JPH0720801Y2 - Variable diffusion angle lamp device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to improvement of a diffusion angle variable type lamp that can vary the diffusion angle of irradiation light, and particularly to prevent light beam splitting during spot irradiation and diffuse irradiation. The present invention relates to a variable diffusion angle type lamp device which is improved and has excellent visibility as a vehicle lamp such as a vehicle headlamp.

[Conventional technology]

Conventionally, in vehicular lamps such as automobile headlights,
As shown in FIG. 9 and FIG. 9, a plurality of cylindrical lens steps are provided at a constant equal pitch on the front optical axis of a means such as a projector lamp or a reflector which makes a light flux from a light source parallel to the optical axis L. By providing two moving lenses 51 and a fixed lens 52, and changing the interval between the two lenses 51 and 52 continuously or stepwise, the focal points F1 and F2 of the lens steps of the two lenses 51 and 52 are made relative to each other. Move (direction of arrow A)
There is known a variable diffusion angle type lamp device that changes the diffusion of a light flux in the horizontal direction.

[Problems to be solved by the device]

However, in this type of variable diffusion angle type lamp device, since the light flux from the light flux collimating means is not a point light source, the total light flux L1 is not parallel, and an inclined light flux L2 is also emitted. Therefore, in the conventional lamp device of this type,
As shown in FIG. 5A, the lens steps of both lenses 51 and 52 are formed at equal pitches, and the focal points F1 and F2 are formed to have the same distance (H1 = F2). Five
Although it is intended to perform spot irradiation by matching the focal points F1 and F2 of 1,52, the inclined light flux L2 that has passed through the moving lens 51 enters the lens step next to the fixed lens 52, and As shown in FIG. 8 (b), sub-irradiation patterns S2 and S2 appearing on both sides of the main irradiation pattern S1 appear,
So-called beam cracking occurs.

Further, as shown in FIG. 9 (a), when the lenses 51 and 52 are separated from each other and the focal points F1 and F2 are displaced to perform diffused irradiation, the outer light flux L2 that has passed through the moving lens 51 is fixed lens. When incident on the lens step adjacent to 52, sub-irradiation patterns S3 and S3 appear on both sides of the main irradiation pattern S1 as shown in FIG. 9 (b), and beam splitting occurs also in this case.

Therefore, for example, when used as a vehicle headlight,
A side-diffused light flux generated as a sub-irradiation pattern partially illuminates a road surface, a shoulder, a guardrail, or the like brightly, which makes it difficult to drive at night.

The present invention has been made in view of the above problems, and an object thereof is to provide a variable diffusion angle type lamp device capable of varying the diffusion angle of irradiation light without causing beam cracking. .

[Means for Solving the Problems]

In order to achieve the above object, a variable diffusion angle type lamp device according to the present invention comprises two lenses each having a large number of cylindrical lens steps arranged at equal pitches on the front optical axis of a light beam collimating means. In a light distribution variable type lamp device that is provided and changes the distance between both lenses to change the irradiation distribution of the irradiation light beam, the focal length of the lens step of the two lenses is the focal length of the lens on the light beam collimating means side. However, in addition to the focal length of the other lens, the distance between both lenses is adjusted so that the distance is not larger than twice the focal length of the lens on the light beam collimating means side. To do.

Of course, the cylindrical lens step formed of the two lenses may be a convex lens step and a convex lens step, or a combination of a convex lens step and a concave lens step.

[Action]

That is, when the focused irradiation is performed by the two lenses positioned in front of the parallel light flux, the objective is achieved by making the focal points of both lenses coincide, but the lens steps of both lenses have equal pitches. Therefore, when the focal points of both lens steps having different focal lengths are matched, the light beam incident width becomes narrower as the focal length becomes shorter. Therefore,
According to the configuration of the present invention in which the focal length of the lens on the side of the light beam collimating means is set to be larger than the focal lengths of the other lenses, the light beam is transmitted to the lens step of the lens located in front. Irradiation is carried out through a part of the range, and the entire light side incident from the lens step of the lens on the light beam collimating means side can be transmitted by the corresponding lens step, and enters the adjacent lens step. There is nothing to do.

