Illumination – Supported by vehicle structure – Plural light sources
Reexamination Certificate
2000-03-06
2001-10-09
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Plural light sources
C362S259000
Reexamination Certificate
active
06299337
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to a flexible multiple LED module which can be installed, in particular, in a luminaire housing, as can be used for example in exterior luminaires of motor vehicles.
Light-emitting diodes (LEDs) are increasingly being used in exterior and interior motor vehicle lighting systems, in particular for rear lights or brake lights, instead of the conventional incandescent lamps. LEDs have a longer service life as compared to incandescent lamps, better efficiency in the conversion of electrical energy into radiant energy in the visible spectral range, and, associated therewith, less emission of heat and overall a smaller space requirement. In construction, however, extra expenditure is necessary in the first instance, because, on account of the low luminance of a single LED compared with an incandescent lamp, it is necessary to construct a plurality of LEDs formed into an array.
A number of proposals have been disclosed heretofore for the realization of an LED array. For example, U.S. Pat. No. 5,404,282 describes an LED module in which a number of LEDs are fixedly mounted between two parallel, electrically conductive bars. That configuration is relatively efficient from a circuitry point of view, but is otherwise relatively inflexible for installation in a luminaire housing, i.e., a light assembly housing, since it cannot be adapted in a simple manner to curved housing forms (see FIG. 1 of U.S. Pat. No. 5,404,282).
U.S. Pat. No. 5,519,596 describes an LED module constructed from a metallic frame having rigid sections. LEDs are contact-connected between electrically conductive webs, and flexible sections, which are inserted between the rigid sections and are each constructed from a metallic, comb-like and bendable structure. Although that configuration yields the desired flexibility, by the same token it entails disadvantages. On the one hand, owing to the fact that the entire frame is produced from metal, the production of the flexible sections is excessively elaborate and difficult and, on the other hand, the circuit design in each case allows only the arrangement of one row of LEDs in a module section.
SUMMARY OF THE INVENTION
The object of the invention is to provide a flexible multiple LED module, in particular for a luminaire housing of a motor vehicle, which overcomes the above-noted deficiencies and disadvantages of the prior art devices and methods of this kind, and which, on the one hand, can be produced as simply as possible and, on the other hand, allows a large number of LEDs to be arranged in the individual module sections.
With the above and other objects in view there is provided, in accordance with the invention, a flexible multiple LED module, comprising:
a flexible printed circuit board;
a plurality of rigid printed circuit boards having main surfaces connected to the flexible printed circuit board and with a spacing distance between one another; and
a plurality of LEDs mounted on the flexible circuit board in a region of the rigid printed circuit boards.
In other words, the flexible multiple LED module has a plurality of rigid printed circuit boards which are composed of aluminum, for example, and are each connected at one of their main surfaces to a flexible printed circuit board with a given spacing between them. The LEDs are mounted in the region of the rigid printed circuit boards on the flexible printed circuit board. The flexible circuit board is thus preferably sandwiched between the individual rigid boards and the LEDs.
In accordance with an added feature of- the invention, the flexible printed circuit board carries an electric circuit and the LEDs are integrated in the electric circuit applied on the flexible printed circuit board. The LEDs are preferably produced using surface-mount technology SMT and mounted directly on the flexible printed circuit board in the region in which the flexible printed circuit board is bonded on the rigid printed circuit boards. This has the advantage of providing for optimum heat dissipation from the LEDs.
An LED that is preferably used is described by Möllmer and Waitl in the article “SIEMENS SMT-TOPLED für die Oberflächenmontage” [SIEMENS SMT-TOPLED for Surface Mounting], printed in the periodical
Siemens Components
29 (1991), issue 4, p. 147 et seq. in connection with FIG.
1
.
That form of LED is extremely compact and allows the arrangement of a multiplicity of LEDs on the flexible printed circuit board.
In accordance with an additional feature of the invention, the electric circuit comprises resistors disposed on the flexible printed circuit board in a region of the spacing distance between the rigid printed circuit boards.
In accordance with a preferred embodiment, the rigid circuit boards are formed of aluminum.
In accordance with another feature of the invention, the flexible printed circuit board is composed of flexible plastic. The preferred plastics are polyester or polyimide, so that the flexible circuit board would be a polyester or polyimide film. In a preferred embodiment, the flexible printed circuit board is constructed from a plurality of layers of polyimide (flexboard). The use of so-called flexboards, which are known per se in the prior art, is particularly preferred. Such flexboards are described, for example, by H. Kober in the article “Flexibel verdrahten auf kleinstem Raum” [Flexible wiring in a most confined space] in the periodical
F & X,
issue May 1996 p. 356 et seq., where these flexboards are described as multilayer printed circuit boards constructed homogeneously from a plurality of polyimide support films.
It is furthermore preferred for resistors that are contained in the electric circuit to be applied in the region of the spacings between the rigid printed circuit boards on the flexible sections of the flexible printed circuit board. As a result, the resistors can be thermally decoupled to an extent.
The multiple LED module according to the invention is particularly suitable for installation in a luminaire housing for ambient lighting, in particular for a motor vehicle, for example for rear or brake lights. There is therefore provided, in accordance with the invention, a multiple LED module assembly, comprising:
a luminaire housing for a motor vehicle; and
a flexible multiple LED module mounted in the housing, the flexible multiple LED module including
a flexible printed circuit board;
a plurality of rigid printed circuit boards having main surfaces connected to the flexible printed circuit board and with a spacing distance between one another; and
a plurality of LEDs mounted on the flexible circuit board in a region of the rigid printed circuit boards.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a flexible multiple LED module, in particular for a luminaire housing of a motor vehicle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
REFERENCES:
patent: 4173035 (1979-10-01), Hoyt
patent: 5038255 (1991-08-01), Nishihashi et al.
patent: 5162696 (1992-11-01), Goodrich
patent: 5375044 (1994-12-01), Guritz
patent: 5404282 (1995-04-01), Klinke et al.
patent: 5477436 (1995-12-01), Bertling et al.
patent: 5519596 (1996-05-01), Woolverton
patent: 5673995 (1997-10-01), Segaud
patent: 5746497 (1998-05-01), Machida
patent: 5975715 (1999-11-01), Bauder
patent: 6045240 (2000-04-01), Hochstein
“Flexibel verdrahten auf kleinstem Raum”, Kober, Carl Hanser Verlag, München, 1996, pp. 356-359.
“Siemens SMT-Topled für die Oberflächenmontage”, Frank Möller et al., Siemens Components 29, 1991, vol. 4, pp. 147-149.
Bachl Bernhard
Waitl Gunter
Choi Jacob
Greenberg Laurence A.
Lerner Herbert L.
O'Shea Sandra
Osram Opto Semiconductors GmbH & Co. oHG
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