JPH03222201A - Fog lamp front lens - Google Patents

Abstract

PURPOSE:To obtain a laterally extended light distribution pattern by partitioning a lens into two sections of a large slant angle part and a small slant angle part, and forming a wide diffusion light flux by the small slant angle part and a spot light flux by the large slant angle part. CONSTITUTION:A reflector 3 is supported on the rear part in the lamp chamber 4 of a lighting tool body 2 in such a manner as to be capable of tilting, and a front lens 1 is fixed to the front opening 2a of the lighting tool body 2. The front lens 1 is partitioned into a small slant section part 22 having a small slant angle on the upper side from nearly the center part and a large slant section part 23 having a large slant angle on the lower side. A wide diffusion area in which a number of cylindrical diffusion steps 25a-25d having short focal distances are transversely juxtaposed and a narrow diffusion area in which a number of cylindrical diffusion steps 25a-25d having long focal distances are transversely juxtaposed are formed in the small slant section part 22 and the large slant section part 23, respectively. Hence, a laterally extended distribution pattern can be obtained without reducing the whole light quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light distribution technology for a vehicle lamp, and more particularly to a front lens for a fog lamp having a slant angle.

[Conventional technology]

Conventionally, as shown in FIG. 7, a lighting bulb 5 is housed in a lamp body 51 to constitute a fog lamp 50, or is placed on a light axis of a reflector 52 and the reflector 52.
As the front lens 55 that covers the front surface of the lamp 3 and forms the lamp chamber 54, a lens generally used has a diffusion step 56 provided on its inner surface for the purpose of diffusing the light beam in the lateral direction.

However, in the case where the front lens 55 having such a diffusion step 56 has a slant angle θ inclined with respect to the optical axis, if the diffusion is increased, the irradiated light flux pattern P will be spread on both sides as shown in FIG. The problem was that it was distorted in the vertical direction. For this reason, when the front lens has such a slant angle, conventionally the front lens 55 does not have a diffusion step, but is positioned between the bulb 53 and the front lens 55 and is placed in the lamp chamber 54 perpendicular to the optical axis. In addition to arranging an inner lens 57 (see the two-dot chain line in FIG. 7), the inch lens 57 is provided with a diffusion step 58.

[Problem to be solved by the invention]

However, if the inner lens 57 is arranged inside the lamp chamber 54, not only will the depth of the lamp become larger, but also the aperture of the reflector 52 with respect to the front lens 55 will become smaller, reducing the irradiation efficiency and transmitting light through the inch lens 57. Therefore, there is a problem in that the illuminance attenuates and the amount of irradiated light decreases, making it difficult to use fog lamps with low brightness.

The present invention was devised in view of the above problem, and it is possible to obtain a light distribution pattern that is diffused in the width direction without reducing the overall light amount in a vehicle lamp having a slanted front lens. It is an object of the present invention to provide a front lens for a fog lamp that can constitute a high-intensity fog lamp, and to provide a fog lamp equipped with the front lens.

[Means to solve the problem]

In order to achieve the above object, a front lens for a fog lamp according to the present invention has a structure in which a front opening of a lamp body in which a bulb is arranged in front of a reflector is covered with a slant angle inclined to the optical axis. A small slant section with a small slant angle is formed on the upper side from the approximate center of the lens, and a large slant section with a large slant angle is formed on the lower side, and the small slant section has a large number of cylindrical diffusion steps with short focal lengths. The main point is to form a wide diffusion region in which the cylindrical diffusion steps with long focal lengths are arranged in parallel in the horizontal direction, and a narrow diffusion region in which a large number of cylindrical diffusion steps with long focal lengths are arranged in the large slant section in the horizontal direction. It is something.

Furthermore, the focal length of the diffusion steps in the small slant section and the large slant section, or one of the sections, is configured such that the focal length of the diffusion steps on both sides is longer than that of the parallel diffusion steps in the central part. It is preferable.

Further, the cylindrical diffusion step formed in the small slant section and the large slant section can be implemented by a convex lens or a concave lens-shaped diffusion prism.

