DE102006058079A1 - Illumination apparatus e.g. reading lamp, for use as reading light in aircraft, has light-guiding element axially displaceably arranged in such manner that free-radiation region is provided between light source and light input surface - Google Patents

Abstract

The apparatus has a light source (10) e.g. white light LED, and a light-guiding element (20) pivotable and/or tiltable about a pivoting/tilting point (28). The light-guiding element is provided with a light-guiding axis (22), a light input surface (23) and a light output surface (26). The light-guiding element is axially displaceably arranged in such a manner that a free-radiation region is provided between the light source and light input surface. The element is made of transparent plastic or from glass e.g. high-transparent borosilicate glass such as DURAN(RTM: borosilicate glass).

Description

The The invention relates to a lighting device comprising a light source preferably with at least one light emitting diode and a light guide for Has illumination of an object.

Known are mobile light sources from the dental field, where a light source, for example, an LED lighting unit, is firmly connected to a flexible or rigid optical fiber. Such light sources are u.a. for curing dental fillings used.

The WO 01/19280 A1 describes, for example, an irradiation apparatus which includes a light-emitting unit and a light-receiving unit having an entrance opening, the light-emitting unit comprising a plurality of light-emitting elements whose rays emitting in a light cone directly irradiate the entrance openings.

The US 2004/0043351 A1 describes a similar unit in which a lens element is provided for better focusing.

From the US 5290169 a similar unit is known in which, inter alia, a rigid optical waveguide is provided, which has a concave geometry as a light entry surface.

task the invention is to provide a lighting device, on the one hand compact and on the other hand a flexible Ensuring illumination of objects. To ensure a sufficiently high illuminance, powerful Be used light sources.

The The object of the invention is achieved by a lighting device which the entrance mentioned Features and / or the following features includes. These features also include preferred embodiments. In the following, the symbol has particular advantages of the described embodiment out.

In a preferred embodiment of the lighting device according to the invention, the light of a light source ( 10 ) in a light coupling surface ( 23 ) of a light-conducting element ( 20 ), which a Lichtleitachse ( 22 ), coupled and by means of the light guide element by a light output surface ( 26 ) directed to a surface to be illuminated.

Between the light source and the light coupling surface can be a free jet area exist, so that the light source optionally removed from the light input surface can be arranged, so that between both usually an air gap is located.

The light guide is about a pan-tilt point ( 28 ) pivotable and / or tiltable arranged so that a user of the lighting device can direct the light to those places where he wants a lighting. As a pivoting movement while the lateral pivoting is referred to, for example, a movement to the left or to the right or the other way round, and as tilting is called a pitching motion, ie a movement from top to bottom or vice versa.

By the deflection of the light originating from the light source by means of the light-guiding element makes it possible make the lighting device very compact. Would the Light source used directly for lighting would be particular when using powerful light sources in or on this also means for cooling the Light source necessary, which thus also in the immediate vicinity of the lighting place to install would. For LED reading lights known in particular from aircraft, this would mean that the lighting head, in which the LEDs are integrated, be correspondingly large would. However, the use of a light guide allows separation the exit location of the illuminating light from the light source itself, which close or directly to a, preferably passive, heat sink can be arranged.

The light guide associated swivel / tilt point ( 28 ) can preferably at the intersection of the light guide ( 22 ) and the light input surface ( 23 ), which brings with it advantages and a low dependence of the light losses on the pivoting / tilting angle of the Lichleitelements for the light coupling in terms of high light output.

Prefers the light guide is rotatably mounted about the Lichtleitachse. This allows the user both by tilting and by twisting in particular, direct the light to the places he wishes it to if the light guide obliquely emitted to a main portion of the light guide axis. This can be the Light guide have two legs, one longer and one shorter, which are connected but tilted relative to each other tilted are. That in the longer Leg, thus guided in the main portion of the light guide light is through the transition in the tilted arranged shorter Leg also in the tilted direction of the shorter leg directed.

