EP1341142B1 - LED illuminant - Google Patents

Abstract

An LED illumination having plates equipped with a number of LEDs with cables connecting the plates together and to a voltage source. A transparent encapsulation is provided for at least the LEDs on the plates. More specifically, one plate is provided per LED.

Description

The invention relates to an LED lighting according to the preamble of the main claim, in particular an LED lighting with a number of boards provided with light emitting diodes and at least one, the boards to each other and the voltage source connecting cable.

An illumination system, in particular for illuminating signs, inscriptions and letters with internal illumination, is already known from US Pat DE A1 100 52 380 known, which describes a low-voltage lighting system in which individual boards are brought with fasteners to the desired locations within the letters. Disadvantage of this system is the limited number of diodes, which can be connected in series, with a series resistor or an electronic circuit for keeping the current must be provided for each series circuit.

Furthermore, a variety of plugs must be protected against the ingress of water. This is expensive and costly, such as in the DE A1 199 04 915 shown pouring method under a profile-shaped cover shows. This creates a rigid, mechanically non-moving body, which then can hardly adapt to specific locations.

The invention, however, has set itself the task of creating an easy to install, universally applicable, rainproof, bright system that can be easily and quickly installed anywhere.

This is achieved by an LED lighting with the features of claim 1. The dependent claims give advantageous embodiments again.

It is advantageous in particular that a substantially transparent sheath advantageously covers a plurality of light emitting diodes on each of these individual boards in a transparent and substantially watertight manner. Thereby, e.g. 150 LEDs are combined in a tube. Any moisture that penetrates the ends can be evaporated again by the self-heating of the LEDs and escape. As insulation, e.g. a shrink tube absolutely sufficient.

Compared to previously known illuminations, the overall depth of bodies to be illuminated, e.g. Reduce letters of a neon sign because of the lower heat emission and the self-size of the lighting according to the invention; It can illuminate finer details and closer installation of multiple loops of the hose, the light intensity can easily and cheaply increase. The lighting is easy to install and the license requirements for over 1000-volt systems that have to be complied with in the past with neon-crystallisation are completely eliminated.

Since the light output of LED increases in colder temperatures, more light is emitted at night, but also in winter and even in bad weather.

The life is increased significantly, to 15-80,000 hours, which is not expected to complete failure but with slow decrease in brightness.

It is proposed to use as a coating hose, the diameter of which is greater than the diameter of the board, advantageously a shrink tube, which engages by heating, tight the board and thus loses its original round shape and thus a flat mounting surface on the back of the PCBs, opposite the LED offers.

In the tube, the individual boards are connected by a cable having an inner strand or a wire which is connected to the conductor paths on the boards. The sheathing of the line can also be made in one piece with the substantially transparent sheath of the light emitting diodes, so that it does not require a shrink tube, which is otherwise pulled over the possibly provided sheath of the line and in particular the boards together.

A repair is possible by replacing individual diodes, including the subsequent coating of shrink tubing on the repair site.

It is important that a non-circular LED lighting arises at least in the area of the boards, so that they can be fastened, for example via double-sided adhesive tape, the LED light is illuminated substantially perpendicular to the mounting surface. A certain amount of light at an angle to the side is quite desirable in the illumination of letters by internal LED lighting. This scattering effect can be due to embedded Diffused particles are reinforced in the transparent sheath or changed by colored particles or colorations in their color.

In particular, fluorescent components in the sheath have been found to be advantageous because they reduce the punctiform light character of the light-emitting diodes and produce a larger luminous area. At the same time, the color can be significantly influenced in this way.

Furthermore, it is proposed not to operate the diodes with low voltage in the range of 10 V to a maximum of 50 V, but with mains voltage of 220 V or even the maximum possible "low voltage" of 990 V. By rectification, a DC voltage of about 300 V or 990 V, so that up to 470 (red / yellow 2.1 V) or 275 blue / green / white diodes (3.6 V) can be accommodated in a diode tube. At 3 cm diode spacing, lengths of 14.1 m (red / yellow) and 8.25 m (blue / green / white) result.

The ballast should suitably have a power of 50W in the case of the rectified high voltage 990V and a constant diode current of, for example, 50mA. In the preferred embodiment for 220 V results in a correspondingly lower performance.

In case of failure (interruption of a single diode) not to put the entire series circuit out of action, each LED is a Z-diode connected in parallel. For this purpose, a Zener diode is arranged on the essentially rectangular printed circuit board next to the, for example, centrally arranged SMD diode (SMD = surface mounted device).

By always the same distance of the LEDs in the cable, a uniform distribution of the LEDs is facilitated, which are also cooled by board and cable.

There is no loss of heat due to series resistors or constant current circuits within the LED lighting. Since there are no series resistors, no power dissipation in the energy balance is to be considered. The rectifier losses that occur in the ballast are negligible.

Since the diode current is impressed by the ballast and is the same at every point, the same brightness prevails even if the hose is shortened. Optionally, the ballast can be manually dimmed to zero using a potentiometer or control.

For required bridge connections between two luminaires, the tube can be separated between two diodes. Through a connection cable, which is connected via a terminal, a simple connection to both hose ends of the other LED lighting hose.

Fig. 1

die erfindungsgemäße LED-Beleuchtung mit beispielhaft neun LEDs,

Fig. 2

eine Detaildarstellung einer LED-Platine sowie der angrenzenden Leitungsstücke,

Fig. 3

die LED-Platine ohne angrenzende Leitung in Draufsicht, und

Fig. 4

die LED-Platine der Fig. 2 im Schnitt durch Außenschlauch und befestigendes Klebeband.

