Patent Publication Number: US-2023146822-A1

Title: Lighting device

Description:
FIELD OF THE INVENTION 
     The invention relates to a lighting device. 
     TECHNICAL BACKGROUND 
     The invention can be useful in many application and/or assembly situations in the field of indoor lighting, for example, but also as outdoor lighting. In the following, we begin by explaining the invention and the underlying problem using the example of a built-in light. 
     Recessed lights, for example downlights emitting light from the ceiling, in particular into a room, are already commonly used in a wide variety of designs. Lighting devices which use magnetic forces for fastening or holding purposes have also already been proposed. 
     DE 10 2015 226 625 A1, for example, describes a lighting system with favourable anti-glare properties which offers the user a high degree of flexibility, wherein it is proposed that a light supply device could be attached inside a housing at different locations to the inner surface area of the housing using magnetic adhesion. This allows the light supply device to be positioned very freely within the housing. 
     A lighting device of this type involving the magnetic fastening of a light-generating unit means that the lighting direction can be adjusted in a very flexible yet discrete way. However, the adjusting procedure to position the lighting direction often includes at least two separate movements, namely the mechanical displacement of the light-generating unit, followed by the mechanical adjustment of the angular alignment in proportion to the changed position of the light-generating unit in relation to the exit opening. The adjustment of the light source is therefore very flexible yet at the same time relatively complex. 
     It would often be desirable to have a simpler setting option, wherein this should preferably also involve inconspicuous accommodation and/or protection of the light-generating unit. 
     SUMMARY OF THE INVENTION 
     Against this background, the invention is based on the object of creating a lighting device that enables the lighting direction to be adjusted more easily and quickly. 
     According to the invention, this object is achieved by a lighting device with the features of Patent Claim  1 . 
     A lighting device with a lamp housing and a lighting unit is proposed. In this case, the lamp housing is designed with a light emission area on the light output side thereof, and the lamp housing is furthermore designed with a curved, dome-shaped rear wall on a side thereof facing away from the light output side. In this case, the lighting unit is set up to emit light on the light output side thereof in order to emit the light through the light emission area of the lamp housing. Furthermore, the lighting unit has at least one device on the rear side of the lighting unit facing away from the light output side, which can be used to attach the lighting unit to a selectable point on the rear wall of the lamp housing using a magnetic force and thereby adjust the beam direction from the lighting unit in relation to the lamp housing. 
     The present invention is based on the finding that if the lighting unit is magnetically fastened to a curved, dome-shaped rear wall at a selectable point, it is possible to accommodate the lighting unit in the lamp housing with a simple structure, which, for example, can be used to create particularly discreet, hidden lighting and/or to protect the lighting unit, while at the same time using the dome-like curvature of the rear wall to align the lighting unit and thereby adjust or set the beam direction. Complicated mechanical mechanisms are not required. The rear wall can be used in a compact way for attachment and at the same time as a rear housing closure. The lighting unit can be fastened quickly and with little effort. The fully assembled lighting unit can be very easily connected to the lamp housing to form a functional light. 
     Favourable embodiments and developments of the invention are described in the additional dependent claims and the description with reference to the figures. 
     In a preferred embodiment, at least one device is attached to the rear side of the lighting unit and is designed as at least one magnet, in particular as at least one permanent magnet. An effective magnetic force effect can thereby be achieved in a simple, compact manner with little effort. 
     In particular, the beam direction of the lighting unit can be adjusted by moving the rear side of the lighting unit along the curved, dome-like rear wall of the lamp housing. For example, the achievable adjustment can be influenced by the curved shape design. Moving the rear side of the lighting unit along the rear wall allows for a variety of adjustment options. 
     According to one development, the adjustability of the beam direction includes adjustability of the beam angle of the lighting unit in relation to an axis of the lamp housing and/or adjustability by rotating the beam direction around the axis of the lamp housing. In this way, the beam direction can be adjusted in many different ways. The lighting device therefore offers great flexibility with regard to the achievable lighting direction. 
     In one embodiment, the curved, dome-shaped rear wall has an internal surface which is formed as part of a spherical surface. In particular, in further embodiments, the outer surface of the curved, dome-shaped rear wall can additionally be formed with part of a spherical surface. For example, in one embodiment, the curved, dome-shaped rear wall can also have a substantially uniform wall thickness. The selection of a spherical surface, in particular for the internal surface of the rear wall, contributes to a uniform adjustability of the beam direction when the lighting unit is moved along the rear wall, due to its constant curvature. For example, the rear wall can be designed as a spherical cap. 
     In particular, in one embodiment, the lighting unit is largely or completely positioned within the interior of the lamp housing. Accommodating the lighting unit in this way makes it possible to hide it in an aesthetic and unobtrusive way, in other words to accommodate it in such a way that it is not very visible to the viewer and does not attract attention. Furthermore, accommodating the lighting unit in this way facilitates good protection of the unit if required, for example when used outdoors to protect it from moisture and/or dirt. 
     In one embodiment, the lighting device is designed as a built-in lamp and/or the lamp housing is designed to be mounted in a recess or a cavity, in particular a recess or cavity in a ceiling or a ceiling component, a wall or a wall component, a floor or floor component or in an outer housing. This adds to the benefits of recessed and/or protected accommodation of the lighting unit. 
     In an development, the lamp housing is designed to essentially lie flush with a surface surrounding the mounted lamp housing when in an assembled state. Such accommodation of the lamp housing can, for example, have a restrained and aesthetic effect. The surface surrounding the mounted lamp housing could, for example, be the surface of a plate element, such as a false ceiling, wall or floor panel, or a surface around another type of recess in a ceiling, floor, wall or other element. 
     According to one embodiment, the lamp housing has one or more ball plungers to fasten the lamp housing. These can be used for the simplified, preferably detachable, attachment of the lamp housing at the installation site. 
     In a further embodiment, the lamp housing has one or more fastening devices for attaching the lamp housing in the recess of a plate element. This further simplifies the structure of the lighting device. The fastening devices can, for example, each have a tab element which is intended to engage behind the plate element near the edge of the recess. 
     In one embodiment, the beam direction of the lighting unit can be adjusted using a tool provided for this purpose. This makes it possible to use smaller versions of those elements of the lighting unit provided for the adjustment which are accessible to the operator for this purpose, and to completely avoid direct mechanical access by touching the elements, for example to improve the protective effect of the housing. 
     In one development, the tool is rod-shaped or tubular. This can make it easier, for example, to exert a suitable force on the lighting unit in order to adjust it. 
     In a further development, the tool has a continuous opening which allows light emitted by the lighting unit to exit through the continuous opening when adjusting the beam direction using the tool, which makes it possible for the operator to see the current beam direction of the lighting unit. 