The pan / tilt angle is preferably less than 40 °, preferably 30 °. The light control element ( 20 ) is about the light guide axis ( 22 ) rotatably mounted.

The light guide element ( 20 ) is preferably axially opposite the light source ( 10 ) slidably mounted, wherein the Lichtleitachse ( 22 ) of one leg ( 21 ) of the light-guiding element ( 20 ) or of the light-guiding element ( 20 ) with the beam axis ( 13 ) of the light source ( 10 ) lie on one another. This allows the lighting device ( 1 ) retracted and designed to save space, which brings security benefits for many applications. In the extended state of the free-jet area is the largest, while in the retracted state, a contact between the Lichtleiteinkoppelfläche and the light source can exist. In this latter case, the free-jet area no longer necessarily exists. In addition to this additional adjustment, the axial displaceability of the light guide has the advantage that the lighting device in the retracted state, even when used, can be made very compact and space-saving.

Particularly preferred is the Lichtleitachse ( 22 ) of the light-guiding element ( 20 ) or relative to the beam axis ( 13 ) of the light source ( 10 ) aligned coaxially with each other. As a result, the highest beam intensities of the transmitted light can be achieved.

The light guide element ( 20 ) More preferably consists of a transparent plastic material (for example PMMA or polycarbonate) or glass, for example of a highly transparent borosilicate glass (eg DURAN ^®.) The light guide ( 20 ) is constructed in a particularly preferred embodiment of several fibers, in particular of a transparent plastic or of glass fibers.

The light guide element ( 20 ) may be straight, ie it has only a single light guide axis ( 22 ) on.

The light guide element ( 20 ) can also be formed from flexible optical fibers, for example one or more glass fiber bundles or one or more bundles of plastic fibers.

Fiber rods are particularly preferably used from a glass having a N _A of about 0.5. With this numerical aperture acceptance angle of about 30 ° are possible, ie the pan / tilt angle can be a maximum of about 30 °, without the light output decreases to unacceptable levels.

The fiber rods are known to exist several optical fibers made of a core glass, each one of which surrounded by a glass shell, which is usually a having a smaller refractive index than the core glass.

Also are fiber rods usable, which consists of a plurality of optical fibers of a core glass are formed, which are not individually covered by a coat, but in which the coat envelops the entire fiber rod. Also mixed forms these two described embodiments can are preferably used.

In a further particularly preferred embodiment, in the lighting device according to the invention fiber rods are used as light-guiding element, which have an N _A of about 1. This is achieved by using special types of glass in the fiber rod and allows acceptance angles of about 90 °, which allows pan / tilt angles of up to almost 90 °.

Particular preference is given to using fiber rods with optical fibers with the cladding glasses enveloping the core in each case, wherein the fiber rod additionally has a jacket which encloses the rod with its lateral surfaces. This outer coat can be colorless, but also dyed for certain applications. When using the colorless outer shell this can additionally increase the light output, as this ensures that in addition from the optical fibers vagabonding light can be directed to the illumination. This sheath line can advantageously contribute to an increase in the acceptance angle for light-guiding elements, preferably in the case of light-guiding elements whose N _{A is} not equal to 1.

Becomes instead of a fiber rod one consisting of a part of light guide used, for example, a massive glass rod, this can for Homogenization of the light profile originating from the light source, in particular by multiple reflection on the walls of the Lichtleitelements a mixture of light can take place.

Instead of straight light-guiding elements, angled light-guiding elements can also be used with preference. In this case, the light guide ( 20 ) at least one bending area ( 27 ), in such a way that the light-conducting element ( 20 ) a thigh ( 21 ) with a light guide axis ( 22 ) and a light input surface ( 23 ) perpendicular to the light guide axis ( 22 ) is arranged, as well as another leg ( 24 ) with a light guide axis ( 25 ) and a light output surface ( 26 ), wherein the light guide axis ( 22 ) and light guide axis ( 25 ) form a bending or tilt angle relative to each other, which is between 0 ° and 90 °, preferably between 20 ° and 70 °. As a result, a flexible illumination of, for example Ablagetischen, working surfaces and allows the illumination cone ( 29 ) can be individually adapted to the respective needs.