Therefore, it becomes possible to eliminate the conventional beam splitting phenomenon that occurs when a light beam enters the out-of-support lens step.

〔Example〕

An embodiment of a variable diffusion angle type lamp device according to the present invention will be described below with reference to the drawings.

FIGS. 1 to 4 show a first embodiment in which a projector lamp is used as a light beam collimating means. FIG. 1 is a partially cutaway plan sectional view of a headlamp, and FIG. FIG. 2 is a sectional view taken along line II-II in FIG. 1.

In both figures, the hood 6 provided on the front surface of the casing 5 and the projector lamp 3 provided at the rear end of the casing 5 constitute a lamp chamber 4.

A movable lens 1 and a fixed lens 2 are fixed in the lamp chamber 4 so as to be orthogonal to the optical axis L, and the fixed lens 2 located on the hood 6 side has a large number of cylindrical convex lens steps 9 and 9. Are arranged side by side in the lateral direction, and the focal length is formed by forming each convex lens step 9 at a pitch P2
The structure has f2. Further, the movable lens 1 is located on the optical axis L between the fixed lens 2 and the collimator lens 17, and is composed of a large number of cylindrical convex lens steps 7, 7 ... The moving lens 1 is a convex lens step of the fixed lens 2.
9 and 9 are formed by convex lens steps 7 having an equal pitch P1 (P1 = P2), and each of the convex lens steps 7 has a focal length f1 (f1> longer than the focal length f2 of the fixed lens 2).
It has a structure with f2).

The lens moving means 8 of the moving lens 1 is the moving lens 1
A rack 11 projecting from a side wall of the casing 5 is projected through a lens frame 10 that supports
11 is engaged with a worm 13 axially attached to the drive shaft of the step motor 12, and the movable lens 1 is displaced in the axial direction (arrow A) by the control drive of the step motor 12.

In the projector lamp 3, a light source 14 for lighting a bulb or the like is provided at a first focal point F3 position on an elliptical mirror surface of a reflector 15, and a shielding plate 16 having a small hole is provided at a second focal point F4 position. The collimator lens 17 sharing the second focus F4 position is provided on the front surface, which has a known structure, and the luminous flux emitted from the projector lamp 3 is parallel to the optical axis L.

In the variable diffusion angle type lamp device having the above-mentioned configuration, the stepping motor 12 is rotated forward and backward via a controller (not shown) to move the movable lens 1 to a predetermined change position (arrow A).

When the step motor 12 is driven to rotate, the worm 13 and rack 1
Lens frame 1 that is integrated with the rack 11 via 1
0 moves in the direction of arrow A along the inner wall of the casing 5.
By this movement, the relative position of the moving lens 1 to the fixed lens 2 is displaced, and the convex lens steps 7 and 9 of both lenses 1 and 2 are displaced.
The irradiation light can be changed to spot irradiation light or diffusion irradiation light depending on the relationship with the focal positions F1 and F2.

Next, the operation of the lamp device having the above configuration will be described with reference to FIGS. 3 and 4.