     In one embodiment, the light emission area of the lamp housing is designed with a light emission opening accessible from a visible side when the lighting device is in the installed state. In particular, the tool is designed to temporarily engage, in particular within the coupling device, with a coupling device on the light output side of the lighting unit in order to adjust the beam direction, in particular with access via the light emission opening of the lamp housing. A reliable adjustment of the beam direction can thus be achieved from the visible side. 
     In one embodiment, the rear wall of the lamp housing is made from a ferromagnetic material, in particular steel. The lighting unit can thereby be easily, efficiently and conveniently attached using the magnetic force. 
     In a further development, the lamp housing has at least one access opening in a section thereof between the light output side and the curved, dome-shaped rear wall. In particular, the access opening is located in a lateral wall of the lamp housing. In particular, a wire for the electrical supply of the lighting unit, for example a cable, can be routed through the access opening, wherein the line connects the lighting unit to a control device located outside of the lamp housing. The lighting unit can thus be supplied with electrical energy for its operation in a simple manner and the lighting unit can be adjusted without hindrance. 
     In one embodiment, the lamp housing has a cover element which is formed with the light emission area and is positioned to cover an opening in the lamp housing on the light output side and which enables the lighting unit to be inserted into the lamp housing through the opening, wherein the cover element for covering the opening is magnetically attachable. This enables the lighting unit to be easily inserted and the cover element to be attached in a simple and reliable manner. 
     In one embodiment, the lighting device is intended for use indoors, in particular for installation in an interior area of a building. 
     In another embodiment, the lighting device is designed for outdoor use. 
     According to one embodiment, when the lighting device is in an operational state, the lighting unit is positioned completely within an internal space of the lamp housing, wherein the interior space is closed off from the outside and preferably sealed to prevent the ingress of water and/or dust from the outside. Such a lighting device is favourable for use outdoors, for example, where dirt and/or moisture are to be expected. 
     In a further development, the tool is designed with a counter-magnet which can be positioned on the external side of the curved, dome-shaped rear wall of the lamp housing and can preferably be moved on the outside. In this case, the counter-magnet attracts and interacts with the device on the rear side of the lighting unit, in particular with its magnet. This allows for easy adjustment of the beam direction while at the same time keeping the internal space of the lamp housing tightly sealed. When the counter-magnet is moved, this results in a corresponding movement on the rear side of the lighting unit in the internal space of the lamp housing. 
     In a further development, the rear wall of the lamp housing is made of a non-ferro-magnetic material, in particular a plastic or aluminium or an aluminium alloy. This can be favourable in order to achieve effective magnetic interaction between the device on the rear side of the lighting unit and the tool used for adjustment on the other side of the rear wall. 
     According to a further embodiment, the light emission area of the lamp housing has a light-transmitting cover that closes the lamp housing on the light output side. This achieves a protective effect with the simultaneous emission of light. 
     In yet another embodiment, a wire for an electrical supply to the lighting unit is led out from the internal space of the lamp housing through a sealed channel. This makes it possible to supply the lighting unit without impairing the sealing of the internal space, for example to protect it from moisture and/or dust. 
     An development proposes that the beam direction can be continuously adjusted or that the beam direction can be adjusted in predefined steps. In particular, it suggests that the beam angle can either be adjusted continuously or in predefined steps in relation to the axis of the lamp housing and/or the beam direction can be adjusted through continuous rotation around the axis of the lamp housing. Predefined steps can facilitate the precise adjustment of the beam direction, for example if the beam needs to be set at an identical angle to other lighting devices of the same type, for example with regard to the inclination relative to the housing axis. Continuous movement, on the other hand, increases flexibility when making adjustments. 
     In one embodiment, an element, in particular a ball, is attached to the rear side of the lighting unit and is spring-loaded towards the curved, dome-shaped rear wall in the internal side of the lamp housing. This type of element can create a latching effect due to the spring loading which can, for example, make it easier to adjust the beam gradually. A ball, for example, enables a simple transition from one step to the next and/or can simplify, for example, the continuous rotation of the beam direction around the axis of the lamp housing. 
     In a further embodiment, the curved, dome-shaped rear wall of the lamp housing in particular features concentric grooves on the internal side of the housing. For example, the spring-loaded element at the rear side of the lighting unit can engage with one of the selectable grooves, in particular in a latching and detachable manner, in order to implement predefined levels of the beam angle in relation to the axis of the lamp housing. In such an embodiment, the grooves enable the continuous rotation of the beam direction around the axis of the lamp housing. 
     In a further development, the lighting unit initially widens and then narrows in a longitudinal section of the unit from the light output side to the rear side of the lighting unit, wherein the area with the maximum radial dimension of the lighting unit is closer to the light output side than to the rear, or the lighting unit has a middle area with substantially constant maximum radial dimension aligned between the light output side and the back of the lighting unit. In this way, the lighting unit can be provided with a sufficiently large heat sink for effective heat dissipation while at the same time allowing for the adjustment of the lighting unit within a satisfactory angular range. 
     In particular, in one embodiment, the beam direction of the lighting unit can be inclined by an angle of up to approximately 30 degrees in relation to the axis of the lamp housing. However, other maximum tilt angles of inclination between the beam direction and the axis of the lamp housing are conceivable. 
     The embodiments and developments described above can be combined in any way where appropriate. Further possible embodiments, developments and implementations of the invention also include combinations of features of the invention described above or below with regard to the exemplary embodiments not explicitly mentioned. In particular, the person skilled in the art will also add individual aspects to the respective basic form of this invention as improvements or additions. 
