GB2267334A

GB2267334A - Signal lamp for motor vehicles

Info

Publication number: GB2267334A
Application number: GB9310508A
Authority: GB
Inventors: Erich Bork; Heico Von Broich; Detlef Decker; Ulrich Helfmeier; Franz-Gerhard Jost; Klaus Kohlenberg; Rainer Kuebel; Lothar Scharwald; Manfred Lohmeier; Stephan Schroeder; Wilhelm-Friedrich Wallmeier; Peter Schuermann
Original assignee: Hella KGaA Huek and Co
Current assignee: Hella GmbH and Co KGaA
Priority date: 1992-05-27
Filing date: 1993-05-21
Publication date: 1993-12-01
Anticipated expiration: 2013-05-21
Also published as: FR2691683A1; ES2051248R; GB9310508D0; ES2051248B1; DE4217512C1; GB2267334B; ES2051248A2; FR2691683B1

Description

2267334 SIGNAL LAMP FOR MOTOR VEHICLES This invention relates to an

elongate form signal lamp for motor vehicles.

German patent application DE 4003569 Al discloses a motor vehicle lamp which is extended in length but small in height. This lamp has a casing which can be fitted into the structure of a motor vehicle body, into a rear spoiler, or under a shield behind the rear window, or can be mounted on the vehicle body. The casing houses a printed circuit board on which a number of light-emitting diodes are arranged in a longitudinal row electrically bonded to the board. The casing also has a lens plate with respective lenses for the individual light-emitting diodes, each lens imaging the light from the light- emitting diode assigned to it.

A drawback of this known elongate form signal lamp is that precise imaging by the lenses of the lens plate cannot be assured, because, owing to the extended length of the unit and the associated material and manufacturing tolerances, it is impossible to keep the lenses and the light-emitting diodes precisely in register. Because the one-piece printed circuit board is fixed to the casing and the one-piece lens plate is also fixed to the casing, the imaging behaviour of the individual lenses depends on the manufacturing accuracy of the casing and not just on the manufacturing and assembly 2 tolerances of the printed circuit board and lens plate. This means that precise imaging is not obtained, so that light losses and undesired light scatter effects occur. These disadvantages cannot be overcome even by the use of high-cost low-shrinkage materials, or by bearing the cost of precision fitting of the lens plate to the printed circuit board upon assembly.

A further disadvantage which the known type of unit has been found to possess is that the openings provided in the casing for circulation of cooling air are so arranged that the air passes between the light-emitting diodes and the lens plate, and this can cause soiling of the light-em tting diodes and also of the lenses of the plate, in the long term again resulting in a reduction in the light intensity of the motor vehicle lamp.

It is an object of the invention to provide a motor vehicle signal lamp in which better positioning of the lightemitting diodes in relation to the lenses imaging the light from the diodes, and to the casing, is obtained without undue expense or complexity, notwithstanding the extended length of the lamp unit and the associated material and manufacturing tolerances.

According to the invention this is accomplished by making the lens plate and/or the printed circuit board in a plurality of parts and by providing the lens plate with connecting elements for fixing the printed circuit board to the lens plate.

It is advantageous to form the lens plate and/or 3 the printed circuit board in a number of parts because this affords a simple and inexpensive way of making it possible to ensure that the positioning of the light emitting diodes in register with the lenses on the lens plate imaging the light from the diodes is independent of the material and manufacturing tolerances of the elongated casing, thus minimizing light losses and making it possible to provide the precise imaging required.

It is particularly advantageous in this regard for the lens plate to have connecting elements for fixing the printed circuit board to the lens plate whereby the positioning of the printed circuit board is essentially independent of the casing, and the light- emitting diodes, which constitute an optical system with the lenses of the lens plate, can be located as accurately as possible with respect to those lenses.

Providing each individual part of the lens plate and/or of the printed circuit board with at least one fastening element for engagement with the casing which establishes the orientation of each part of the lens plate and/or of the printed circuit board with respect to the casing affords the advantage that, besides allowing the optical system consisting of the printed circuit board with light-emitting diodes and lens plate with lenses to be placed in precise register in a simple and inexpensive manner, the optical system can be precisely orientated in the casing without it being dependent on the material and manufacturing tolerances of the casing.

4 It has been found advantageous for the fastening element or elements to be located centrally on the underside and/or top of each individual part of the lens plate and/or printed circuit board, to ensure that each part of the lens plate and/or printed circuit board is centred in the casing, so that, especially if the optical system produces an essentially parallel beam, this beam has a precise orientation with respect to the position and arrangement of the casing, and therefore to the motor vehicle.

It has also been found advantageous for each individual part of the lens plate to be provided with additional fastening elements which establish the position of that part at right-angles to the longitudinal axis of the casing, as the optical system consisting of the printed circuit board with lightemitting diodes and lens plate with lenses then remains independent of the tolerances of the casing, and yet the position of the lens plate with respect to the casing is clearly established so that the required imaging properties are assured.

