EP3914047A1 - Led diode strip for continuous lighting with long durability - Google Patents

Abstract

Lighting strip (1) with LED diodes (11) of length (L) greater than or equal to 25m, of average nominal voltage DC U _N, in particular greater than or equal to 100V, the strip comprising: - A supply bus at the nominal voltage U _N, extending along the strip, - a plurality of modules (100) succeeding one another along the strip, each module being supplied with voltage of the bus via the supply bus and comprising at least two rows (14, 15, 16) of LED diodes, the LED diodes comprising at least N LED diodes electrically connected in series between the terminals of the supply bus, the number N being chosen so that the LED diodes have an electrical power at least 30% less than their nominal power, better still less than or equal to 40% of their nominal power, even better less than or equal to 50%.

Description

Technical area

The present invention relates to LED lighting devices and more particularly to LED lighting strips.

Prior art

Long LED strips, typically up to 50m, are found on the market for lighting structures such as tunnels.

The LED diodes are electrically arranged in a single row extending along the strip, with LED diodes electrically connected in series by a semi-rectified voltage from a mains voltage of 230V AC (i.e. an equivalent of 200V DC average approximately after double-wave rectification). LED diodes are typically Model 2835 with 0.2W maximum power and 0.1W rated power. LED diodes are used at their nominal or even maximum power.

The main cause of degradation of LED diodes and therefore of the service life of LED tapes is heat, which has difficulty escaping from the silicone envelope of the tape and also tends to cloud the latter.

To extend the life of the ribbons, the applicant has thought of not using them continuously lit, or of reducing the supply voltage of the ribbon, among other solutions.

However, the first case requires the installation of another tape or emergency light, and the second decreases the intensity of the light.

Requirement CN 104613357 discloses a lighting device comprising an LED strip of great length having short series of LED modules, the series being connected in series or in parallel. This device comprises a main power supply connected to the series of LED modules via circuits making it possible to supply these series of LED modules in DC with constant voltages and currents.

Requirement GB 2 361 988 discloses a modular lighting system comprising coextruded emitting ribbons. These ribbons have printed circuits and diodes. The system also includes contact elements for electrically connecting printed circuits to a power bus.

Requirement CN 102954375 discloses a lighting device comprising a plurality of lighting modules connected in series by interconnection elements, wherein each interconnecting element comprises a base plate and a hollow part, and the last lighting module of the device lighting comprises interconnecting elements which have been cut along their transverse axes to form female connectors.

Requirement CN109185737 discloses a lighting device configured to decrease damage to the device in the event of a short circuit of the lighting units. The device comprises lighting modules connected in series, each lighting module comprising at least two lighting components connected in parallel and each lighting component comprising at least two lighting units, each of the latter possibly being one. LED or a combination of LEDs.

Disclosure of the invention

There is therefore a need for an LED lighting strip which has an increased lifespan, while providing satisfactory lighting.

Summary of the invention

• Un bus d'alimentation à la tension nominale U_N, s'étendant le long du ruban,
• une pluralité de modules se succédant le long du ruban, chaque module étant alimenté sous la tension du bus par le bus d'alimentation et comportant au moins deux rangées de diodes LED, les diodes LED comportant au moins N diodes LED reliées électriquement en série entre les bornes du bus d'alimentation, le nombre N étant choisi de telle sorte que les diodes LED aient une puissance électrique inférieure d'au moins 30% à leur puissance nominale, mieux inférieure ou égale à 40% de leur puissance nominale, encore mieux inférieure ou égale à 50%.

The invention aims to meet this need and it achieves it by means of an LED lighting strip of length greater than or equal to 25 m, of average nominal DC voltage U _N , in particular greater than or equal to 100 V, the strip comprising:

• A supply bus at nominal voltage U _N , extending along the strip,
• a plurality of modules following one another along the strip, each module being supplied under the voltage of the bus by the supply bus and comprising at least two rows of LED diodes, the LED diodes comprising at least N LED diodes electrically connected in series between the power bus terminals, the number N being chosen so that the LED diodes have an electrical power at least 30% lower than their nominal power, better still less than or equal to 40% of their nominal power, even better less than or equal to 50%.

N can be between 15 ^∗ 3 ^∗ U _N / 200 and 30 ^∗ 3 ^∗ U _N / 200.

We can have U _N = 200 V + / - 5V, for example, but the invention is not limited to a particular voltage, and we can for example supply the tape with a filtered DC voltage, for example 24V or 48V or other, or rectified single-wave.

The ribbon according to the invention has an increased lifespan, because the LED diodes work well below their nominal power, and the heating level prevents degradation of the diodes and of the casing.

The less heating of the LED diodes makes it possible to arrange the LED diodes in two or three rows, or even more, to compensate for the lower light power emitted individually by each LED diode in the case of their nominal or even maximum use. The number of diodes per linear meter can thus be higher, and the light intensity be of the order of that of the previous ribbons.

The power supply can be done under a rectified or semi-rectified direct voltage, by means of a single or double alternation rectifier, supplied from the alternating network.