Also Combinations of flexible and rigid elements are used as a light guide or light-guiding elements possible.

By the tilting of the light guide element can lead to reflections of the come from the light source emitted light at the light entry surface. The reflected light goes for the lighting is lost and so can the light output of the lighting device reduce. Therefore, the light entry surface of the light guide is preferred polished and / or anti-reflective. In a further preferred embodiment the housing, in which the light-guiding element and the light source are mounted, and / or at least a part of the housing between the light source and the light entry surface of the Light-guiding element, mirrored. Particularly preferably, the housing is the Illuminating device in the free-jet area mirrored.

The light guide element ( 20 ) preferably has a light output surface ( 26 ), which are opposite the light guide axis ( 22 ) of the light-guiding element ( 20 ) or with respect to the light guide axis ( 25 ) of one leg ( 24 ) of the light-guiding element forms an angle of not equal to 90 °, whereby a schrägeder radiation direction of the illumination cone is made possible.

Other Angle of the light output surface are Naturally also possible. All Angle between 10 ° and 110 ° are advantageous in the use of fiber optic components. The diameter of a fiber optic light guide is particularly preferably between 5 and 8 mm. Larger diameters are depending on Application also possible provided for the corresponding application made less demands on the compactness become. For corresponding applications are of course also smaller diameters realizable.

Particularly preferred as the light source ( 10 ) uses one or a plurality of white light LEDs.

The light output surface ( 26 ) is preferably polished or slightly frosted, with a frosted surface for more uniform illumination and a polished surface for spot lighting is more advantageous.

The light input surface ( 23 ) may be flat, convex or concave, wherein when the surface is polished and preferably antireflective is a smaller angle dependence with respect to the light coupling, especially in concave geometry exists.

In a further preferred embodiment the light element has side emitting properties. This means, it can light on its sidewalls couple out. This can be achieved, inter alia, that the outer wall of the Roughened light guide and / or provided with scattering centers can, so that light is substantially perpendicular to the light guide axis can be disconnected.

The light source ( 10 ) preferably has a focusing element ( 12 ), with their light rays on a focus area ( 14 ) are focusable. Preferably, the focus area ( 14 ) in the light input surface ( 23 ) of the light-guiding element ( 20 ) or if the light input surface of the light guide is convex or concave in a real or virtual, defined by the light input surface relative to the light guide axis focal point. As a result, a very effective light coupling can be realized.

The board ( 15 ) of the light source particularly preferably has a control electronics ( 16 ) for the light-emitting diode ( 11 ), which, for example, keeps the current constant, which provides a compact design, at the same time an overload protection of the LED and permanently uniform brightness.

Additionally, on the board ( 15 ) is still provided electronics, with which the light source ( 10 ) can be dimmed continuously or in steps, whereby the power consumption can be reduced, for example, in the idle state, furthermore, the illuminance can be adapted to the wishes of the user).

The board ( 15 ) preferably also has a switch ( 17 ), for example in the form of a microswitch, with which the light source ( 10 ) can be switched on / off and / or dimmed in one or more stages.

In Connection with three-color RGB LEDs is also a color change feasible.

When using white light LEDs, it is known that the LEDs also have a more or less different color temperature due to their production. Therefore, either electronic circuits are used to achieve a certain color temperature, or LEDs are selected from a so-called bin, which then have a fairly similar color temperature. By the appropriate choice of materials (eg glasses) of the light guide having appropriate spectral transmission profiles, an adjustment of the color temperature of the LEDs is possible Lich. The glass acts specifically as a color filter. If, for example, a glass rod with properties homogenizing the beam profile is used as the light guide, which causes the transmitted light to heat up in transmission, a cluster of white light LEDs can be used as the light source, which usually has too cold a color temperature, and the lighting location nevertheless becomes reached a neutral color temperature.