[Effect]

In the above front lens, when the bulb is lit, the light beam that enters the diffusion step of the small slant section is diffused at a wide angle in the left and right direction due to the short focal point of each diffusion step.On the other hand, the light flux that enters the diffusion step of the large slant section Since the light beam has a long focal point, it becomes a spot irradiation with little diffusion in the left and right directions. Therefore, the irradiation pattern of the light beam that passed through the western part of both areas is such that the light beam that passed through the large slant section with a large slant angle illuminates the center, and the light beam that passed through the small slant section with a small slant angle illuminates both sides. As a result, distortion in the vertical direction of the side irradiation section is reduced, and a flat irradiation pattern that is diffused in the horizontal direction can be obtained.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a front lens for a fog lamp according to the present invention will be described below with reference to FIGS. 1 to 5.

1 and 2 show a fog lamp provided with a front lens 1 according to the present invention, in which a reflector 3 is supported in a tiltable manner at the rear of a lamp chamber 4 of a lamp body 2, and
The structure is such that the front lens 1 is fixedly installed in the front opening 2a of the lamp body 2.

That is, the reflector 3 has an inner surface formed as a parabolic reflecting mirror surface 5 having a focal point F on the optical axis, and a bulb holder 6 is fixed to the rear end of the reflector 3. A bulb 7 for the reflector 3 is attached so that its filament is located at the focal point F, and the reflector 3
It is advisable to adopt a structure in which the light is provided between the lamp bodies 2 or supported by a flap tilting adjustment mechanism. This reflector tilt adjustment mechanism consists of a pole joint 8 that has a ball shaft 8a integrally formed at its tip, and an adjustment rod 9 that is rotatably attached to the rear wall of the lamp body 2 but does not move in the axial direction. The ball shaft 8a of the pole joint 8, which is implanted and fixed on the inside of the rear wall of the lamp body 2, is fitted into a ball bearing 10 formed on the rear surface of the reflector 3 to form a rotation fulcrum part 1). A screw shaft portion 9a formed at the tip of the adjustment rod 9 is screwed into a self-nut 12 formed on the rear surface of the reflector 3 to form a distance adjustment portion 3 between the reflector 3 and the lamp body 2.

In this embodiment, the pivot point 1) is the reflector 3
The distance adjusting section 13 is arranged below the optical axis of the reflector 3, and above the optical axis, so that the tilting of the reflector 3 in the vertical direction can be freely adjusted and the optical axis can be adjusted.

In addition, an O-ring 14 is provided in the rear opening 2b of the lamp body 2.
It has a structure in which the cover 15 is hermetically fitted through the
One end of the cord 16 is connected to the bulb holder 6, and the other end of the cord 16 is led out of the lamp body 2 through a bushing 17 attached to the cover 15, and connected to vehicle body wiring (not shown) as appropriate. In addition, in this embodiment, the valve 7
The fog lamp constructed as described above has a structure in which a yellow globe 18 is placed over the outer periphery of the lamp body 2 to obtain a predetermined luminescent color.
It is inserted into the mounting hole B drilled in the hole B, and is attached and fixed by tightening the bolt 20 as appropriate.

The front lens 1 forms a downward slant with respect to the optical axis, and has a front opening 2 of the lamp body 2 at the rear end of the periphery.
In addition to forming a fitting edge 1a with the circumferential groove 21 formed on the edge of a, the lens surface has a slant angle θ from approximately the center to the upper side.
1 small small slant section 22, the lower side is slant angle θ
It is constructed of two surfaces consisting of two large slant sections 23. A large number of cylindrical convex lens-shaped diffusion prisms are arranged in parallel in the horizontal direction on the back surfaces of each of the small slant section 22 and the large slant section 23, and each of the diffusion prisms has a prism focal point as shown in FIG. The radius Ra, Rb of the sections 24a, 24b, 24c, 24d.

Diffusion steps 25a, 25b, 2 with different Rc and Rd
5C and 25d, and the radius value (tm) is specified as shown in Table 1 below.

The magnitude of the diffusion by the diffusion steps 25a, 25b, 25c, and 25d is determined by the radius Ra, Rh of the curved surface on the step side,
Due to Rc and Rd, diffusion step 7 25a, 25b,
If the focal lengths of the lenses 25c and 25d are shortened, the transmitted light beam will be more diffused.

As shown in Table 1 above, the small slant section 2
2 and the large slant section 23, the focal length of the diffusion steps 25a, 25b of the small slant section 22 is shorter than the focal length of the diffusion steps 25c, 25d of the large slant section 23. wide dispersion area” and “
forming a narrow diffusion region.

