The invention relates to a lighting unit. Lighting units are known in many embodiments. Playing a part in the design of a lighting unit is on the one hand the efficiency, thus the amount of light per unit of energy, and in addition the practical benefit and appearance. The practical benefit relates inter alia to the light output, while in respect of appearance both the form of the lighting unit and the light image and colour (temperature) of the light are important.

The invention has for its object to provide an efficient lighting unit which has a high light output and allows a great measure of freedom in design. According to the invention, this is achieved by a lighting unit comprising a light source and a light conductor connected thereto, wherein a first outer end of the light conductor remote from the light source has a finish such that it forms a virtual light source corresponding to the light source. Two light points can thus be formed with only a single light source.

When a second outer end of the light conductor facing toward the light source has a similar finish as the first outer end thereof, two substantially identical light points are formed.

This is the case particularly when the first and second outer end of the light conductor are substantially the mirror image of each other.

A bright light point is obtained when the first and/or second outer end forms a concave lens.

For a maximum light output it is preferred for the concave lens to have a substantially semi-spherical inner surface.

A slightly diffuse light image is obtained when the concave lens is at least partially frosted. In order to concentrate the light exiting the light conductor the lighting unit is preferably provided with an optical closing element co-acting with the first outer end of the light conductor.

In a first embodiment of the lighting unit the optical closing element can be fastened to the first outer end of the light conductor and an element carrying the light source can be fastened to the second outer end of the light conductor. The light conductor, which can for instance take a cylindrical form, thus in fact forms the structural backbone of the lighting unit.

It is on the other hand possible to envisage the light conductor being received in an at least partially translucent or transparent sleeve, the optical closing element being fastened to one outer end of the sleeve and an element carrying the light source being fastened to an opposite outer end of the sleeve. The sleeve thus forms a structural element in which the light conductor is received.

When the optical closing element and the element carrying the light source also comprise an electrical contact, and the contacts are electrically connected to each other by a conductor, the lighting unit can be connected on either side to an electrical circuit whereby the light source is powered. In the case of a structurally self-supporting light conductor the electrical conductor can then extend through a through-hole in the light conductor.

In the case of a lighting unit with a light conductor received in the sleeve the electrical conductor can extend between the light conductor and the sleeve.

A recess can be formed particularly in a peripheral surface of the light conductor, in which recess the electrical conductor is received. A receiving space for the electrical conductor can thus be formed in structurally simple manner.

For an optimal lighting effect a peripheral surface of the light conductor can be at least partially translucent or transparent. In the case of a translucent peripheral surface the light conductor itself is hardly visible, and only the real light source and the virtual light source at the two outer ends of the light conductor can be seen.

The peripheral surface of the light conductor can be at least partially frosted, whereby the light conductor, which is therefore then translucent, itself also lights up between the light source and the virtual light source at the outer ends.

This can for instance be achieved when an inner surface of the recess is frosted.

The light source preferably comprises an LED. An LED has a low energy consumption and a high light output, and is moreover very compact. LEDs are available in various colours and at very low cost.

The invention also relates to a lighting assembly. Such a lighting assembly comprises according to the invention a number of lighting units of the type described above. Special lighting assemblies can be formed by combining lighting units as described above with each other.

In one variant the lighting units are connected in parallel between two electrical conductors. A string or ladder of mutually parallel lighting units is thus as it were formed, with which various forms can in turn be created.

The invention will now be elucidated on the basis of two embodiments, wherein reference is made to the accompanying drawing in which corresponding components are designated with reference numerals increased in each case by 100, and in which:

Fig. 1 is a perspective view of a first embodiment of the lighting unit according to the invention,

Fig. 2 is a side view of the lighting unit of Fig. 1 ,

Fig. 3 is a cross-sectional view along the line III-III in Fig. 2,

Fig. 4 is a perspective view of a second embodiment of the lighting unit according to the invention,

Fig. 5 is a side view of the outer ends of the lighting unit of Fig. 4,

Fig. 6 is a cross-section along the line VI-VI in Fig. 5,

Fig. 7 is a cross-section along the line VII-VII in Fig. 5, and Fig. 8 is a perspective view of a lighting assembly comprising a number of lighting units according to Fig. 1 or Fig. 4.

A lighting unit 1 comprises a light conductor 2 which is connected to a light source 3. Light conductor 2 is embodied here as a cylindrical body of transparent material, in the shown example acrylic (PMMA). Light conductor 2 has a first outer end 4 facing away from light source 3 and a second outer end 5 facing toward light source 3. First outer end 4 of light conductor 2 is finished such that this outer end forms a virtual light source 6 with an emission similar to that of the actual light source 3. In this example the second outer end 5 of light conductor 2 facing toward light source 3 has a similar finish and is even the mirror image of first outer end 4. Both the first and second outer end 4, 5 are provided with a respective concave lens 7, 8 with a semi-spherical inner surface. In the shown example these lenses 7, 8 are in addition frosted.

The lighting unit is provided at its first outer end with an optical closing element 9 in the form of a cap with internal screw thread 10. This optical closing element is fastened onto external screw thread 11 on first outer end 4 of light conductor 2.

An element 12 which carries light source 3 is fastened to second outer end 5 of light conductor 2. This element 12 which carries light source 3 likewise takes the form of a cap with internal screw thread 13 which engages on external screw thread 14 of light conductor 2. Light conductor 2 thus connects the optical closing element 9 and the element 12 carrying light source 3, and in this way forms a bearing construction part of lighting unit 1.