    
    
     
       CONTENTS OF THE DRAWING 
       The invention is explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawings. The following are depicted: 
         FIG.  1    a central cross-section perspective view of a lighting device according to an initial exemplary embodiment; 
         FIG.  2    the lighting device in  FIG.  1    seen perspectively from a visible side; 
         FIG.  3    the lighting device in  FIG.  1    seen perspectively from the visible side, during the adjustment of the lighting unit; 
         FIG.  4    a lighting device according to a variant of the first exemplary embodiment, from the side, wherein a lighting unit is being adjusted for a main beam direction which is inclined by 20 degrees relative to the vertical; 
         FIG.  5    central cross-section of the lighting device in  FIG.  4   , wherein the lighting unit is being adjusted in the same way as in  FIG.  4   ; 
         FIG.  6    central cross-section of the lighting device in  FIG.  4   , wherein the lighting unit is being aligned for a main beam direction along the vertical; 
         FIG.  7    the lighting device in  FIG.  4    in a side view, during an adjustment of the lighting unit, with the main beam direction of emission aligned along the vertical; 
         FIG.  8    central cross-section of the lighting device in  FIG.  4    during the adjustment of the lighting unit, with the main beam direction inclined by −20 degrees relative to the vertical; 
         FIG.  9    cross-section of a lighting device according to a second exemplary embodiment, wherein a lighting unit is being adjusted for a main beam direction which is inclined by 30 degrees relative to the vertical; 
         FIG.  10    the lighting device in  FIG.  9    in a central section, the lighting unit being adjusted for a main emission direction which is inclined by 15 degrees relative to the vertical; 
         FIG.  11    the lighting device in  FIG.  9    in a central section, the lighting unit being adjusted for a main emission direction along the vertical; 
         FIG.  12    a top view XII of the lighting device according to the second exemplary embodiment of  FIG.  11   ; 
         FIG.  13    a bottom view XIII of the lighting device according to the second exemplary embodiment, see  FIG.  11   ; 
         FIG.  14    a perspective view of the lighting device according to the second exemplary embodiment, cut in the middle, in the state of  FIG.  11   ; 
         FIG.  15    a side view of the lighting device according to the second exemplary embodiment from the outside; 
         FIG.  16    a top view of the lighting device according to the second exemplary embodiment, wherein the lighting unit is aligned for an inclined main beam direction; 
         FIG.  17    central cross-section of a lighting device according to a variant of the second exemplary embodiment, in particular also to explain some tilt angles; 
         FIG.  18    a top view of an internal side of a rear dome-shaped housing wall of the lighting device according to the second exemplary embodiment and its variant; 
         FIG.  19    a perspective view of a lighting device according to a further variant of the first exemplary embodiment, with a lighting unit that is still outside of the lamp housing and a cover element that has not yet been attached to the lamp housing; and 
         FIG.  20    a sectional view of the assembled lighting device in  FIG.  19    with an inclined lighting unit. 
     
    
    
     The accompanying drawings are provided to clarify the embodiments of the invention. They illustrate the embodiments and, together with the description, serve to explain the principles and concepts of the invention. Other embodiments and many of the mentioned advantages will become apparent when consulting the drawings. The elements of the drawings are not necessarily shown at the same scale. 
     In the figures, elements, features and components which are identical and which have the same function and effect each have the same reference symbols, unless otherwise stated. 
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     A lighting device  1 ′ according to a first exemplary embodiment is illustrated in  FIGS.  1 - 3   . The device  1 ′ is a built-in “downlight” variant. The lighting device  1 ′ can be installed, for example, in a false ceiling in an internal space of a building, which is not shown here in its entirety, to illuminate the space.  FIG.  1    shows a plate element  25 ′ of such a false ceiling, which in this example mainly extends horizontally. 
     The lighting device  1 ′ has a lamp housing  2 ′ and a lighting unit  3 ′. The lamp housing  2 ′ has an internal space  12 ′, in which the lighting unit  3 ′ is positioned. The lighting unit  3 ′ is designed as a component which is independent from the lamp housing  2 ′ and can be moved relative to the lamp housing  2 ′. 
       FIG.  1    shows that the lamp housing  2 ′ in this exemplary embodiment is made up of a plurality of parts, with a front housing section seen from visible side S in  FIG.  1    designed with a circular, plate-shaped cover element  26 ′ and latched to a rear housing section. For this purpose, the plate-like cover element  26 ′ continues away from the visible side S in a cylindrical section. A visible front side of the cover element  26 ′ can preferably be painted over, for example in the desired colour of the ceiling. An outer circumference of the lamp housing  2 ′ can be of essentially circular design. 
     A section of the rear housing section on the rear side  11 ′ of the lamp housing  2 ′ is designed as a curved, dome-shaped rear wall  13 ′ made of steel as a ferromagnetic material. 
     An internal surface  15   a ′ of the rear wall  13 ′ on the internal side thereof is formed as part of a spherical surface. A curvature of the internal surface  15   a ′ is therefore the same at every point on the rear wall  13 ′ and is consequently constant. An outer surface of the rear wall  13 ′ on the external side  14 ′ thereof is also formed as part of a spherical surface, with the result that the wall thickness of the rear wall  13 ′ is essentially uniform. The rear wall  13 ′ of the device  1 ′ can be produced expediently, but a spherical segment-shaped outer surface of the rear wall  13 ′ is not absolutely necessary in the exemplary embodiment in  FIGS.  1 - 3   . 
     The internal space  12 ′ of the lamp housing  2 ′ shown in  FIG.  1    is therefore delimited by a flat front wall  26 ′, the essentially spherical cap-shaped rear wall  13 ′ and an essentially cylindrical section between the front wall  26 ′ and the rear wall  13 ′. 
     When the lighting device  1 ′ is mounted as shown in  FIGS.  1 - 3   , the lamp housing  2 ′ ends essentially flush with a surface  27 ′ of the plate element  25 ′ surrounding the lamp housing  2 ′.  FIG.  2    in particular shows the restrained, aesthetic and unobtrusive installation, in which the lighting unit  3 ′ is barely visible to a viewer in the illuminated space. 
     In  FIG.  1   , a central axis A 2 ′ of the lamp housing  2 ′ essentially runs along a vertical direction V and through a centre point of the cover element  26 ′, wherein the cover element  26 ′ forming the front housing wall and the rear wall  13 ′ are essentially rotationally symmetrical in relation to the axis A 2 ′. 
     The lamp housing  2 ′ is equipped on its circumference with several ball plungers  31 ′, each of which has a ball  32 ′ which is spring-loaded in the radial direction. In the first exemplary embodiment, four ball plungers  31 ′ are arranged on the periphery of the lamp housing  2 ′ at intervals of 90 degrees around the housing central axis A 2 ′, thus, enabling the lamp housing  2 ′ to be supported uniformly. 
     With the help of the ball plunger  31 ′, the lamp housing  2 ′ is mounted in a recess  29 ′ in the plate element  25 ′, for example an intermediate ceiling, in a simple and easily detachable manner. For this purpose, the balls  32 ′ of the ball plunger  31 ′ latch onto a suitable groove or behind a suitable offset in the recess  29 ′. 
     A frame-like assembly set  35 ′ can also be provided for the flush fastening of the lamp housing  2 ′ in the recess  29 ′, which can provide, for example, an offset or an edge to click the balls  32 ′ into place. 