The heat sink ( 40 ) may be part of a housing attachment for the lighting device ( 1 ) be. If the lighting device is integrated into a seat, for example, a thermally conductive frame of the seat, which is usually present anyway, can serve as a passive heat sink and thus make active cooling of the light sources or large passive heat sinks superfluous, cooling being understood as passive cooling, which does not require fans or Peltier elements or other energy consuming elements. This contributes to the compactness and low noise of the lighting device.

The light guide element ( 20 ) of the lighting device ( 1 ) preferably in the switched-off state of the light source ( 10 ) a rest position and when switched on a working position along the beam axis ( 13 ) of the light source ( 10 ), whereby the integration in a push-push housing is advantageously possible.

The ratio of the surface of the light coupling surface ( 23 ) to the surface of the light output surface ( 26 ) of the light-guiding element ( 20 ) can not be equal to 1, whereby an adjustment of the numerical aperture of the light-guiding element ( 20 ) to the radiation characteristic of the light source ( 10 ).

The light output surface ( 26 ) may have any contour, wherein the light input surface ( 23 ) is preferably circular.

The following uses are advantageously possible inter alia with the lighting device:
Use of the illumination device ( 1 ) as a seat lighting, as a reading light for aircraft seats, for seats in rail vehicles and / or in motor vehicles, especially in cars or coaches, the compact design and high functionality is particularly attractive.

Use of the illumination device ( 1 ) as a work lamp, which can be integrated in ceilings or walls.

Use of the illumination device ( 1 ) in furniture, especially in kitchen furniture.

Use of the illumination device ( 1 ) as object lighting in showcases.

Use of the illumination device ( 1 ) as glare-free, possibly retractable instrument lighting in cars (eg in the cockpit, center console, overhead console, as a map reading lamp).

Use of the illumination device ( 1 ) as integrated microscope illumination, wherein the microscope stand as a heat sink ( 40 ) is usable.

For this Application is in particular the advantage of the illumination device according to the invention to bear that they are executed very compact can. As a result, in particular effect lighting in places are possible, the previously not be considered with appropriate lighting effects could. As the interior is now a major selling point especially for Aircraft represents, the lighting device according to the invention also significant economic advantages over previously known lighting devices on.

The Invention will be described below with reference to preferred embodiments in more detail and with reference to the accompanying drawings described.

in this connection demonstrate

1 the only schematically shown plan view of a lighting device according to the invention,

2 the lateral view of the in 1 shown illumination device according to the invention.

Detailed description preferred embodiments

In a first preferred embodiment of the invention, which in the 1 and 2 for the sake of clarity, the lighting device comprises a light source ( 10 ) and one at a pan-tilt point ( 28 ) pivotable and / or tiltable light guide ( 20 ), the at least one light guide axis ( 22 ) and at least one light input surface ( 23 ) and a light output surface ( 26 ) having.

As a light guide axis is that axis or direction of the light guide element ( 20 ), along which the main propagation direction of the guided light extends and which generally the axis of symmetry of the light-guiding element (FIG. 20 ) ent speaks.

The light guide element ( 20 ) is, preferably axially displaceable, arranged so that between the light source ( 10 ) and the light input surface ( 23 ) a free jet area ( 9 ) can exist.

The pan-tilt point ( 28 ) of the pivotally tiltable light-guiding element ( 20 ) lies at the intersection of the light guide axis ( 22 ) and the light input surface ( 23 ).

Furthermore, the light guide element ( 20 ) in addition to its pivotable tiltability about the light guide axis ( 22 ) rotatably mounted.

Of the Swing-tilt angle is in this preferred embodiment less than 40 °, preferably less than 30 °.