The two caps 9, 12 are provided with respective electrical contacts 15, 16. Each contact 15,

16 here takes the form of a screw which is fastened in a respective opening 17, 18 with internal screw thread. The two contacts 15, 16 are electrically connected to each other by means of a conductor 19, this extending through a through-hole 20 in light conductor 2 in the shown example. One outer end 21 of electrical conductor 19 is connected to contact 15, while the other outer end 22 of electrical conductor 19 is pressed against a printed circuit board 23 of light source 3 by a biasing member 24, here a compression spring situated in cap 12. Mounted on printed circuit board 23 is an LED 25 which forms the actual source of the light.

The operation of lighting unit 1 is as follows. Contacts 15, 16 of lighting unit 1 are connected to an electrical circuit (not shown here). An electric wire (not shown here) can for this purpose be clamped between the head of respective contact 15, 16 and respective associated cap 9, 12 on either side of lighting unit 1 by screwing in the contacts 15, 16. Caps 9, 12 are manufactured from electrically conductive material, for instance stainless steel, and biasing member 24 is also manufactured from a conductive material, here spring steel. When the electrical circuit is closed, LED 25 will emit light which enters the light conductor through concave lens 8 at second outer end 5 and is there transmitted as a substantially parallel beam of rays to concave lens 7 at first outer source 6, since the light will shine out of light conductor 2. The light image of virtual light source 6 is similar to that of the actual light source 3. A single light source 3 thus creates the image of a double light source 3, 6. This makes lighting unit 1 very efficient. The resulting double light image is moreover aesthetically attractive.

In a variant of lighting unit 101 light conductor 102a does not form the structural backbone of the lighting unit, as in the first exemplary embodiment. Light conductor 102a is here instead received in a transparent sleeve 102b. This transparent sleeve 102b is provided here with external screw thread 111 on its first outer end 104b and external screw thread 114 on its second outer end 105b. The optical closing element 109 with internal screw thread 110 is thus fastened onto sleeve 102b, as is the element 112 with internal screw thread 113 which carries light source 103.

In this embodiment light conductor 102a is once again provided at its first and second outer end 104a, 105a with concave lenses 107, 108. Light conductor 102a is further provided with a recess 120 which is formed in its peripheral surface 126. This recess 120 forms a receiving space for electrical conductor 119. Such a recess 120 is technically easier to realize than the thin through- hole 20 in the first exemplary embodiment.

The second embodiment is further constructed in structurally the same manner as the first embodiment. Here there are also two contacts 115, 116 which can be screwed into caps 109, 112 in order to fixedly clamp an electrical conductor and thus be able to close an electrical circuit. Printed circuit board 123 of light source 103 is here once again biased against electrical conductor 119 by means of a spring 124, so that a good contact is ensured under all circumstances. Light source 103 also once again comprises an LED 125 here.

In this embodiment the finish of a peripheral surface 126 of light conductor 102a can be chosen differently than that of a peripheral surface 127 of sleeve 102b. The outer surface 126 of light conductor 102a could for instance be frosted, whereby light conductor 102a will diffuse light over its whole length when light source 103 is activated. This diffuse light is emitted through sleeve 102b, which in this example need not have a frosted outer surface 127 itself, but can be clear. It is also possible for only the inner surface of recess 120 to be frosted, instead of the whole peripheral surface 126.

The diffuse light image of this embodiment thus differs from that of the clear or transparent light conductor 2 of the first exemplary embodiment. Light conductor 2 is there almost invisible between outer ends 4, 5 with the light source 3 and the virtual light source 6 formed by concave lens 7.

Lighting unit 1, 101 according to the invention can take a relatively compact form, and in the shown example has a diameter in the order of a centimetre and a length which can amount to in the order of several centimetres. A large number of lighting units 1, 101 can be combined into a lighting assembly 200. This can for instance be done by connecting a number of lighting units 1 , 101 in parallel between two conductors 201, 202 which are connected to a power supply 203 and thus form an electrical circuit 204. This way of attaching and connecting lighting units 1, 101 allows a great measure of freedom in design of a lighting assembly 200. Conductors 201, 202 can in principle take any random form. And although the lighting units 1, 101 which are connected in parallel have the same dimensions in the shown example so that conductors 201, 202 are mutually parallel, it is also possible to envisage applying lighting units of different lengths so that conductors 201, 202 converge or diverge.

The invention thus makes it possible with relatively simple components and at relatively low cost to form lighting units which can create two light points with a single light source. It is even possible to envisage more than two light points being created if the light is also cast outward in directed manner at a point between the two outer ends of the light conductor. The light conductor as a whole can in addition also form an additional diffuse line of light.

Although the invention is elucidated above on the basis of a number of embodiments, it will be apparent that this can be varied in many ways. Instead of a straight light conductor it is thus also possible to opt for a different form, for instance a curved form. Nor does the outer periphery of the light conductor or of the sleeve have to be cylindrical, and a polygon could also be chosen in order to achieve different light images. Materials other than stated here can in addition be used for the light conductor, the sleeve and the caps. And although the lighting unit is shown here with a light source on the basis of LED technology, other light sources can also be envisaged.

The scope of the invention is therefore defined solely by the following claims.