     The lighting unit  3 ′, which can be moved in the internal space  12 ′, has a heat sink  18 ′ featuring a printed circuit board (“PCB”)  20   a ′ with an LED device  20   b ′ for light generation. The lighting unit  3 ′ also has a lens  21 ′ positioned in front of the LED device  20   b ′ in the direction of the light emission which is surrounded on the front, light-emitting side device by a funnel-like cover and beam-limiting element  22 ′ with a central tube extension  22   a ′. The heat sink  18 ′, the circuit board  20   a ′ with the LED device  20   b ′, the lens  21 ′ and the cover and beam-limiting element  22 ′ are arranged concentrically along a central axis A 3 ′ of the lighting unit  3 ′ in this order towards the light output side  17 ′ of the lighting unit, wherein the axis A 3 ′ also coincides with a central axis of the tube extension  22   a ′, which is equipped with a circular internal cross section. 
     This has a light emission area  7 ′ on the light output side  5 ′ of the lamp housing  2 ′. During operation, the lighting unit  3 ′ emits light on the light output side  17 ′ of the lighting unit  3 ′ through the tube extension  22   a ′, wherein the light emitted in this way is directed outwards through the light emission area  7 ′, i.e. into the room to be illuminated. For this purpose, the cover element  26 ′ has a central, preferably circular, light emission opening  8 ′, which enables the light emitted by the lighting unit  3 ′ to leave the unit.  FIGS.  1 - 3    show that the aperture  8 ′ is accessible from the visible side S when the lighting device  1 ′ is in the assembled state. 
     The lens  21 ′ is designed in such a way that the light generated by the LED device  20   b ′ passes through the relatively narrow inner channel of the tube extension  22   a ′ and the relatively small light emission opening  8 ′ to the outside on visible side S as a cone of light K with a relatively large cone opening angle, for example from between about 20 degrees and about 40 degrees. This contributes to the fact that the light source is not or barely visible to the viewer. In this case the lens  21 ′ is designed, for example, in such a way that the lens  21 ′ focuses the light entering it from the LED device  20   b ′ at a downstream location, thereby allowing a narrow exit opening  8 ′ to be used despite large distances. This avoids non-aesthetic visible points of light. 
     A diameter D 8 ′ of the light emission opening  8 ′ is relatively small compared to the surface area of the cover element  26 ′ and in some examples can be in a range from about 11 mm to about 15 mm, with D 8 ′ being about 12 mm or 13.5 mm or between and including 12 mm and 13.5 mm. 
     The curved, dome-shaped rear wall  13 ′ of the lamp housing  2 ′ is positioned on the rear side  11 ′ of the lamp housing  2 ′ facing away from the light output side  5 ′. In the lighting device  1 ′, the lighting unit  3 ′ is magnetically attached to the dome-like curved wall  13 ′ of the installation housing  2 ′ on the inside, wherein the exit beam angle or main beam direction A of the lighting unit  3 ′, for example along the central axis of the cone of light K, in relation to the lamp housing  2 ′, and thus the beam angle in the sense of an inclination of the main beam direction A relative to the axis A 2 ′ in a plane that contains the axis A 2 ′, as well as the beam angle in the sense of a rotation of the main beam direction A about the axis A 2 ′ in the circumferential direction, can be adjusted by moving the lighting unit  3 ′ along the dome-like rear wall  13 ′. 
     In order to attach the lighting unit  3 ′ to a selectable location on the rear wall  13 ′ using a magnetic force and to thereby enable the adjustment of the beam direction A, the rear side  19 ′ of the lighting unit  13 ′ facing away from the light output side  17 ′ of the lighting unit  13 ′ has a permanent magnet  23 ′ attached to the heat sink  18 ′, for example by means of a screw connection, which can interact with and adhere magnetically to the ferromagnetic rear wall  13 ′. The magnet  23 ′ is, for example, ring-shaped and is generally positioned concentrically to the heat sink  18 ′, the circuit board  20   a ′, the lens  21 ′ and the element  22 ′ on the rear side of the heat sink  18 ′. 
     To adjust the beam direction A, the rear side  19 ′ of the lighting unit  3 ′ is moved and displaced along the curved rear wall  13 ′ with the aid of an adjustment tool  97 ′, which has an elongated tubular design. One end of the tool  97 ′ may be snugly inserted into the interior channel of the tube extension  22   a ′ to make adjustments. The tube extension  22   a ′ therefore serves not only as a light outlet, but also as a coupling device  37 ′ on the light output side  17 ′ for the temporary engagement of the tool  97 ′ during the adjustment process. In this way, the elongated tool  97 ′ is inserted on the visible side S into the aperture  8 ′ to enable the continuous adjustment of the beam direction A, and therefore the beam angle. In the exemplary embodiment shown in  FIGS.  1 - 3   , the beam direction A can be adjusted by +/− 30 degrees by tilting the axis A 3 ′ relative to axis A 2 ′, wherein it is possible to rotate the axis A 3 ′ around the axis A 2 ′ by 360 degrees. Tilting by +/− 30 degrees is thus possible in all radial planes through axis A 2 ′. These possible movements are indicated schematically in  FIG.  3    and denoted by reference symbol B. After the adjustment process, the tool  97 ′ is removed from the tube extension  22   a′.    
     Due to the spherical curvature and therefore the constant curvature of the rear wall  13 ′ in all directions, shifting the rear side  19 ′ of the lighting unit  3 ′ by a certain distance always leads to a constant, equal change in the beam angle in relation to the axis A 2 ′. 
     The bar tool  97 ′ is hollow on the inside and therefore has a continuous opening  98 ′ in the longitudinal direction like a tube. During the adjustment, light  99 ′ (see  FIG.  3   ) which is emitted by the lighting unit  3 ′ can exit through the aperture  98 ′. A point of light is thrown into the room, which makes the current beam direction A clear to the operator making the adjustment and helps them to adjust the direction. The light beam angle can therefore be clearly determined by the operator in a simple way during adjustment. 
     Alternatively, the tool  97 ′ could be designed in the form of a rod without a longitudinal continuous opening if the emission of light  99 ′ during adjustment is not desired. 
     A lighting device  1  according to a variant of the first exemplary embodiment is illustrated in  FIGS.  4 - 8   . The explanations provided above for  FIGS.  1 - 3    also apply to  FIGS.  4 - 8   , with the differences described below. In  FIGS.  4 - 8   , elements and features which have already been described in relation to  FIGS.  1 - 3    are denoted by the same reference symbols, but in each case without inverted commas. 
     The lighting device  1  in  FIGS.  4 - 8    in particular differs from the device  1 ′ in that in the lighting device  1 , the lamp housing  2  has access openings  61  in an area between the light output side  5  and the curved, dome-shaped rear wall  13 . Due to the access openings  61  penetrating a side wall of the lamp housing  2 , the lamp housing  2  is largely laterally open in this area. In addition, the overall height of the lamp housing  2  in relation to its diameter is selected to be greater than that of the lamp housing  2 ′. 