In the preferred embodiment of the illumination device described here, the light guide element ( 20 ) against the, light source ( 10 ) In addition to its pivoting and tilting axially displaceable, preferably parallel slidably mounted to the Lichtleitachse.

Preferably, the light guide axis ( 22 ) of the light-guiding element ( 20 ) in a further embodiment relative to the beam axis ( 13 ) of the light source ( 10 ) arranged coaxially, this means that the lateral offset between the light propagation direction of the light originating from the light source with the substantially highest light intensity and the light guide axis is as small as possible.

The light guide element ( 20 ) preferably consists of a transparent plastic or of glass, preferably of a highly transparent borosilicate glass and particularly preferably consists of DURAN ^® .

In an alternative embodiment, the light-guiding element ( 20 ) rigid and composed of several fibers of a transparent plastic or glass fibers. Here, the light guide ( 20 ) are constructed by rigidly interconnected or flexibly held optical fibers.

In yet another alternative embodiment, the light guide ( 20 ) rigid and designed as internally mirrored hollow body, for example as a columnar hollow body with a round, elliptical or polygonal cross-section.

The light guide element ( 20 ) can either be straight or alternatively with at least one kink or bending region (FIG. 27 ), wherein the light guide element ( 20 ) then a thigh ( 21 ) with a light guide axis ( 22 ) and a light-emitting surface ( 23 ) which is perpendicular or oblique to the light guide axis ( 22 ) is arranged, as well as another leg ( 24 ) with a light guide axis ( 25 ) and a light output surface ( 26 ), in which the light guide axis ( 22 ) and light guide axis ( 25 ) form an angle greater than or equal to 0 ° and less than or equal to 90 °.

In a further embodiment, the light guide ( 20 ) consist of a combination of flexible optical fibers and rigid elements.

The light output surface ( 26 ) can be polished or slightly frosted and have a flat, convex or concave shape.

The surface of the light input surface ( 23 ) is preferably polished and provided with an antireflection coating.

In a further embodiment, the light guide ( 20 ) have side-emitting characteristics to thereby provide adequate backlighting.

The light source ( 10 ), which is preferably a white-light LED or comprises a combination of red, blue and green LEDs, a focussing element ( 12 ), with which the light beams can be focused.

The light beams are preferably focused on a focal surface ( 14 ) focusable in the light input surface ( 23 ) of the light-guiding element ( 20 ) is arranged or if the light input surface of the light guide is convex or concave, in a real or virtual, defined by the light input surface relative to the light guide axis focal point.

When real or virtual focal point is understood as that place from which light rays come substantially parallel continue to propagate to the light guide axis of the light guide. When Essentially parallel will be deviations from the actual Direction of the light guide axis of up to 20 °, preferably up to 10 ° and most preferably viewed from up to 5 °.

By through the spectral profile of the absorption of the material of the light guide element ( 20 ), a targeted adjustment of the color temperature of the light emitted by the lighting device is also effected.

Preferably, the white light LED is on a circuit board ( 15 ), which a control electronics ( 16 ) for the light-emitting diode ( 11 ), which preferably keeps the current constant.

In an alternative embodiment, the Ansteue electronics ( 16 ) designed so that the white light LED or the LED's are dimmable steplessly or in stages with this.

For this purpose, in another embodiment, the board ( 15 ) a switch ( 17 ), with which the light source ( 10 ) can be switched on / off and / or dimmed in one or more stages.

The lighting device comprises a heat sink ( 40 ), which is part of at least one housing attachment for the lighting device.

With the thermal coupling ( 18 ) to the fixed heat sink ( 40 ) can be ensured that, for example, LEDs can be used with relatively high luminous efficacy. An active cooling of the light source ( 10 ) as well as the control electronics ( 16 ) is therefore not required in this embodiment.

In a further preferred embodiment, the light-guiding element ( 20 ) of the lighting device ( 1 ) in the off state of the light source ( 10 ) a rest position and a switched on state a working position, along the beam axis ( 13 ) of the light source ( 10 ) are offset axially relative to each other.