Providing the connecting elements in the form of clips, spaced apart, with catch elements, on opposite edges of the lens plate, with the printed circuit board insertable between the said clips so that its position is fixed, yields the advantage of a particularly stable arrangement of the optical system consisting of the printed circuit board and lens plate, and in addition provides a unit which may be easily and cheaply fabricated and assembled.

It is advantageous for the printed circuit board carrying the lightemitting diodes to be electrically connected to another printed circuit board, arranged parallel in the casing by the connecting elements, which carries electrical components to adjust the voltage for the light-emitting diodes, as this arrangement both increases the stability of the optical system and reduces the thermal loading of the printed circuit board carrying the light-emitting diodes. It has been found particularly advantageous in this regard for the additional printed circuit board to be made in one piece with the board carrying the diodes, which further increases the stability of the optical system consisting of the printed circuit board with light-emitting diodes and lens plate with lenses, without tolerances on the material or manufacture having any significant effect on the precision of the imaging of the optical system.

By making the printed circuit board and the additional printed circuit board as a onepiece basic printed circuit board which is then parted, by using bendable wire pieces to form the electrical connection between the printed circuit board and the additional printed circuit board, and by using noses or other projections formed in the parting of the basic printed circuit board as catch elements for engagement in holes in the connecting elements, the production of the signal lamp is particularly facilitated, and also the tolerances on 6 the connection of the lens plate to the printed circuit board and the additional printed circuit board are kept to a minimum, thus ensuring high imaging accuracy of the optical system.

When a casing with ventilation openings is used, it has been found advantageous to position the openings in the casing above and below the additional printed circuit board so that the cooling air passes only through the region between the printed circuit board and the additional printed circuit board and between the additional printed circuit board and the casing, thus affording optimum cooling of the thermally loaded printed circuit boards whilst reliably preventing soiling of the optical system.

It is advantageous for the casing to be provided with a closure plate with light-scattering means to close the casing, so that the signal lamp can be used on a motor vehicle in any fitting or mounting arrangement. The signal lamp can advantageously be used as a high-level brake light for motor vehicles, as, besides achieving a prominent and precise signalling effect, the use of the invention allows a particularly flat and elongated signal lamp to be produced.

An embodiment of the invention, given by way of example, is illustrated in the drawings and will now be described in detail. Similar or functionally equivalent components are given the same reference symbols in all the figures of the drawings. In these:

7 Fig. 1 is a partial plan view, in section, of a signal lamp according to the invention, Fig. 2 is a transverse section through the unit shown in Fig. 1, Fig. 3a is a front view of part of a lens plate of the lamp, Fig. 3b is a plan view of the lens plate in Fig.

3a Fig. 4 shows a printed circuit board arrangement, Fig. 5 is an overall view of a signal lamp according to the invention.

Fig. 1 shows a partial section, in plan, of a signal lamp according to the invention. The lamp in this embodiment has a casing G with a translucent closure plate A, which can be fitted in, or mounted on, a motor vehicle body (whose presence is merely suggested in the drawing) by means of fastenings BE. The casing G has an elongated form, with small height.

Within the casing G a lens plate 0, which is made in several parts in order to equalise tolerances, extends over almost the whole length of the casing. In the illustrated example, only the left-hand part of the lens plate 0 is visible in its entirety. This lens plate part is fixed to the casing G by means of fastening elements B, which are positioned centrally and are integrally formed on the lens plate 0 at top and bottom. The fastening elements B which are located externally on 8 each part of the lens plate 0, where they are likewise located at top and bottom in the embodiment described here, serve as guide elements, in order that the lens plate cannot shift transversely to the longitudinal direction of the signal lamp, and hence deviate from the axial direction of light emission from the lamp.

In the illustrated embodiment each part of the lens plate 0 has four connecting elements V, of which only the two lower ones can be seen in the partial section of Fig. 1, These connecting elements V are integral with their respective parts of the lens plate 0 and project rearwards. They are provided with holes, visible in Fig. 5, which are formed as catch elements.

A printed circuit board L is fixed to the lens plate parts by means of the connecting elements V. In the embodiment shown here, the printed circuit board L has lightemitting diodes E which are arranged in a row, and are electrically bonded to the printed circuit board L. The diodes E each emit a coneshaped light beam. The lens plate 0 has a number of lenses I (Fig. 3) corresponding to the number of lightemitting diodes E on the printed circuit board L. Thus, each light- emitt ng diode has its assigned lens which images the light from the diode E, preferably to form an essentially parallel beam. The distance and positioning of the printed circuit board L and its light- emitting diodes E with respect to the lens plate 0 are determined by the connecting elements V. The printed circuit board L with the light- emitting diodes E 9 and the lens plate 0 thus constitute an optical system which can have a high imaging accuracy.