In each slant section 22.23, the focal lengths of the prism focal sections 24b and 24d at the center are shorter than the focal lengths of the prism focal sections 24a and 24C at both sides, and the central section A ``wide diffusion zone'' is formed on both sides, and a ``narrow diffusion zone'' is formed on both sides.

Further, 25e formed in the small slant section 22 is a prism stem located along the optical axis.

Incidentally, the above-mentioned diffusion prism has cylindrical convex lens-shaped diffusion steps 25a, 25b, and 25c.

Instead of the diffusing prism 25d, a diffusing prism including a cylindrical concave lens-shaped diffusing step may be configured.

In the fog lamp having the above configuration, since the bulb 7 is provided at the focal point F position of the parabolic reflecting mirror surface 5 of the reflector 3, the light beam reflected by the parabolic reflecting mirror surface 5 is emitted while being treated as a parallel light beam. Therefore, the diffusion step 25 of the small slant section 22
The light beam L1 incident on the large slant sections 25a and 25b is diffused at a wide angle in the horizontal direction due to its short focus, forming a wide irradiation pattern PI as shown in FIG. The light beam L2 incident on the light beam 25d has a long focal point, has little diffusion in the left-right direction, and forms a narrow irradiation pattern P2. In addition, in the light beam LL incident on the small slant section 22, the prism focal sections 2 on both sides
The structure is designed to suppress the diffusion of the light beam incident on 4a to a small extent. Therefore, as can be seen from the irradiation pattern, according to the irradiation of the fog lamp, the light beam L2 that has passed through the large slant section 23 with a large slant angle irradiates the central part and is transmitted through the small slant section 22 with a small slant angle. The structure that irradiates both sides with the light beam L1 generated by the light beam L1 is effective, and the distortion in the vertical direction of the side irradiation part can be reduced.
A flat irradiation pattern with suppressed curvature and spread in the horizontal direction is obtained.

〔Effect of the invention〕

Since the front lens for a fog lamp according to the present invention is constructed as described above, it is divided into three sections, a large slant angle part and a small slant angle part, and the large slant angle part forms a widely diffused luminous flux. By configuring the corner portion to form a spot light beam, distortion in the vertical direction on both sides of the light beam pattern is eliminated, and
It has features such as being able to configure a high-intensity fog lamp that can obtain a preferable light distribution pattern that is diffused in the width direction without reducing the overall light amount in a lamp having a slanted front lens, The effects after implementing the present invention are extremely significant.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a fog lamp showing an embodiment of the front lens for a fog lamp according to the present invention, and FIG.
-n line sectional view, Figure 3 is a front view of the front lens, Figures 4 and 5 are Figure 3 IV-IV line and V-V line sectional views, Figure 6 is an explanation showing the pattern of irradiation light. FIG. 7 is a vertical cross-sectional view showing the structure of a conventional fog lamp, and FIG. 8 is an explanatory diagram showing the pattern of the irradiated light. 24a. 24b-2 1...Front lens 3...Reflector 7...Bulb 22...Small slant section 23...Large slant section 4d...Prism focal section 25a. 25b-25d... Diffusion step 5 e... Prism step

Claims (4)

[Claims] (1) In a front lens having a structure that covers the front opening of a light fixture in which a bulb is arranged in front of a reflector with a slant angle inclined to the optical axis, a small slant section with a small slant angle is formed above the approximate center of the front lens. A wide diffusion area is formed in which the lower side is divided by a large slant division part with a large slant angle, and a large number of cylindrical diffusion steps with short focal lengths are arranged in parallel in the horizontal direction in the small slant division part,
The front lens for a fog lamp is characterized in that each of the large slant sections is formed with a narrow diffusion region in which a number of cylindrical diffusion steps each having a long focal length are arranged in parallel in the horizontal direction. (2) The focal length of the diffusion steps of the small slant section and/or the large slant section is configured such that the focal length of the diffusion steps on both sides is longer than that of the parallel diffusion steps in the center. The front lens for a fog lamp according to claim 1. (3) The front lens for a fog lamp according to claim 1 or 2, wherein the cylindrical diffusion step formed in the small slant section and the large slant section is a diffusion prism in the form of a convex lens or a concave lens. (4) A vehicle fog lamp comprising the front lens according to claim 1 or 2, wherein the reflector constitutes a parabolic reflecting mirror surface, and the filament of the bulb is located approximately at the focal point of the parabolic reflecting mirror surface. .