The ratio of the surface of the light coupling surface ( 23 ) to the surface of the light output surface ( 26 ) of the light-guiding element ( 20 ) is preferably not equal to 1, in particular around the numerical aperture of fibers of the light-conducting element ( 20 ) to adapt to the Abstrahlcharacteristik the light guide.

The light output surface ( 26 ) have a plurality of different contours whereas the light input surface ( 23 ) is circular.

The The illumination device described above is advantageous as seat lighting and / or reading light for aircraft seats and / or for seats usable in rail vehicles and / or in motor vehicles.

Also the use as a work lamp, which can be integrated in ceilings or walls is due to the compact design significant advantages. The same applies to the use of the lighting device in furniture, especially in kitchen furniture or also as object lighting in showcases.

Advantageous Furthermore, the use of the illumination device as glare-free, possibly retractable instrument lighting in cars, in particular also as effect lighting especially for airplanes.

use the lighting device according to at least one of the preceding claims as integrated microscope illumination.

The Lighting device according to the invention has the particular advantage that the compact is building and it still allows efficient light over a pivotable and / or tiltable light-guiding element, which in addition in the direction of the light source is displaceable, to guide to the place to be illuminated.

Due to the pivoting / tilting mounting of the light-guiding element ( 20 ) can be achieved a high degree of flexibility in terms of the illumination of objects. Overall, a particularly compact design is possible with this arrangement, which allows in particular a space-saving installation.

There the at least one light-emitting diode is mounted on a circuit board, which preferably fixed by means of a thermal coupling with a fixed heat sink can be connected to an active, even at high light output, Energy requiring cooling device be waived.

1

lighting device

9

Free jet area

10

light source

11

led

12

focusing

13

beam axis

14

focus area

15

circuit board

16

control electronics

17

switch

18

thermal coupling

20

light guide

21

leg

22

guiding axis

23

light injection

24

leg

25

guiding axis

26

light coupling

27

bending area

28

Swivel-tipping point

29

lighting cone

30

object

40

heat sink

Claims (34)