In the illustrated embodiment the imaging accuracy and the independence of the optical system of the tolerances on the elongate casing G are further enhanced by the fact that the printed circuit board L is also made in several parts (in three parts in this instance). The printed circuit board L has the same part interval or module as the lens plate 0.

In order to fix the position of each individual part of the printed circuit board L in the casing G, each part has at least one centrally located fastening element, which in the embodiment shown here is inserted in a hole in the casing G which is in the form of a slot LL, which fixes the printed circuit board L in the longitudinal direction of the casing G while allowing freedom of movement in the transverse direction. Thus it is centred by the central fastening elements B in the same way as the lens plate 0. The distance between the lens plate 0 and the printed circuit board L is determined solely by the connecting elements V.

In the embodiment shown here, an additional printed circuit board P carrying electrical components (not shown here) eg. for adjusting the voltage on the light-emitting diodes E, is arranged parallel with the printed circuit board L divided into a number of parts. This additional printed circuit board is made in one piece, and is also fixed to the lens plate 0 by the connecting elements V thus stabilizing the unit and reducing the thermal loading on the light-emitting diodes E. The additional printed circuit board P has an electrical socket connector S projecting outwards through the easing G for connecting the signal lamp to the electrical supply system of the motor vehicle. The printed circuit board L is electrically connected to the additional printed circuit board P.

The casing G has ventilation openings F to allow air to circulate between the printed circuit board L and the additional printed circuit board P as well as in the space between the casing G and that additional printed circuit board. These alleviate the thermal loading in the signal lamp Fig. 2 shows a section through a side view of a signal lamp as shown in Fig. 1. This section shows the two-shell casing G formation consisting of an upper cover part and a lower base part, and the closure plate A used in this case (which may have a scattering lens, for example, not shown here) forms part of the casing. The casing G with the closure plate A (which may be unnecessary in other embodiments) is sealed from the vehicle body (whose presence is only suggested in the drawing) by means of a seal D. The casing G is fixed to the vehicle body by a fastening BE comprising a bolt C inserted into the casing G, a spacer H, a nut M, a first washer Ul, a second washer U2 and a compression spring R. Other forms of fastening BE may be used in other fitting situations.

As already described with reference to Fig. 1, the section in Fig. 2 shows the lens plate 0 inserted in the casing G and the spaced, rearwardly projecting connecting elements V, in the form of clips with catch elements. The printed circuit board L carrying the lightemitting diodes E is inserted in the connecting elements V and thus fixed to the lens plate 0.

The additional printed circuit board P is also fixed to the lens plate 0 by means of the connecting elements V. The printed circuit board L is electrically connected to the additional printed circuit board but this connection is not shown in Figs. 1 and 2.

Fig. 2 also shows the electrical socket connection S which is electrically connected to the additional printed circuit board P and projects rearwards from the casing G. In other embodiments, the signal lamp may be connected to the electrical supply system of the vehicle via a permanently installed cable.

Figs. 3a and 3b depict an individual part of the lens plate 0 in two different views. As described under Fig. 1, the lens plate 0 in this embodiment, like the printed circuit board L, is divided into three parts.

Each part of the lens plate 0 has nine lenses I, each of which has a convex face on the side facing the lightemitting diode E, as can be seen from Fig. 3b, and an unillustrated opposite face turned away from the diode which may be formed, eg. as a Fresnel lens.

12 Each of the three parts of the lens plate 0 shown here has two fastening elements B centrally located at top and bottom, which serve to locate this part of the lens plate 0 in the casing G of the signal lamp. The other fastening elements B in the outer region of this part of the lens plate 0, which engage in the casing G in the assembled condition, serve to orientate the lens plate 0 in the casing G without fixing it in the longitudinal direction.

In the illustrated embodiment each part of the lens plate 0 has four connecting elements V, two of which can be seen projecting rearwards at opposite ends of the lens plate 0 from the bottom edge of the lens plate 0. As can be seen from Fig. 3b, each connecting element V has two staggered holes Y which act as catch elements for connecting to the printed circuit board L and the additional printed circuit board P. The length and choice of fastening elements B engaging with the casing G ensure that the imaging behaviour of the lens plate 0 is as independent as possible of the tolerances of the elongate casing of the signal lamp.