     A control device  80  (“driver”) for powering the lighting unit  3  is located outside of the lamp housing  2 . In the case of the lighting device  1 , a wire  65 , in particular a flexible cable, which is only shown in a schematically simplified way in  FIG.  7   , is routed through the access opening  61  into the internal space  12  for the electrical supply of the lighting unit. In this way, the wire  65  connects the lighting unit  3  to the control device  80 , which is positioned outside of the lamp housing  2  and is also only shown in a schematically simplified way in  FIG.  7   . 
     In the two variants of  FIGS.  1 - 8   , the lighting unit  3 ′,  3  is designed in such a way that the lighting unit  3 ′,  3  extends in a longitudinal section along the axis A 3 ′ or A 3  from the light output side  17 ′,  17  to the rear side  19 ′,  19 , initially expanding in the radial direction and then tapered again. The maximum radial dimension of the lighting unit  3 ′,  3  is closer to the light output side  17 ′,  17  than the rear side  19 ′,  19 . This design enables collision-free tiltability within the angular range described above of, for example, +/− 30 degrees in relation to the axis A 2 ′, A 2  while at the same time providing sufficient space for a heat sink  18 ,  18 ′, which enables effective heat dissipation. The heat sink  18 ,  18 ′ is formed with a corner E in the longitudinal section in the area of the maximum radial dimension of the heat sink. 
     In the case of the lighting device  1  in  FIGS.  4 - 8   , the lighting unit  3  is largely located inside of the internal space  12  of the lamp housing  2 , whereas the tube extension  22   a  of the lighting unit  3 , which is in other cases positioned in the same way as the exemplary embodiment in  FIGS.  1 - 3   , protrudes slightly from the light emission opening  8 , see  FIG.  4 - 8   . In contrast, the device  1 ′ of  FIGS.  1 - 3   , features a lighting unit  3 ′ located fully within the internal space  12 ′, wherein part of the tube extension does not project through the aperture  8 ′, either with straight orientation of the lighting unit along the axis A 2 ′ or in an inclined position. 
     In the case of variant of  FIG.  4 - 8   , the beam direction A is adjusted in the same way as in  FIG.  1 - 3    using a tubular tool  97 , the inner passage  98  of which in turn allows light  99  to exit the end of the tool  97  during adjustment and makes it easier for the operator to make the adjustment, see  FIGS.  7  and  8   . In turn, the axis A 3  of the lighting unit  3  can, as shown in the example in  FIGS.  1 - 3   , be inclined by an angle β of up to approximately 30 degrees relative to the axis A 2  of the lamp housing  2  in all radial planes in which the axis A 2  lies. In turn, the axis A 2  in  FIG.  5    runs parallel to the vertical V, for example. 
     The lamp housings  2 ′,  2  in the variants described above are intended for installation in a recess  29 ′,  29  and in the cavity located behind the plate element  25 ′,  25 , wherein installation, for example in a ceiling, wall or floor could be considered. The plate element  25 ′,  25  can therefore be used as a wall or ceiling or floor component. Alternatively, it is also conceivable to mount the lamp housing  2 ′,  2  in an outer housing, which is not shown in the figures. 
       19  and  20  show a lighting device  1 ″ according to a further variant of the first exemplary embodiment. In  FIGS.  19  and  20   , elements and features which have already been described for  FIGS.  1 - 8    are denoted by the same reference symbols, but in each case with double inverted commas. The differences between this variant and those of  FIGS.  1 - 8    are described below, with reference to the above explanations. 
     The lighting device  1 ″ has a lamp housing  2 ″ which is attached to a mounting position in a different way than the housing  2 ,  2 ′. No separately provided assembly set is used in the variant in  FIGS.  19 ,  20   . Instead, the lamp housing  2 ″ has fastening devices  40 ″ which enable the lamp housing  2 ″ to be fastened within a recess  29 ″ in a plate element  25 ″. The fastening devices  40 ″ each feature a tab element  41 ″ and a plurality of mutually offset channels  42 ″, into which an end section of the tab element  41 ″ can be selectively inserted. The channels  42 ″ allow adaptation to different thicknesses of the plate element  25 ″. In other words, the assembly set is integrated into the lamp housing  2 ″. 
     The lamp housing  2 ″ in  FIGS.  19 - 20    has an initial rear-side housing section  50 ″ and a second, front-side housing section  55 ″, both of which are connected using fasteners  53 ″, for example screws. The channels  42 ″ are arranged circumferentially on the front housing section  55 ″. 
     The rear-side housing section  50 ″ is made of steel, for example, and has a curved, dome-shaped rear wall  13 ″ with an external side  14 ″ and an internal side  15 ″ in the same way as the rear wall  13 ,  13 ′, which is attached to a peripheral, cylindrical wall section  52 ″ connects. The front housing section  55 ″ has an encircling, cylindrical wall section  56 ″ and a plate-like wall section  57 ″ which essentially extends perpendicularly to the wall section  56 ″, delimits an internal space  12 ″ in sections at the front and runs around one edge of the wall section  56 ″. The channels  42 ″ are in the wall section  56 ″. On the outside, the wall section  57 ″ features radial ribs  58 ″ which, when the wall section  57 ″ is filled, cemented or plastered in, are covered with filler, cement or plaster and facilitate adhesion. 
     The front housing section  55 ″ has a central, in particular circular, aperture  59 ″ which allows access to the internal space  12 ″. After mounting the lamp housing  2 ″ in the recess  29 ″, a lighting unit  3 ″ can, for example, be easily introduced into the internal space  12 ″ through the aperture  59 ″, see  FIG.  19   . A magnet  23 ″ on a rear side  19 ″ of the lighting unit  3 ″ enables the lighting unit  3 ″ to be attached and adjusted inside on the curved rear wall  13 ″. 
     The lamp housing  2 ″ also has a cover element  26 ″, which is designed as a flat and circular disc formed with a metal material, for example steel, in  FIGS.  19  and  20   . The cover element  26 ″ can be fitted into the aperture  59 ″ and has a central, in particular circular, access opening which serves as a light emission opening  8 ″. In order to fasten the cover element  26 ″ to the second housing section  55 ″, several holding magnets  60 ″, for example three, are arranged adjacent to an edge of the aperture  59 ″ and distributed along its circumference. After the lighting unit  3 ″ has been introduced, the cover element  26 ″ can be magnetically fastened using the magnets  60 ″ and the housing section  55 ″ can then be closed on the visible side, except for the aperture  8 ″. 