The input voltage of the rectifier can be that of the network, typically 230 V AC. It is thus possible to have the bus voltage U _N equal to practically 200V DC average (198V is measured with a voltmeter in DC mode).

As a variant, the module can be designed to operate at a nominal voltage U _N equal to approximately 100 V DC average, depending on the country, or even another voltage.

Each module preferably has three rows of LED diodes extending along the strip.

The ribbon preferably comprises a flexible printed circuit extending over its entire length, and carrying the LED diode modules.

Preferably, N is between 20 ^∗ 3 ^∗ U _N / 200 and 25 ^∗ 3 ^∗ U _N / 200.

The tape may be provided at its ends with connections linked to quick connectors, making it possible to connect several tapes electrically to one another and to ensure the electrical continuity of the supply bus between the tapes.

The tape typically comprises a flexible envelope of transparent plastic material, preferably a silicone.

Within the module, the LED diodes can be electrically connected by groups of six LED diodes, the groups being electrically connected to each other in series by means of electrical resistors, each group comprising two subgroups of three LED diodes connected electrically in parallel, the two sub-groups being electrically connected to each other in parallel.

The electric power per LED diode can be between 0.02 and 0.06W, better still between 0.03 and 0.04 W.

The electric power per LED diode can be at least half the nominal power, which is for example 0.1 W for a 2835 type diode.

The number of LED diodes per row and per linear meter of strip may be between 150 and 400, the number of LED diodes of the strip preferably being greater than or equal to 180 for 2 rows and 270 for 3 rows.

The light power per linear meter of tape can be between 400lm / m and 600lm / m for 2 rows and between 600 and 1100 lm / m for 3 rows.

The power supply bus may include copper conductors, in particular wire conductors, extending over the entire length of the tape and / or copper printed circuit tracks. The printed circuit can include a layer of copper 25 to 35 micrometers thick, against usually 10 to 20 micrometers, and the conductors of the cables a cross-section of stranded copper from 0.5 mm2 to 0.6 mm ² , against usually 0 , 3 to 0.4mm ² for known tapes.

The length of the tape may be greater than or equal to 50 m, in particular may be up to 100 m, or even 200 m.

Another subject of the invention is the use of a tape as defined above for lighting a structure such as a tunnel gallery, the tape being supplied 24 hours a day for at least 48 hours, in particular 7 days a week. / 7. A conventional ribbon will typically run from one to two weeks before some LED diodes fail, unlike the invention where the ribbon can run continuously for such a period of time without malfunction. a tape according to the invention is in particular designed to be able to operate for one or two years without interruption.

The structure thus lit is for example a gallery, in particular of width and / or height / diameter greater than or equal to 3 m.

The ribbon is advantageously supplied by the network via a half-wave rectifier bridge. The DC voltage at the output of this rectifier bridge corresponds to the voltage U _N. It is thus approximately 200 V DC for a power supply on the 230V AC 50Hz network.

Brief description of the drawings

• [Fig 1] la figure 1 représente de manière schématique et partielle, en perspective, un exemple de ruban selon l'invention,
• [Fig 2] la figure 2 est un schéma électrique du ruban,
• [Fig 3] la figure 3 représente de manière partielle et schématique le circuit imprimé, et
• [Fig 4] la figure 4 est une coupe transversale du ruban.

The invention may be better understood on reading the detailed description which follows, of an example of non-limiting implementation thereof, and on examining the appended drawing, in which:

• [ Fig 1 ] the figure 1 schematically and partially shows, in perspective, an example of a tape according to the invention,
• [ Fig 2 ] the figure 2 is an electrical diagram of the ribbon,
• [ Fig 3 ] the figure 3 partially and schematically represents the printed circuit, and
• [ Fig 4 ] the figure 4 is a cross section of the tape.

detailed description

There is shown in the figures a lighting strip 1 according to the invention, comprising a succession of modules 100 with LED diodes, these modules each being supplied by a supply bus at a nominal voltage U _N which is for example a current. Unfiltered DC generated by rectifying the 230 V AC, 50Hz alternating network with a diode bridge.

The length L of the tape is for example 50m or more, being able to reach 200m for example, according to the needs.

The tape 1 is equipped at its ends with connections 12 and 13 to quick-connect plugs (not shown), which ensure continuity of the supply bus and allow the ribbons to be electrically connected one after the other, the connection electrical being a parallel connection.

Each module 100 has, as can be seen on the figure 2 , LED diodes 11 which are electrically connected in series.

More precisely, the diodes 11 are grouped together by sub-groups 18 of three diodes directly connected in series, two sub-groups 18 being connected in parallel to form a group 110 of six diodes 11, the various groups 110 being connected together in series by resistors 17.

The number of groups 110 is 23 in the example considered, so that we have 3 ^∗ 23 = 69 diodes 11 in series between the + and - supply terminals, ie much more than in the prior art.

This higher number of diodes 11 supplied in series by the bus voltage reduces the voltage available at the terminals of each diode 11 and therefore the operating electrical power of each diode, which is thus for example more than 2 times less than the nominal power. at which each diode is intended to operate.