FIG. 3 shows the relationship between the positions of both lenses 1 and 2 and the light flux at the time of converging irradiation. At this time, the focus F of both lenses 1 and 2 is
1, F2 position overlap, and the distance between both lenses is D (D = f1 + f2)
The movable lens 1 is adjusted and moved so that That is, since the parallel light flux from the projector lamp 3 that has entered the moving lens 1 is focused on the focal points F1 and F2 that are overlapped by the lens step 7 of the moving lens 1, the forward irradiation light flux refracted by the lens step 9 of the fixed lens 2 is collected. L1 forms a focused irradiation pattern parallel to the optical axis L. Both lenses at this time
Focal lengths f1 and f2 in lens steps 7 and 9 of 1 and 2
Is configured so that f1> f2, the moving lens 1
The light flux incident on the entire width W1 of the lens step 7 of the fixed lens 2 is incident on the lens step 9 of the fixed lens 2 with the width W1, and the width W1 of the light flux is the total width of the lens step 9 W2. Since (P1 = P2), the entire light beam is refracted within a range W3 (W2> W3) smaller than the width W2 of the lens step 9. Therefore, as shown by the broken line in FIG.
An allowable area for accommodating the outward light flux from the moving lens 1 at one pitch P2 of the lens step 9 is formed, and a light flux emitted from the projector lamp 3 of the light flux collimating means is partially inclined with respect to the optical axis L. Beam cracking does not occur even if the L3 with is included.

FIG. 4 shows the relationship between the positions of both lenses 1 and 2 and the light flux during diffuse irradiation. At this time, the focal points F1 and F2 of both lenses 1 and 2 are shown.
The movable lens 1 is adjusted and moved so that the F2 positions do not overlap and the distance D between the lenses becomes smaller than twice the focal length f1 of the movable lens 1 (D <2 × f2). That is, the moving lens 1
The parallel light flux from the projector lamp 3 that has entered the lens is focused at the focal point F1 by the lens step 7 of the moving lens 1, but the focal point F2 of the fixed lens 2 is deviated, so the luminous flux L2 that has passed through the lens step 9 is bidirectional. To form a diffused irradiation pattern. Even in this case, both lenses 1, 2
Since the lens steps 7 and 9 are equal to each other, the light flux incident on the entire width W1 of the lens step 7 of the moving lens 1 is incident on the lens step 9 of the fixed lens 2 with the width of W3. The width W3 of is the entire width of the lens step 9
Since W2 (P1 = P2), the structure is such that all light beams are refracted within a range smaller than the width W2 of the lens step 9. Therefore, as shown by a broken line in FIG. 4, an allowable area for accommodating the outward light flux from the moving lens 1 in one pitch P2 of the lens step 9 is formed, and the light is collimated and is emitted from the projector lamp 3. Even if a part of the luminous flux L3 having an inclination with respect to the optical axis L is included, beam cracking does not occur.

As described above, the variable diffusion angle lamp device according to the present invention can achieve the object by the relationship between the focal lengths f1 and f2 of the convex lens steps 7 and 9 of the movable lens 1 and the fixed lens 2. However, it is needless to say that it is possible to carry out by a combination of two lenses, which have a convex lens step and a concave lens step optically utilizing the same principle, and next, the principle will be described with reference to FIGS. 5 and 6. explain.

FIG. 5 shows the relationship between the positions of the moving lens 21 and the fixed lens 22 and the luminous flux at the time of converging irradiation. At this time, the focal points F1 and F2 positions of both lenses 21 and 22 are overlapped, and the distance between the two lenses is D
The moving lens 21 is adjusted and moved so that (f1> f2).
That is, since the parallel light flux from the projector lamp 3 that has entered the moving lens 21 is focused on the focal points F1 and F2 that are overlapped by the lens step 27 of the moving lens 21, the fixed lens 22
Forward irradiation light flux L1 refracted by lens step 29 of
Form a focused irradiation pattern parallel to the optical axis L.
At this time, in lens steps 27 and 29 of both lenses 21 and 22,
Since the focal lengths f1 and f2 are set to be f1> f2, the light flux incident on the full width W1 of the lens step 27 of the moving lens 21 is W3 to the lens step 29 of the fixed lens 22. Since the lens step 29 has a width W3 of which the total width of the lens step 29 is W2 (P1 = P2), the entire light beam is refracted within a range smaller than the width W2 of the lens step 29. .