Further advantages and features of the invention will become apparent from the following description of a preferred embodiment with reference to the accompanying drawings. Showing:

Fig. 1

the LED lighting according to the invention with by way of example nine LEDs,

Fig. 2

a detailed representation of an LED board and the adjacent line sections,

Fig. 3

the LED board without adjacent wire in top view, and

Fig. 4

the LED board of the Fig. 2 in section through outer tube and fixing tape.

The in the Fig. 1 illustrated, preferred embodiment with a pulled over the board shrink tubing consists of about 4 cm spaced LED boards, which are provided substantially at right angles, but with omitted outer corners in a tube which is arranged by way of example in a letter 'a' . The substantially upwardly emitting in a narrow beam LEDs are mounted on boards, which are surrounded by the transparent sheathing in the form of a sprayed cable jacket or in the form of a shrink tube or otherwise covered in a transparent manner.

In this transparent sheath, optically active particles or substances can be introduced in order to widen or color the light cone. Essentially, however, the light cone of the LEDs will suffice, with an accurate upward orientation not necessary, because due to the small distance to the next LED, the interior of a lighting fixture is illuminated anyway by a plurality of LEDs. As attachment of the hose, a double-sided adhesive tape, which can be mounted in particular on the back of the flat board sections of the hose, has proven itself. However, it is also conceivable, commercially available cable holder or the like to make the LED lighting easier to replace.

In the Fig. 3 are arranged on the board conductors 14, clearly visible. The interconnects 14 branch off from the interconnects to the LED diode to a Zener diode, which is connected in parallel with the LED diode. The Zener diode is arranged on one side of the LED diode on the board laterally next to the LED diode. On the opposite side, however, the board is sized just as large, in order not to obtain the straight arrangement disturbing the mounting, one-sided symmetry of the boards in the hose.

The boards are with a length of about 10 mm and a width of 5 mm from the z. B. 2 mm diameter cable with sheathing be much wider, so that the shrink tube, which engages tightly when heated, this leaves clearly visible as thickening in the diode tube. If necessary, an additional jacket can be sprayed onto the diode or heated into the hose, which may not yet be shrunk, before the heat-shrinkable tube has been heated.

In the Fig. 4 the geometric relationships are shown schematically in section.

In the case of the LED illumination according to the invention with a number of circuit boards 10 provided with light-emitting diodes 16, the distances of the circuit board from each other are at the cables connecting to a voltage source (see FIG Fig. 2 ) chosen so that at an angle between 90 and 150 ° large (preferably 115 to 125 °) in already 6 cm deep Lighting fixtures a uniform illumination of a windshield is possible.

If the width of a lighting fixture is greater than 4 cm (width of a leg to be illuminated in Fig. 1 ), it is proposed to lay the substantially transparent, tubular sheath 20 of the LEDs 16 on the boards 10 double row.

A slight inclination to the windshield, which illuminates the more inner wall of the luminous element, first equalizes the light distribution, only when parts of the windshield are no longer illuminated, should a rotation of the hose by attaching e.g. the hose fixing holders are reduced. Since a board 10 is provided for each light emitting diode 16, it is easy to ensure a flat alignment in the correct position.

The substantially watertight sheath 20 of the light-emitting diodes makes it possible to make the luminous element simpler, wherein the sheath 20 can cover more than one circuit board 10 and also the connecting paths between adjacent luminous bodies.

If, as suggested, the sheath is a shrink tube, the sheet character of the boards is maintained and subsequent seals are no problem.

Suitable material of the sheath 20 or incorporated fluorescent substances may cause novel color effects instead of or in addition to colored interior spaces to be illuminated.

Furthermore, a DC voltage supplying ballast with mains voltage can be integrated into the body to be illuminated, leaving enough space in front of and in addition to such a so-called converter in order to bring about uniform illumination.

An interconnection protection is ensured by Z-diodes 18, which are connected in anti-parallel to each LED. These are preferably as well as the cable 12, which is soldered with a wire or a strand 11 to a conductor 14 of the board, provided on this board.

As the shape of the board 10, a substantially rectangular, with its longitudinal extent corresponding to the extension of the cable connected to this board is selected, the corners are removed to form an elongated octagonal board.

Claims (10)

1. LED illuminant with a number of circuit boards (10) provided with light emitting diodes (16) and cables (12) connecting the circuit board with each other and with a voltage source, characterized by
   an essentially transparent covering hose as sheathing (20) at least of the light emitting diodes (16) on the circuit boards (10).
2. LED illuminant according to Claim 1, characterized in that one circuit board (10) is provided for each light emitting diode (16).
3. LED illuminant according to one of the preceding claims, characterized in that the sheathing (20) of the light emitting diodes is watertight.
4. LED illuminant according to one of the preceding claims, characterized in that the sheathing (20) covers more than one circuit board (10).
5. LED illuminant according to Claim 4, characterized in that the sheathing is heatshrink sleeving.
6. LED illuminant according to one of the preceding claims, characterized in that the material of the sheathing (20) has fluorescent substances.
7. LED illuminant according to one of the preceding claims, characterized by a ballast to which mains voltage is supplied and that outputs a direct current.
8. LED illuminant according to one of the preceding claims, characterized by a Z diode (18) that is connected anti-parallel to each LED.
9. LED illuminant according to one of the preceding claims, characterized in that the cable (12) has a wire or a braid (11) that is soldered to a conductor track (14) of the circuit board.
10. LED illuminant according to one of the preceding claims, characterized in that the circuit board (10) is connected essentially rectangularly with its longitudinal extent corresponding to the extent of the cable to the cable, the corners of the rectangle forming an elongate octagonal circuit board and no longer being present.

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