This results in less heating of the diodes 11, and a longer lifespan, even in the event of continuous operation 24/24 and 7/7.

The drop in the light power emitted by each diode 11 is compensated for by the greater number of diodes per linear meter of tape.

To achieve this, the diodes 11 are arranged in three rows 14, 15 and 16, extending along the strip, as visible on the figures 1 and 3 .

The diodes 11 are carried by a flexible printed circuit 20 and the diodes 11 of each subgroup 18 occupy the same axial position along the strip, as can be seen on the figure. figure 3 . This simplifies the parallel assembly of the diodes 11 within each group 110, and makes it possible to keep a relatively large conductive track width, and therefore to reduce the losses by Joule effect.

Each resistor 17 is arranged between two groups 110 and electrically connected to them by two respective tracks 112 and 113 in the general shape of a J lying to the right or to the left, which each extend along an edge of the circuit. printed, as visible on the figure 3 .

The diodes 11 are components mounted on the surface, for example of type 2835, of 0.2 W of maximum power and 0.1 W of nominal power.

In the example considered, the electric power per diode 11 is around 0.04 W, or approximately 11.7 W / m of tape, and the light intensity is of the order of 850 lm / m. The number of diodes 11 per m is for example 276 / m.

The printed circuit 20 is arranged in a flexible envelope 21 of which at least the portion covering the diodes 11 is transparent, as illustrated in figure 4 .

This envelope 21 is for example made of silicone. The slightest heating of the tape makes it possible to slow down the aging of the material constituting the envelope, in particular its yellowing in the case of silicone.

The width of the printed circuit is for example of the order of 15mm, for a total width of the tape of the order of 20mm. The copper thickness of the conductive tracks of the printed circuit 20 is preferably greater than or equal to 25 micrometers, being advantageously between 25 and 35 micrometers.

Of course, the invention is not limited to the example which has just been described. In particular, the ribbon can be produced with only two rows of LED diodes.

Claims (17)

Lighting strip (1) with LED diodes (11) of length (L) greater than or equal to 25m, of average nominal voltage DC U _N , in particular greater than or equal to 100V, the strip comprising: - A supply bus at nominal voltage U _N , extending along the strip, - a plurality of modules (100) succeeding one another along the strip, each module being supplied under bus voltage by the supply bus and comprising at least two rows (14, 15, 16) of LED diodes, the at least two rows of LED diodes comprising at least N LED diodes electrically connected in series between the terminals of the supply bus, the number N being chosen such that the LED diodes have an electric power at least 30% lower than their power nominal, better less than or equal to 50% of their nominal power, even better less than or equal to 40%. Tape according to claim 1, with N between 15 ^∗ 3 ^∗ U _N / 200 and 30 ^∗ 3 ^∗ U _N / 200 Tape according to claim 1 or 2, with U _N equal to 200V +/- 5V. Tape according to any one of the preceding claims, each module comprising three rows (14, 15, 16) of LED diodes extending along the tape. Tape according to any one of the preceding claims, comprising a flexible printed circuit (20) extending over the entire length of the tape, and carrying the LED diode modules. Tape according to any one of the preceding claims, with N between 20 ^∗ 3 ^∗ U _N / 200 and 25 ^∗ 3 ^∗ U _N / 200. Tape according to any one of the preceding claims, being provided at its ends with connections (12, 13) to quick connection plugs, making it possible to connect several tapes electrically to one another and to ensure the electrical continuity of the supply bus between the ribbons. Tape according to any one of the preceding claims, comprising a flexible envelope (21) of transparent plastic material, preferably a silicone. Ribbon according to any one of the preceding claims, within each module, the LED diodes being electrically connected in groups (110) of six LED diodes, the groups being electrically connected to each other in series by means of electric resistors (17 ), each group comprising two sub-groups (18) of three LED diodes (11) electrically connected in parallel, the two sub-groups (18) being electrically connected to each other in parallel. Strip according to any one of the preceding claims, the electric power per LED diode (11) being between 0.02 and 0.06W, better still between 0.03 and 0.04 W. Tape according to any one of the preceding claims, the nominal power of the LED diodes being 0.1 W per diode. Tape according to any one of the preceding claims, the number of LED diodes per row and per linear meter of tape being between 150 and 400. Tape according to any one of the preceding claims, the luminous power per linear meter of tape being between 400lm / m and 600lm / m for a two-row tape and between 600 and 1100 lm / m for a three-row tape of LED diodes. Tape according to any one of the preceding claims, the supply bus comprising copper conductors, in particular wire conductors extending over the entire length of the tape and / or copper printed circuit tracks, the printed circuit comprising a copper layer 25 to 35 micrometers thick. Tape according to any one of the preceding claims, its length (L) being greater than or equal to 50m. Use of a tape according to any one of the preceding claims for lighting a structure such as a tunnel gallery, the tape being supplied 24 hours a day for at least 48 hours, better still 7 days a week. Use according to Claim 16, to illuminate a gallery of width and / or height or diameter greater than or equal to 3 m.

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