FIG. 6 shows the relationship between the positions of the movable lens 21 and the fixed lens 22 and the luminous flux at the time of diffuse irradiation. At this time, the focal points F1 and F2 of the two lenses 21 and 22 do not overlap each other, and the distance between the two lenses is not increased. The moving lens 21 is adjusted and moved so that the distance D becomes smaller than twice the focal length f1 of the moving lens 21 (D <2 × f2). That is, the parallel light flux that has entered the moving lens 21
Although the light is condensed at the focal point F1 by the lens step 27, the light flux L2 transmitted through the lens step 29 is diffused in both directions because the focal point F2 of the fixed lens 22 is deviated, forming a diffused irradiation pattern. Even in this case, since the lens steps 27 and 29 of both lenses 21 and 22 are the same and the focal lengths have a relationship of f1> f2, the light flux incident on the full width W1 of the lens step 27 of the moving lens 21 is the lens of the fixed lens 22. For step 29, it will be incident with a width of W3.
The structure is such that all light beams are refracted within a range smaller than the width W2 of 29.

Further, FIG. 7 shows an embodiment of the present invention having other light beam collimating means, which constitutes a parabolic mirror as the reflector 30 and is equipped with a light source 31 for lighting at its focal position F3. On the optical axis L, a convex lens step 7 similar to that in the above embodiment,
It has a construction in which a movable lens 1 having 9 and a fixed lens 2 are provided, and since the operation is the same as that of the above-mentioned embodiment, its explanation is omitted.

Although the lens moving means 8 is configured on the moving lens 1 side in the above embodiment, it may be provided on the fixed lens 2 side. Further, it goes without saying that the lens moving means 8 can be implemented by various known techniques.

[Effect of device]

Since the variable diffusion angle type lamp device according to the present invention is configured as described above, the focal position of the cylindrical lens step, which is configured by two lenses whose relative positions are variable in the optical axis direction, is set to the first lens. Since the transmitted light flux is configured to enter within a smaller range than the second lens step, beam splitting does not occur and the light flux diffused to the side is eliminated even when used as a vehicle headlight. In addition, the lighting has a feature that stable driving is possible and safe driving is possible, and the practical effect after implementing the present invention is extremely large.

[Brief description of drawings]

FIG. 1 is a plan sectional view showing a first embodiment of a variable diffusion angle type lamp device according to the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. FIG. 4 is an explanatory view showing the position of the lens of FIG. 4, FIG. 4 is an explanatory view showing the position of the lens at the time of diffused irradiation, and FIG. 5 is an explanatory view showing the position of the lens at the time of focused irradiation showing another lens combination. FIG. 6 is an explanatory view showing the position of the lens at the time of diffused irradiation, FIG. 7 is a plan sectional view showing another embodiment of the present invention, and FIGS. 8 and 9 are conventional lens combinations (a). ) And its irradiation pattern (b). 1,21 …… Movement lens 2,22 …… Fixed lens 3 …… Projector lamp 7,9 …… Convex lens step 8 …… Lens moving means 30 …… Reflector 31 …… Light source

Claims (2)

[Scope of utility model registration request] 1. A pair of lenses, each having a large number of cylindrical lens steps arranged in parallel at equal pitches, are provided on the front optical axis of the beam collimating means, and the relative distances of both lenses in the optical axis direction are changed. In the variable light distribution type lamp device for changing the irradiation distribution of the irradiation light flux, the focal length of the lens step of the two lenses is set such that the focal length of the lens on the light beam collimating means side is greater than the focal length of the other lens. The variable diffusion angle type is characterized in that it is configured to be large and is configured to be movable and adjusted within a range in which the distance between both lenses is not larger than twice the focal length of the lens on the light beam collimating means side. Lamp device. 2. The variable diffusion angle type lamp device according to claim 1, wherein the cylindrical lens step formed by the two lenses is a convex lens step and a convex lens step, or a combination of a convex lens step and a concave lens step. .