     A light emission area  7 ″ is formed with the light emission opening  8 ″ on a light output side  5 ″ of the housing  2 ″. The rear wall  13 ″ is on a rear side  11 ″ of the housing  2 ″, facing away from the light output side  5 ″. The lighting unit  3 ″ can shine light onto a light output side  17 ″ in order to emit the beam through the light emission area  7 ″, wherein the rear side  19 ″ also faces away from the light output side  17 ″ in  FIGS.  19  and  20   . 
     In the longitudinal section of the lighting unit  3 ″, the heat sink  18 ″ of the lighting unit  3 ″ has an area which forms an axial middle area M of the lighting unit  3 ″ between the light output side  17 ″ and the rear side  19 ″ and in which the maximum radial dimension of the heat sink  18 ″ and thus also of the lighting unit  3 ″ is essentially constant and decreases on both sides of this area along the axis A 3 ″ of the lighting unit  3 ″, which in turn makes possible a good, collision-free tiltability of +/− 30 degrees, for example, in relation to the axis A 2 ″. 
     As in  FIGS.  1 - 8   , the lens  21 ″ designed as described above for the lenses  21 ,  21 ′ is surrounded on its light-emitting side by a funnel-like cover and beam-limiting element  22 ″, wherein  FIG.  20    shows that the element  22  is fitted with locking devices  22   b ″ and is attached to this using a catch as part of the lighting unit  3 ″. A tool  97 ,  97 ′ is also used for adjustment in the variant in  FIGS.  19 - 20   , as described above. 
     Analogously to the example in  FIGS.  4 - 8   , the lamp housing  2 ″ has at least one access opening  61 ″ which allows a supply line for the lighting unit  3 ″ to be passed through. The access opening(s)  61 ″ is/are formed in  FIGS.  19 - 20    as cutouts in the wall section  52 ″ starting from its edge coupled to the second housing section  55 ″. 
     The devices  1 ′,  1 ,  1 ″ are ideally designed for use inside a building. For outdoor applications, lighting devices  101 ,  101 ′ according to a second exemplary embodiment and a variant thereof are described below with reference to  FIGS.  9 - 18   . The lighting devices  101 ,  101 ′ are each designed as a light which is protected against the ingress of water and dust, wherein the protection can correspond, for example, to an IP protection class suitable for the type of use. In the case of the lighting devices  101 ,  101 ′, instead of an accessible opening—which in  FIGS.  1 - 8  and  19 - 20    allows adjustment by means of a mechanical intervention of a tool—there is a counter-magnet on the external side of a rear wall of a partially dome-shaped, curved housing  102 ,  102 ′—which in this case is not formed from a ferromagnetic material but, for example, from an aluminium material or a plastic material. 
       9 - 16  show the lighting device  101  according to the second exemplary embodiment, which has a lamp housing  102  and a lighting unit  103  arranged completely within an interior space  112  of the lamp housing  102  when ready for operation. The internal space  112  is closed off from the outside and sealed against the ingress of water and/or dust from the outside. In this way, the lighting unit  103  can be effectively protected against the ingress of moisture and/or dirt when used outdoors. 
     The lamp housing  102  is formed with a light emission area  107  on a light output side  105  thereof. Furthermore, the lamp housing  102  has a curved, dome-shaped or cupola-like rear wall  113  on a rear side  111  that faces away from the light output side  105 . 
     In the second exemplary embodiment, unlike the first embodiment, the housing  102  is illustrated in an example position in which the rear wall  113  faces downward. This illustration is chosen with a view to the exemplary application in the area of a floor, which will be explained in more detail below, but the housing  102  can instead be oriented differently in other applications. 
     In the light emission area  107 , the lamp housing  102  has a translucent cover  141 , which is, for example, a translucent or transparent pane, such as a glass pane, and by means of which the lamp housing  102  is tightly closed on the light output side  105 . The cover  141  is sealed against other housing components with a seal  143 , which is made of silicone, for example. 
     The lighting unit  103 , which can be moved in the internal space  112 , has a heat sink  118 , wherein a printed circuit board  120   a  featuring an LED device  120 , a lens  121  and a cover element  122  are substantially arranged concentrically to each other and the heat sink  118  along a central longitudinal axis A 103  of the lighting unit  103 . 
     During operation, the lighting unit  103  emits light on a light output side  117  of the same, which is generated by the LED device  120   b  and directed and/or focused in the desired manner by the lens  121  arranged in the output direction A in front of the LED device  120   b . The cover element  122  has a central, circular access opening, see Fig. The cover element  122  also has a conical surface section that extends in a ring shape around the access opening. 
       FIG.  9    shows that the lighting unit  103  is arranged in the internal space  112  in such a way that it can let the light emitted on its light output side  117  shine through the light emission area  107  of the lamp housing  102  and thereby through the cover  141  . The light emission area  107  of the housing  102  in the second exemplary embodiment is larger than the light emission opening  8 ,  8 ′,  8 ″ in the first exemplary embodiment and its variants and essentially occupies the entire diameter of the lamp housing  102  on its light output side  105 . While the lens  21 ,  21 ′,  21 ″ in the first exemplary embodiment is ideally adapted for diffusion through small or narrow apertures, this is not required in the same way for the lens  121 . The lens  121  is therefore of a different type than the lenses  21 ,  21 ′,  21 ″ in preferred exemplary embodiments. 
     Furthermore, a rear side  119  of the lighting unit  103 , which is opposite the light output side  117  and thus faces away, features a permanent magnet  123 , which is ring-shaped, for example, with the central longitudinal axis A 103  of the lighting unit  103  coinciding with a central axis of the magnet  123 . The magnet  123  can be screwed to the heat sink  118 , for example. Using the magnet  123 , the lighting unit  103  is attached to a selectable location on the rear wall  113  of the lamp housing  102 , wherein a selected alignment of the axis A 103  of the lighting unit  103  and thus a selected main beam direction A is fixed and is adjustable. 
     The adjustment of the beam direction A and the fastening of the lighting unit  103  is accomplished in the second exemplary exemplary embodiment using a tool  197  provided for this purpose. The tool  197  also has a permanent magnet, which can interact with the magnet  123  by attracting one another using, for example, a counter-magnet  147  in the shape of a ring or disk. By arranging and moving the tool  197  and thus the counter-magnet  147  on the external side  114  of the rear wall  113 , the orientation of the axis A 103  is adjusted by moving the rear side  119  along the rear wall  113  without needing to access the internal space  112 . The attraction between the magnets  123 ,  147  pulls the rear side  119  of the lighting unit  103  against an internal side  115  of the rear wall  113 , as a result of which the selected orientation of the lighting unit  103  is also fixed. This allows the lighting unit  103  can be effectively protected against the effects of external moisture and dirt by sealing the housing interior  112 . Direct mechanical access is avoided. 
