WO2005005195A1

WO2005005195A1 - A license plate lamp for motor vehicles

Info

Publication number: WO2005005195A1
Application number: PCT/SI2004/000018
Authority: WO
Inventors: Mihael Trcek; Ales Logar; Tomaz Logar
Original assignee: SATURNUS AVTOOPREMA DD
Current assignee: SATURNUS AVTOOPREMA DD
Priority date: 2003-07-10
Filing date: 2004-04-05
Publication date: 2005-01-20
Anticipated expiration: 2006-01-10
Also published as: SI21553A

Abstract

The purpose of the invention is to create at least essentially planar lightning device, which will be adapted for mounting adjacent to the periphery of each license plate. Such lamp should be as much as possible hidden and protected against weather influences and also mechanical damages, and at the same time it should meet the requirements concerning sufficiently illuminating of the whole surface of a license plate attached onto the rear portion of a motor vehicle. The lamp consists at least of a casing (1) and a bulb (2), wherein the said casing (1) is at least essentially planar and comprises attaching seats (12’, 12') and optionally appropriate holders (13', 13') for placing the bulb (2) in a desired position, and moreover also a divergent lens (11), which is arranged in the central portion thereof and is symmetric with respect to the central transversal plane (15) and consists of a plurality of ribs (111), which are at least essentially triangular in profile. At least one additional optical directing means (16', 16') is foreseen on the casing (1) quite adjacent to the belonging end portion of the lens (11).

Description

A LICENSE PLATE LAMP FOR MOTOR VEHICLES

The present invention relates to lightning equipment for motor vehicles, especially to mounting the lights into motor vehicles, and in particular to lamps for illuminating a license plate of a motor vehicle.

By this, the invention is based on a problem, how to realize at least essentially planar lightning device, which will be adapted for mounting adjacent to the periphery of each license plate, which will be as much as possible hidden and protected against weather influences and also mechanical damages, and which could moreover meet the requirements concerning sufficiently illuminating of the whole surface of a license plate attached onto the rear portion of a motor vehicle.

US 4,868,723 describes a car license plate lamp. Such lamp consists of a casing, in which the bulb is mounted. Behind the bulb - when observing towards the illuminated license plate - there is a divergent lens as a translucide portion of the said casing, and beyond the bulb there is a reflector. A certain portion of available light beams, which are generated by the said bulb, passes through the said lens, where the light beams are refracted in such a manner, that as mush as possible uniform illumination of the license plate is achieved. At the same time, the most of residual light beams are reflected by means of the reflector towards the said lens. Despite to such concept, which seems to be quite simple, achieving required optical characteristics is not so easy as it seems to be. As determined by relevant rules, at least a minimum illumination of any portion on the surface of the license plate has to be ensured, so that also the portions arranged at maximum distance from the lamp must be sufficiently illuminated. At the same time, the light rays, which are intended illuminating the surface of the license plate, are allowed to extend in a vertical direction, while in the horizontal direction i.e. parallel to the road, the lamp should be practically invisible. To this aim, the lens of this known lamp is essentially planar, but extends in an inclined direction with respect to the horizontal plane of the road or ground and also with respect to the vertical plane, in which the license plate is placed. In such a way is the internal portion of the said lens, which is faced towards the vehicle, arranged in a larger distance from the road as the external portion of the lens, which is faced away from the vehicle. In such a way, an inclined surface is available on the bottom side of the casing in the area of the said lens, which is at the one hand exposed to moisture and impurities during the use of a motor vehicle, especially in bad weather, while on the other hand it is practically inaccessible during washing the car and is therefore extremely non-comfortable for cleaning. In order to ensure a required illuminating the license plate at all, the lens is equipped on its internal surface with a plurality of spherical concave step-like cavities, which extend along at least approximately circular curvatures. Manufacturing of such lens is no doubt very complicated, and in addition, any deformations, which may occur either due to increasing temperature of the interior of the casing or also due to changing certain properties of materials after certain time, may lead to essential hindering of optical performances of such lens. In addition, the reflector, which has to be available within the casing, is a concave spherical surface, which needs to be firmly placed in a quite exactly determined position with respect to the bulb and the filament thereof, and also with respect to the lens. When assuming that the said internal surface is obtained by means of vaporization of appropriate materials, it is therefore obvious, that manufacturing of such lamp is connected with comprehensive and expensive manufacturing steps. In addition, each discrepancy in mutual correlations among the said elements may always result in essentially decreasing the lightning capacity and consequently in adequately worse illumination of the surface of the license plate.