As already indicated, the basic printed circuit board T shown in Fig. 4 includes the printed circuit board L and the additional printed circuit board P joined together as a single unit. This basic printed circuit board T can be produced in a multiple printed panel, affording a particularly simple and inexpensive method of manufacture. As can be seen from the drawings, the 13 additional printed circuit board P carries the electrical socket connector S and electrical components W which are mainly resistors for voltage adaptation. The additional printed circuit board P is electrically connected to the printed circuit board L carrying the light-emitting diodes E via flexible wire pieces K, and is mechanically joined to the printed circuit board L by bridges ST of circuit board material. When the bridges ST are snapped, projections or noses X are formed, like those which can be seen on the outer edges of the additional printed circuit board P and printed circuit board L. These noses X serve as catch elements for engagement in the holes Y in the connecting elements V of the lens plate 0. The arrangement shown makes the printed circuit board arrangement particularly easy and cheap to produce and assemble in the signal lamp. As can also be seen from Fig. 4, the printed circuit board L in the selected embodiment is divided into three parts to equalize tolerances.

In the overall view of the signal lamp in Fig. 5 the lamp casing G is closed with a translucent cover plate A which may be provided, eg., with light-scattering optical means. In other embodiments it is possible to dispense with the closure plate A. The casing G is shown in Fig. 5 to be connected to the motor vehicle body or component by the four fastenings BE in the form of bolts projecting from the casing G. Fig. 5 also shows further of the openings F which are in the cover part of the 14 casing G and in its base part to allow air to circulate in the casing G so that the heat produced by the operation of the light-emitting diodes E (not shown here) is reliably dissipated.

Although the division of the lens plate into three parts is not visible in Fig. 5, it can be seen from the top view that each of these parts of the lens plate is provided on its upper edge with three fastening elements B projecting through holes in the casing G. Only the central fastening element B secures and locates the lens plate to the casing G. Also visible in this view are the two upper connecting elements V of each part of the lens plate 0, each having two staggered holes Y into which the noses X formed on the printed circuit board L and the additional printed circuit board P engage to fix the printed circuit board L and the additional printed circuit board P to the lens plate 0.

In other configurations of the signal lamp, a different division of the lens plate 0 and/or printed circuit board L may be adopted.

Claims

1. Motor vehicle signal lamp having an elongate form, and comprising a casing in which a number of lightemitting diodes are arranged in at least one row, a lens plate having lenses for the respective diodes being arranged in the casing so that each lens images the light from the light-emitting diode assigned to it, said lightemitting diodes being arranged on a printed circuit board made in a plurality of parts, and the lens plate also being arranged in a plurality of parts, and said lens plate parts having connecting elements for interconnection with the printed circuit board parts.

2. Signal lamp according to claim 1, wherein each part of the lens plate and/or of the printed circuit board has at least one fastening element for engagement with the casing which establishes the orientation of its respective part relative to the casing.

3. Signal lamp according to claim 2, wherein at least one fastening element is located centrally on the lower and/or upper edge of each part of the lens plate and/or of the printed circuit board.

4. Signal lamp according to claim 2 or claim 3, wherein each part of the lens plate has additional fastening elements which establish the position of each 16 part of the lens plate at right-angles to the longitudinal axis of the casing.

5. Signal lamp according to any one of the preceding claims, wherein the connecting elements comprise of spaced clips, provided with catch elements, said clips being formed on opposite edges of the lens plate, with the printed circuit board insertable between the said clips to fix its position.

6. Signal lamp according to any one of the preceding claims, wherein the printed circuit board carrying the light- emitted diodes is electrically connected to an additional printed circuit board arranged in parallel with it in the casing by said connecting elements, said additional board carrying electrical components for adapting the voltage for the lightemitting diodes.

7. Signal lamp according to claim 6, wherein the two printed circuit boards are made in one piece.

8. Signal lamp according to claim 6 or claim 7, wherein the printed circuit board and the additional printed circuit board are made as a one-piece board which is then parted, bendable wire pieces being employed to connect said printed circuit boards electrically.

17

9. Signal lamp according to claim 8, wherein projections formed in the parting of said one-piece board are employed as catch elements for engagement in holes in the connecting elements.

10. Signal lamp according to any one of claims 6 to 9, wherein the casing has openings positioned above and below the additional printed circuit board allowing circulation of cooling air through the region between said two printed circuit boards and between the additional printed circuit board and the casing.

11. Signal lamp according to any one of the preceding claims, wherein the casing has a face which is closed by a closure plate provided with lightscattering optical means.

12. Signal lamp according to any one of the preceding claims, arranged as a high-level brake light for a motor vehicle.

13. Motor vehicle signal lamp which having an elongate form, and comprising a casing, a printed circuit board arranged in the casing, with a number of light emitting diodes arranged in at least one row on the printed circuit board and electrically bonded thereto, a lens plate having a number of lenses corresponding to the number of light-emitting diodes and being arranged in the 18 casing so that each lens images the light from a respective light-emitting diode, said lens plate and/or the printed circuit board being made in a plurality of parts and in the lens plate having connecting elements for fixing the printed circuit board to it.

14. Motor vehicle signal lamp constructed and arranged for use and operation substantially as described herein with reference to the accompanying drawings.