     The lighting device  101  of the second exemplary embodiment is also designed as a built-in light, wherein the lamp housing  102  is designed to be accommodated and installed in a cavity or a recess  129  in an outer housing  189 . This in turn has four ball plungers  131  to mount the lamp housing  102 , which are arranged uniformly around the circumference of the housing  102  and are each spaced at 90 degrees to each other, each featuring a spring-loaded ball  32  which enables the detachable lamp housing  102  to be snapped into the outer housing  189 ; cf. the example the sectional views in  FIGS.  9 - 11    and  FIG.  14   . 
     The outer housing  189  can in particular be accommodated in the floor area. In this case, a central housing axis A 102  can run along a vertical direction V, see  FIG.  9   , in which case the lighting device  101  can shine upwards in different directions from the perspective of the viewer. An alternative installation in the area of a wall or ceiling outdoors is also conceivable. 
     In the installed state, see for example  FIG.  10   , the lamp housing  102  closes with its outer surface on the light output side  105  essentially flush with a surface  127  in the vicinity of the installed light housing  102 . The surface  127  can be, for example, a floor surface, wherein a cavity to receive the outer housing  189  can be created in the floor. However, surface  127  could be a wall or ceiling surface for wall or ceiling mounting, for example. 
     Another ball plunger  153  is also arranged concentrically in relation to the axis A 103  in the centre on the rear side  119  of the lighting unit  103  and is surrounded by the ring-shaped magnet  123 . The ball plunger  153  helps with the adjustment. A spring-loaded ball  159  of the ball plunger  153  acts on an internal side  115  of the curved, dome-shaped rear wall  113 . An internal surface on the internal side  115  of the rear wall  113  is formed as part of a spherical surface. An outer surface on the external side  114  is also curved in the shape of a dome and is designed as part of a spherical surface. However, while the rear wall  113  is essentially smooth on the external side  114  and enables the tool  197  to be moved smoothly on the external side  114 , the internal side  115  of the rear wall  113  has a plurality of concentric grooves  171  in which the balls  159  can engage by locking in a detachable manner. 
     In this way, the tilt angle of the axis A 103  of the lighting unit  103 , and thus the main beam direction A, can be adjusted in predefined stages in relation to the housing axis A 102  through the interaction of the ball plunger  153  and the grooves  171  in the rear wall  113 , which is made of a non-ferromagnetic material, in particular a plastic or aluminium or an aluminium alloy, and through the attraction of the two magnets  123  and  147  to each other. At the same time, the axis A 103 , and thus the main beam direction A, can be continuously rotated about the vertically oriented housing axis A 102 , wherein the ball  159  runs in the groove  171  in which it is currently engaged. The grooves  171  may be spaced such that the tilt angle of the axis A 103  is adjustable in increments of, for example, 5 degrees. 
     However, the grooves  171  can be omitted in variants of the second exemplary embodiment, which then allows the tilt angle of the axis A 103  to the axis A 102  to be adjusted in an infinitely variable manner. In such a variant, the ball plunger  153  can be retained in order, for example, to enable the rear side  119  of the lighting unit  103  to be moved more easily along the rear wall  113 . 
     The lighting unit  103  initially widens radially in a longitudinal section of the same from the light output side  117  to the rear side  119  and then narrows again. As in the first exemplary embodiment in  FIGS.  1 - 3    and its variant in  FIGS.  4 - 8   , in the lighting unit  103  an area of a maximum radial dimension of the lighting unit  103  is formed closer to the light output side  117  than to the rear side  119 , see for example  11  It is therefore possible to accommodate a heat sink  118 , which can effectively dissipate the heat generated by the LED device  120   b  and at the same time achieve adjustability within the desired angular range. In the second exemplary embodiment, the lighting unit  103  also has a corner E in the area of the maximum radial dimension. 
     In the case of the lighting device  101 , a wire, which is not shown in the figures, for the electrical supply of the lighting unit  103  is fed out through a sealed channel  167  from the internal space  112  of the lamp housing  102 . The sealed channel  167  is located on the rear side  111  of the lamp housing  102 , penetrates the rear wall  113  and is sealed separately, for example using a screw connection. In the second exemplary embodiment, a control device or “driver” (not shown in the drawing) can be located outside of the lamp housing  102  and is connected to the lighting unit  103  using the wire in the manner described above. 
     On the rear side  111  of the housing  102 , a small area occupied by the channel  167 , see  FIG.  13   ,is therefore not accessible to the counter-magnet  147  and subsequently also the tool  197 . If the lighting unit  103  is to be adjusted into a position for which the tool  197  would need to be placed in the area of the channel  167 , this can be achieved during assembly by inserting the housing  102  into the outer housing  189  in a rotated manner, for example by rotating it approximately 90 or 180 degrees. In this way, all desired beam angles can be achieved in the sealed second exemplary embodiment. 
     Outer housing  189  may be formed with an outer, lower portion  190  and an inner, upper portion  191 , as diagrammatically illustrated in  FIGS.  9 - 16   . The lower part  190  can form a base-like element, which can be placed, for example, in a floor area, for example in a channel in the floor, and can be fastened using a flange  192  with fastening openings at the lower end of the part  190 . The lower part  190  is wider towards the bottom, giving it a stable footing, and is hollow on the inside. In the upper region of the lower part  190 , the upper part  191  is accommodated in sections as an insert, see for example  FIG.  14   , wherein the upper part  191  is also hollow inside and accommodates the lamp housing  102 . The lamp housing  102  can be latched onto the upper part  191  using the ball plunger  131 , wherein the balls  32  click into a rear edge of the part  191 . 
     As is particularly clear in the top view, the lower part  190  of the outer housing  189 , see for example  FIGS.  11 - 13   , has a flat side  193  that facilitates placement of the outer housing  189  near walls, for example, near an outer wall of a building. This can be useful if the lighting unit  103  is equipped with lenses that form a narrow cone of light and need to be placed close to the wall to create a lighting effect. 
       17 ,  18  also illustrate a lighting device  101 ′ according to a variant of the second exemplary embodiment, the above explanations relating to  FIGS.  9 - 16    also being applicable to  FIGS.  17  and  18   , with the differences described below. In  FIGS.  17 ,  18   , elements and features which have already been described in relation to  FIGS.  9 - 16    are denoted by the same reference symbols but with an additional inverted comma. 