Bearing in mind the requirements, which are determined on the basis of relevant rules, and taking into account both known attempts in course of distribution the light beams all over the license plate surface, i.e. either by means of a single lamp comprising a curved Fresnel lens or also by means of two lamps, US 5,067,057 proposes a lamp, which consists of several reflecting surfaces, which are parabolic and arranged on the circumference. All these parabolic surfaces have a common focus, which is in the practice extremely difficult to achieve. Even extremely small distortions may lead to drastically decreasing of illuminating of at least certain portions on the license plate surface. Accordingly, also in this case manufacturing of reflecting surfaces and consequently of such lamp is extremely complicated and expensive, so that such concept seems to be on a border-line with respect to quite practical point of view.

Still further, GB 2 314 151 A describes a license plate lamp, comprising at least essentially spherical casing, consisting of transparent material. The basic concept of such light results from the purpose of ensuring as much as possible uniform illumination of the complete surface of the license plate. The external surface of the said casing is smooth, while its internal surface comprises a stair-like surface, which forms a divergent lens, which serves for diverging light beams, which illuminate the portions of the surface of the license plate, which lie closest to the lamp. In such a way this portion is illuminated less as it would be without using the said lens. The said spherical casing as such forms a further lens, which enables appropriate distribution of light beams all over the residual surface portions of the license plate. However, such attempt requires using a bulb of relatively high power. Furthermore, a spherical concept of such lamp is ordinary undesired from quite practical reasons. The casing of such lamp is normally protruding outside from the car-body, to which the lamp is mounted. Consequently, the lamp is pretty exposed to impurities and difficult for washing. The light may also be covered e.g. by means of appropriate downwards protruding portion of a car-body, which may be e.g. a gripping portion of a trunk cover or similar, however such covering ordinary makes washing even much more difficult or e.g. leads to hindering accessibility in the case of replacing a bulb. In addition, such concept of the light requires a relatively large volume, which might otherwise be used for gripping the trunk cover or e.g. for mounting a lock or also for any other purpose.

The invention relates to a license plate lamp for motor vehicles, which consists at least of a casing and a bulb, wherein the said casing is at least essentially planar and comprises a divergent lens, which is arranged in the central portion thereof and is symmetric with respect to the central transversal plane and consists of a plurality of ribs, which are at least essentially triangular in profile. In addition, the said casing comprises appropriate attaching seats and optionally also appropriate holders for placing the bulb.

According to the invention, at least one additional optical directing means is foreseen on the casing adjacent to each belonging end portion of the lens. By this, such optical directing means consists of an inclined surface, which is arranged on the internal surface of the casing, as well as of an inclined surface, which is arranged on the external surface of the casing outside of the area of the lens. In the preferred embodiment each external inclined surface of each corresponding optical directing means is foreseen in the area of an elongated cavity, which is at least essentially triangular in profile and is arranged on the external surface of the casing outside of the area of the lens, in particularly quite adjacent to the said lens. By one of possible embodiments, two additional optical directing means are foreseen, and each of them is placed adjacent to the belonging one of the opposite ends of the lens, and the external inclined surfaces, which are arranged on the external surface of the casing, are turned one towards another or one away from another, extending thereby in directions, which are inclined under a desired angle with respect to the transversal plane of the casing.

The lens of the lamp according to the invention consists of a plurality of refracting elements, especially ribs, which are at least essentially triangular in profile and arranged adjacent each to other and symmetrically with respect to the central transversal plane of the casing. By the preferred embodiment, the ribs of the lens extend in a direction, which is inclined with respect to the central transversal plane of the casing.

Now the invention will be explained in more detail on the basis of the embodiment, which is shown in the attached drawing, wherein

Fig. 1 is a lamp, observed from outside;

Fig. 2 is a side view of quite schematically shown lamp; and

Fig. 3 is a lamp, observed from inside.

A lamp, which is intended for illuminating a license plate, in principle consists of at least essentially planar and transparent casing 1 as well as of a bulb 2, which is placed in appropriate position with respect to the said casing 1. The said casing 1 comprises appropriate attaching seats 12', 12", which are equipped with required passages 120', 120" in order to enable mounting thereof to each corresponding vehicle, and moreover also with any other desired elements, which are known to those skilled in the art. In this particular embodiment, the said casing 1 comprises corresponding holders 13', 13" for holding the bulb 2 in a desired position. In addition, the said casing includes a lens 11 in its central area, by which - at least in the area of the said lens 11 - the outward surface 14 of the casing 1 is planar and smooth.

The said lens 11 is created symmetrically with respect to the central transversal plane 15, through which extends a general axis of symmetry of the whole lamp, and is a divergent lens and consists of a plurality of directing elements of a triangular profile, in this particular case of ribs 111, which enable refraction and in such a way a desired directing of light beams 19', which are generated by the bulb 2, in desired directions. Since in this particular case the illuminated surface of a license plate is lying outside of the central plane 15 of the casing 1, the ribs 111 extend in an inclined direction i.e. under a desired angle with respect to the said plane 15. The light beams 19', which are refracted within the said lens 11, are illustrated in Fig. 2 by means of dotted lines.

