 12B was as if emitted from P ₁ above the point P ₂ point on the optical axis L. Then, the downwardly adjusted light is reflected by the reflection paraboloid 12B, and forms a light distribution pattern indicated by the symbol Pbs in FIG. 6 below the horizontal level H position of the light distribution screen.

More specifically, when the light from the discharge unit 21 directly impinges on the second reflective paraboloid 12B without passing through the lens body 32, the second reflective paraboloid 12
B forms a light distribution pattern Pbm shown in FIG. 5 on the horizontal level H of the light distribution screen, which is too upward for the sub-beam and glare (harmful light) for oncoming vehicles. Therefore, the light emitted from the discharge unit 21 is transmitted through the prism step 33 of the lens body 32 to adjust the light traveling toward the second reflection paraboloid 12B downward, and is formed by the reflection of the second reflection paraboloid 12B. The light distribution pattern Pbm does not become harmful light.
Is shifted to the lower position shown in FIG.

FIG. 5 shows the light distribution pattern of the main beam, while FIG. 6 shows the light distribution pattern of the sub beam.
am and Pas are light distribution patterns formed by the first reflection paraboloid 12A, and symbols Pbm and Pbs are light distribution patterns formed by the second reflection paraboloid 12B. It is a light distribution pattern of a sub beam.

Reference numeral 40 denotes a slide mechanism for sliding the movable lens 30 in the front-rear direction of the optical axis L. A ball screw 42 disposed in the front-rear direction, a driving motor 43 for driving the ball screw 42 to rotate, and a ball screw 42 , A slide unit 45 attached to both the ball screw 42 and the guide rod 44, and legs 46 erected on the slide unit 45 and supporting the movable lens 30. . And ball screw 4
The forward / reverse rotation of 2 causes the slide unit 45 to slide back and forth, whereby the movable lens 30 can selectively take the sub-beam forming position close to the bulb 20 and the main beam forming position separated from the bulb 20.

In FIGS. 5 and 6, the light distribution pattern on the light distribution screen 4
The illuminance at a position inclined at an angle (indicated by the symbol P4D-V) tends to be somewhat too high. Therefore, a diffusion step for controlling the light distribution of the front lens 16 mounted on the front opening of the lamp body 10 by reducing the vertical width of the effective reflection surface above the bulb insertion hole 14, that is, the first effective reflection surface 12A, is performed. By modifying the light distribution pattern, a light distribution pattern with reduced illuminance at the point P4D-V may be formed as shown in FIGS.

FIG. 9 is a cross sectional view of a movable lens which is a main part of another embodiment of the present invention. In the above-described embodiment, the prism steps 33 (33a to 33f) for adjusting the direction of the emitted light downward are formed outside the lens body 32, but in the present embodiment, the direction of the emitted light is formed inside the cylindrical portion 32. Step 33 (33a-33) for adjusting
The difference is that f) is formed.

[0017]

As is apparent from the above description, according to the headlamp according to the present invention, when the movable lens is in the forward position away from the discharge bulb, the light from the bulb reflects the first and second paraboloids of reflection. And the light distribution pattern of the main beam is formed by the first and second reflection paraboloids. At the rear position where the movable lens approaches the discharge bulb, the light of the bulb is first.
The light adjusted downward by the prism step of the movable lens is guided to the second reflective paraboloid, and the light is distributed downward through the central region in the left-right direction of the main beam light distribution pattern. As the light distribution pattern of the sub-beam moved to the sub-beam is formed, the light emission of the discharge bulb is effectively used for the light distribution of the sub-beam as well as the light distribution of the main beam. A headlamp having characteristics is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of an automotive headlamp according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the headlamp.

FIG. 3 is a horizontal sectional view of the headlamp.

FIG. 4 is an enlarged cross-sectional view of the movable lens (a line IV-
(Enlarged cross-sectional view along IV) to illustrate how the emitted light is refracted

FIG. 5 is a diagram showing a light distribution pattern of a main beam.

FIG. 6 is a diagram showing a light distribution pattern of a sub beam.

FIG. 7 is a view showing a light distribution pattern of a main beam according to another embodiment of the present invention.

FIG. 8 is a diagram showing a light distribution pattern of a sub beam according to another embodiment of the present invention.

FIG. 9 is an enlarged cross-sectional view of a movable lens which is a main part of still another embodiment of the present invention.

FIG. 10 is a perspective view of a conventional headlamp.

FIG. 11 is a diagram showing a light distribution pattern of a main beam of a conventional headlamp.

FIG. 12 is a diagram showing a light distribution pattern of a sub-beam of a conventional headlamp.

[Explanation of symbols]

 Reference Signs List 10 lamp body 12 reflector 12A first reflective paraboloid 12B second reflective paraboloid 20 discharge bulb 21 discharge unit 30 movable lens 32 cylindrical lens body 32a opening corresponding to first reflective paraboloid 33 (33a-33f) Prism step 40 movable lens slide mechanism

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F21S 8/10 F21V 5/00 F21V 7/09 F21V 14/00

Claims (1)

(57) [Claims] 1. A front surface formed in a lamp body and extending from a first reflection parabolic surface in an upper region of a bulb insertion hole and a left and right outer region of the first reflection paraboloid from a lower region of the bulb insertion hole. A parabolic reflector having a substantially U-shaped second reflective paraboloid that opens upward when viewed from above; and a light source in which a discharge unit, which is a light emitting source, is located at a position near the focal point of the reflector. A discharge bulb; and a movable lens having a cylindrical shape that moves toward and away from the discharge bulb in the front-rear direction so as to alternatively take a front position of the discharge bulb and a rear position surrounding the discharge bulb. When the movable lens is at the rear position, an opening having a shape corresponding to the first paraboloid of reflection is formed near the rear portion, and an opening in front of the movable lens is formed.
A prism step for refracting outgoing light downward is formed in substantially the entire area corresponding to the second reflective paraboloid, and the movable lens is formed.
Front opening directly from the discharge bulb
At the front position where the movable lens is separated from the discharge bulb , a light-shielding member for blocking light is provided, and the light emitted from the discharge unit directly shines on the first and second reflection paraboloids of the reflector.
At the rear position where the movable lens approaches the discharge bulb, part of the light emitted from the discharge part directly irradiates the first reflective paraboloid of the reflector and part of the light emitted at the rear position where the movable lens approaches the discharge bulb. A headlamp for an automobile, wherein the headlamp is refracted and transmitted through a movable lens and is guided to a second reflection paraboloid, and a sub-beam is formed by light reflected on both reflection parabolas .