     In the case of the lighting device  101 ′, the outer housing  189 ′, as another example, is in particular shaped symmetrically and is designed as one piece, see  FIG.  17   . The lamp housing  102 ′ is therefore inserted directly into the hollow and tube-like outer housing  189 ′ from above and is fixed in a detachable manner using the ball plunger  131 ′. 
     In the variant of  FIGS.  17 ,  18   , a gradual adjustment of the tilt angle β of the central longitudinal axis A 103 ′ of the lighting unit  103 ′ in relation to the axis A 102 ′ of the lamp housing  102 ′ is also provided. As also illustrated in the top view of  FIG.  18   , a gradual adjustment in 5-degree increments is possible with the aid of concentric grooves  171 ′. Some possible setting angles β6=βmax=30 degrees, β4=20 degrees, β2=10 degrees and β0=0 degrees are shown in Fig. In the example shown in  FIG.  17   , an angle of γ=90 degrees−βmax=60 degrees thus remains between the horizontal and the maximum tilt angle βmax. 
       FIG.  17    also illustrates the cone of light K generated by the lighting unit  103 ′ during operation, which is emitted out of the device through the cover  141 ′. 
     In the second exemplary embodiment and its variants, the beam direction A can be tilted by up to approximately 30 degrees in relation to the axis A 102 , A 102 ′ of the lamp housing  102  and can also be rotated about the axis A 102 , A 102 ′ as described above. 
     Although the present invention has been fully described above with reference to the preferred exemplary embodiments, it is not limited to these exemplary embodiments and can be modified in a variety of other ways. 
     Variants with infinitely variable or gradual adjustability are in particular conceivable in embodiments for both outside and internal use. For example, in the case of gradual adjustability of the beam direction from the rear side of the lighting unit, an additional, centrally arranged ball plunger could also be provided in an embodiment for the interior in order to implement the gradual adjustability. The rear wall  13 ′,  13 ,  13 ″ in the first exemplary embodiment can thus have concentric grooves  171  in a further variant along the same lines as the second exemplary embodiment. 
     In addition, it should be noted that although the present invention can be favourably used for lights intended for use in a recess, the invention is not limited to recessed lights. Furthermore, although it is favourable to attach the lamp housing so that it can be detached using the ball plunger described above, the lamp housing can also be attached in other, equally useful ways. 
     REFERENCE LIST 
     
         
           1 ,  1 ′,  1 ″ Lighting device 
           2 ,  2 ′,  2 ″ Lamp housing 
           3 ,  3 ′,  3 ″ Lighting unit 
           5 ,  5 ′,  5 ″ Light output side 
           7 ,  7 ′,  7 ″ Light emission area 
           8 ,  8 ′,  8 ″ Light emission opening 
           11 ,  11 ′,  11 ″ Rear side (lamp housing) 
           12 ,  12 ′,  12 ″ Internal space (lamp housing) 
           13 ,  13 ′,  13 ″ Rear wall (lamp housing) 
           14 ,  14 ′,  14 ″ External side (rear wall) 
           15 ,  15 ′,  15 ″ Internal side (rear wall) 
           15   a ,  15   a ′ Internal surface 
           17 ,  17 ′,  17 ″ Light output side (lighting unit) 
           18 ,  18 ′,  18 ″ Heat sink 
           19 ,  19 ′,  19 ″ Rear side (lighting unit) 
           20   a ,  20   a ′ Circuit board 
           20   b ,  20   b ′ LED device 
           21 ,  21 ′,  21 ″ Lens 
           22 ,  22 ′,  22 ″ Cover and beam-limiting element 
           22   a ,  22   a ′ Tube extension 
           22   b ″ Locking device 
           23 ,  23 ′,  23 ″ Magnet 
           25 ,  25 ′,  25 ″ Plate element 
           26 ,  26 ′,  26 ″ Cover element 
           27 ,  27 ′ Surface (plate element) 
           29 ,  29 ′,  29 ″ Recess 
           31 ,  31 ′ Ball plunger 
           32 ,  32 ′ Ball 
           35 ′ Assembly set 
           37 ,  37 ′,  37 ″ Coupling device 
           40 ″ Fastening device 
           41 ″ Tab element 
           42 ″ Channel 
           50 ″ First housing section 
           52 ″ Wall section 
           53 ″ Fastener 
           55 ″ Second housing section 
           56 ″ Wall section 
           57 ″ Wall section 
           58 ″ Rib 
           59 ″ Aperture 
           60 ″ Holding magnet 
           61 ,  61 ″ Access opening 
           65  Wire 
           80  Control device 
           97 ,  97 ′ Tool 
           98 ,  98 ′ Continuous opening 
           99 ,  99 ′ Light 
           101 ,  101 ′ Lighting device 
           102 ,  102 ′ Lamp housing 
           103 ,  103 ′ Lighting unit 
           105 ,  105 ′ Light output side 
           107 ,  107 ′ Light emission area 
           111 ,  111 ′ Rear side (lamp housing) 
           112 ,  112 ′ Internal space (lamp housing) 
           113 ,  113 ′ Rear wall (lamp housing) 
           114 ,  114 ′ External side (rear wall) 
           115 ,  115 ′ Internal side (rear wall) 
           117 ,  117 ′ Light output side (lighting unit) 
           118 ,  118 ′ Heat sink 
           119 ,  119 ′ rear side (lighting unit) 
           120   a ,  120   a ′ Circuit board 
           120   b ,  120   b ′ LED device 
           121 ,  121 ′ Lens 
           122  Cover element 
           123 ,  123 ′ Magnet 
           127  Surface 
           129 ,  129 ′ Cavity 
           131 ,  131 ′ Ball plunger 
           141 ,  141 ′ Cover 
           143 ,  143 ′ Seal 
           147 ,  147 ′ Counter-magnet 
           153  Ball plunger 
           159 ,  159 ′ Ball 
           167  Sealed channel 
           171 ,  171 ′ Groove 
           189 ,  189 ′ Outer housing 
           190  Outer section 
           191  Inner section 
           192 ,  192 ′ Flange 
           193  Flat side 
           197 ,  197 ′ Tool 
         A Main beam direction 
         A 2 , A 2 ′, A 2 ″ Axis (lamp housing) 
         A 102 , A 102 ′ Axis (lamp housing) 
         A 3 , A 3 ′, A 3 ″ Axis (lighting unit) 
         A 103 , A 103 ′ Axis (lighting unit) 
         B Movement 
         D 8 ′ Diameter 
         E Corner 
         K Cone of light 
         M Middle area 
         S Visible side 
         V Vertical 
         β Light beam angle 
         β max Maximum tilt angle 
         β 0 , β 2  Angle 
         β 4 , β 6  Angle 
         g Angle