Lighting device with a light source ( 10 ) and one around a pan-tilt point ( 28 ) pivotable and / or tiltable light guide ( 20 ), the at least one light guide axis ( 22 ) and at least one light input surface ( 23 ) and a light output surface ( 26 ), wherein the Light guide element ( 20 ), preferably axially displaceable is arranged so that between the light source ( 10 ) and the light input surface ( 23 ) a free jet area ( 9 ) can exist. Lighting device according to claim 1, wherein the pan-tilt point ( 28 ) at the intersection of the light guide axis ( 22 ) and the light input surface ( 23 ) lies. Lighting device according to claim 1 or 2, wherein the light-guiding element ( 20 ) around the light guide axis ( 22 ) is rotatably mounted. Lighting device according to at least one of previous claims, wherein the pan-tilt angle less than 40 °, preferably less than 30 °. Lighting device according to at least one of the preceding claims, wherein the light-guiding element ( 20 ) with respect to the light source ( 10 ) Is mounted axially displaceable. Lighting device according to claim 5, wherein the light guide axis ( 22 ) of the light-guiding element ( 20 ) relative to the beam axis ( 13 ) of the light source ( 10 ) is arranged coaxially. Lighting device according to at least one of the preceding claims, wherein the light-guiding element ( 20 ) is made of a transparent plastic or of glass, preferably of a highly transparent borosilicate glass, particularly preferably of DURAN ^® . Lighting device according to at least one of the preceding claims, wherein the light-guiding element ( 20 ) is rigid and composed of several fibers of a transparent plastic or glass fibers. Lighting device according to at least one of the preceding claims, wherein the light-guiding element ( 20 ) is straight. Lighting device according to at least one of the preceding claims, wherein the light-guiding element ( 20 ) is formed by flexible optical fibers. Lighting device according to at least one of claims 1 to 9, wherein the light-guiding element ( 20 ) at least one bending area ( 27 ), which is designed such that the light-guiding element ( 20 ) a thigh ( 21 ) with a light guide axis ( 22 ) and a light input surface ( 23 ), which is perpendicular to the light guide ( 22 ) is arranged, as well as another leg ( 24 ) with a light guide axis ( 25 ) and a light output surface ( 26 ), wherein the light guide axis ( 22 ) and light guide axis ( 25 ) form an angle greater than or equal to 0 ° and less than or equal to 90 °. Lighting device according to at least one of the preceding claims, wherein the light-guiding element ( 20 ) is formed of a combination of flexible optical fibers and rigid elements. Lighting device according to at least one of the preceding claims, wherein the light output surface ( 26 ) is polished or slightly frosted. Lighting device according to at least one of the preceding claims, wherein the light input surface ( 23 ) is plan, convex or concave. Lighting device according to at least one of the preceding claims, wherein the surface of the light coupling surface ( 23 ) and / or provided with an antireflection coating. Lighting device according to at least one of the preceding claims, wherein the light-guiding element ( 20 ) has side emitting properties. Lighting device according to at least one of the preceding claims, wherein the light source ( 10 ) a focusing element ( 12 ), with which the light rays on a focus area ( 14 ) are focusable, the light input surface ( 23 ) of the light-guiding element ( 20 ) corresponds. Lighting device according to at least one of the preceding claims, wherein the spectral profile of the absorption of the material of the light guide element ( 20 ) a targeted adjustment of the color temperature of the light emitted by the lighting device is effected. Lighting device according to at least one of the preceding claims, wherein as light source ( 10 ) at least one white light LED is used. Lighting device according to at least one of the preceding claims, wherein the circuit board ( 15 ) the light source driving electronics ( 16 ) for the light-emitting diode ( 11 ), which preferably keeps the current constant. Lighting device according to at least one of the preceding claims, wherein the circuit board ( 15 ) has a circuit with which the light source ( 10 ) is infinitely dimmable or in stages. Lighting device according to at least one of the preceding claims, wherein the circuit board ( 15 ) a switch ( 17 ), with which the light source ( 10 ) can be switched on / off and / or dimmed in one or more stages. Lighting device according to at least one of the preceding claims, with a heat sink ( 40 ), which is part of a housing attachment for the lighting device. Lighting device according to at least one of the preceding claims, wherein the light-guiding element ( 20 ) of the lighting device ( 1 ) in the off state of the light source ( 10 ) has a rest position and in the switched-on state a working position which is along the beam axis ( 13 ) of the light source ( 10 ) is shifted. Lighting device according to at least one of the preceding claims, wherein the ratio of the area of the light coupling surface ( 23 ) to the surface of the light output surface ( 26 ) of the light-guiding element ( 20 ) is not equal to 1. Lighting device according to at least one of the preceding claims, wherein the light output surface ( 26 ) has any contour, wherein the light input surface ( 23 ) is circular. Light guide element, in particular for a lighting device according to one of the preceding claims, comprising a light guide axis ( 22 ) and at least one light input surface ( 23 ) and a light output surface ( 26 ). Use of the lighting device after at least one of the preceding claims as seat lighting and / or reading light for aircraft seats and / or for seats in rail vehicles and / or in motor vehicles. Use of the lighting device after at least one of the preceding claims as a work lamp, which can be integrated in ceilings or walls. Use of the lighting device after at least one of the preceding claims in furniture, especially in kitchen furniture. Use of the lighting device after at least one of the preceding claims as object lighting in showcases. Use of the lighting device after at least one of the preceding claims as glare-free, possibly retractable instrument lighting in cars. Use of the lighting device after at least one of the preceding claims as integrated microscope illumination. Use of the lighting device after at least one of the preceding claims as a lighting element in vehicles, in particular as effect lighting especially for Aircraft.