In order to achieve refraction of light beams 19" also in a direction, which extends under a relatively large angle with respect to the said plane 15, i.e. almost rectangular (Fig. 2), appropriate optical directing means (16', 16") are foreseen quite adjacent to both end portions - when observed in the longitudinal direction of the lamp - of the said lens 11. Respective light beams 19", which are herewith refracted in a characteristic manner by means of the said optical directing means 16', 16", are in Fig. 2 illustrated by means of straight lines. Each optical directing means 16', 16" consists of an inclined surface 161', 161 " arranged on the internal surface 17 if the casing, as well as of an inclined surface 162', 162" arranged on the external surface 14 outside of the lens 11.

Each of the said external inclined surfaces 162', 162" may be obtained by means of appropriate cavity 18', 18", which is triangular in profile and arranged on the external surface of the casing outside of the lens 11, in particular quite in adjacency of the said lens 11. Whenever the light beams 19', 19" should extend in a desired plane, which is not in coincidence with the plane of the external surface 14 of the lamp casing 1, then at least the inclined surfaces 162', 162" on the external surface 14 of the casing are turned one towards another or one away from another, and therefore extend under a certain angle with respect to the transversal plane 15, by which in this particular embodiment according to Fig. 2 the said angle is equal on both inclined surfaces 162', 162". However, generally speaking, the angle needs not to be equal on both inclined surfaces 162', 162", and may be adapted separately for each inclined surface 162', 162", when e.g. a license plate needs to be positioned asymmetrically with respect to the central plane 15 of the lamp.

Consequently, the lamp according to the invention comprises an essentially planar casing 1 and may no doubt be mounted in a simple manner into each corresponding vehicle e.g. above the license table and quite adjacent to it by means of two screws, extending through the belonging passages 120', 120". By this, the lamp is merely hidden and is not exposed to the weather conditions. In addition, the lamp in its mounted state comprises no protruding elements, which might hinder access to the vehicle parts in its adjacency, but on the other hand the lamp is simple and may be comfortably accessed for the purposes of cleaning or also e.g. replacing the bulb 2. Thanks to the said additional optical directing means 16', 16" a sufficient refraction of the corresponding light beams 19', 19" is ensured, so that the license plate is sufficiently illuminated even in the corner areas adjacent to the border area, above/adjacent to which the lamp is placed. In addition, thanks to the said planar concept of the casing 1 and due to quite simple configuration of the lens 1 , especially of the ribs 111, manufacturing of such lamp is also essentially simplified when bearing in mind the previously known lamps of such kind.

Claims

PATENT CLAIMS

1. A license plate lamp for motor vehicles, consisting at least of a casing (1) and a bulb (2), wherein the said casing (1) is at least essentially planar and comprises attaching seats (12', 12") and optionally appropriate holders (13', 13") for placing the bulb (2) in a desired position, and moreover also a divergent lens (11), which is arranged in the central portion thereof and is symmetric with respect to the central transversal plane (15) and consists of a plurality of ribs (111), which are at least essentially triangular in profile, characterized in that, at least one additional optical directing means (16', 16") is foreseen on the casing (1) quite adjacent to each belonging end portion of the lens (11).

2. Lamp according to Claim 1, characterized in that, each corresponding optical directing means (16', 16") consists of an inclined surface (161', 161"), which is arranged on the internal surface (17) of the casing (1), as well as of an inclined surface (162', 162") arranged on the external surface (14) of the casing (1) outside of the area of the lens (11).

3. Lamp according to Claim 2, characterized in that each external inclined surface (162', 162") of each corresponding optical directing means (16, 16") is foreseen in the area of elongated cavity (18', 18"), which is at least essentially triangular in profile and arranged on the external surface of the casing (1) outside of the area of the lens (11), in particularly quite adjacent to the said lens (11).

4. Lamp according to one of the Claims 2 or 3, characterized in that two additional optical directing means (16', 16") are foreseen, each of them is placed quite adjacent to the belonging one of the opposite ends of the lens (11), and the external inclined surfaces (162', 162"), which are arranged on the external surface (14) of the casing (1), are directed one towards another or one away from another, extending thereby in directions, which are inclined under a desired angle with respect to the transversal plane (15) of the casing (1).

5. Lamp according to any of the preceding Claims, characterized in that, the lens (11) consists of a plurality of refracting elements, especially ribs (111), which are at least essentially triangular in profile and arranged adjacent each to other and symmetrically with respect to the central transversal plane (15) of the casing (1).

6. Lamp according to Claim 5, characterized in that, the ribs (111) of the lens (11) extend in a direction, which is inclined with respect to the central transversal plane (15) of the casing (1).