WO2012032454A1

WO2012032454A1 - Adjustable lamp cap for tube-lamp replacement led lamp

Info

Publication number: WO2012032454A1
Application number: PCT/IB2011/053870
Authority: WO
Inventors: Pieter Joseph Clara Van Der Wel
Original assignee: Koninklijke Philips Electronics NV
Current assignee: Koninklijke Philips NV
Priority date: 2010-09-08
Filing date: 2011-09-05
Publication date: 2012-03-15
Anticipated expiration: 2013-03-08
Also published as: TW201221840A

Abstract

A lighting device (100) for replacing a conventional tube lamp comprises an illuminator part (120) sleeved with a cap part (110) acting as adaptor between the illuminator part and an electric socket (190). Unlike a conventional tube lamp, the illuminator part produces an azimuthally uneven spatial light distribution, but can be oriented as desired with respect to the socket by being connected to the cap part at one of a plurality of available positions. In each connected position, form-locking elements (116, 126) restrict relative rotation (R) of the parts. The lighting device may further include detachable axially locking elements.

Description

Adjustable lamp cap for tube-lamp replacement LED lamp

FIELD OF THE INVENTION

The invention disclosed herein belongs to the field of electric lighting and more precisely relates to an adjustable lamp cap. One particular application of the invention is a low-energy and/or long-life light source for replacing a tube lamp.

BACKGROUND OF THE INVENTION

An important class of contemporary 'low-energy' lighting devices are designed to replace incandescent light bulbs, fluorescent tube lamps or other less energy- efficient lighting technologies. Users expect perfect or near-perfect backward compatibility with existing fittings, and this is also desirable from the point of view of market penetration. Ensuring backward compatibility includes providing low-energy light sources with contacting means, in particular threaded, plug-like or bayonet-type sockets, that fit those lamp caps and fittings that have established as standards in the concerned geographic region. Backward compatibility of a light source may also take into account that its light emission pattern is different from that of corresponding conventional devices, e.g., regarding intensity, wavelength spectrum and spatial distribution.

A threaded lamp cap is adapted for receiving a (azimuthally omnidirectional) light bulb and will normally retain the bulb at a predetermined azimuthal orientation in the electrically connected position. Tube-lamp mountings, which are generally of bayonet or (two-pin) plug-and-socket type, are a further example wherein only one predetermined relative orientation between the light source and the mounting is available. Hence, the problem which will be exemplified below is relevant to a larger class of light sources than just tube lamps.

US7052171 discloses a light source of tube-like outer shape and including an array of light-emitting diodes (LEDs) having a spatial light distribution different from that of a conventional tube lamp. A tube lamp, which the light source of US7052171 is intended to replace, has a light distribution pattern that is essentially omnidirectional in the azimuthal direction, that is, little difference will be noticed if the tube lamp is rotated around its longitudinal axis. Because the light source of US7052171 is not completely omnidirectional but provides a maximal intensity at a particular emission angle (or this intensity is achieved for several angles), it should preferably be oriented in such manner that the object to be illuminated is located in this direction. To account for the fact that a conventional fitting for tube lamps does not allow the lamp to swivel in its connected position, the light source of US7052171 is connected via revolving adapters which are retained in the azimuthal direction by releasable torsion springs. This light source may be adjusted after being connected to a tube-lamp fitting, but would be improper for consumer products, its contemplated primary application being lighting of an aircraft cabin. To spare the sophisticated mechanical arrangements, unnecessary adjustments are preferably avoided, such as by arranging the light source within a housing, behind a cover glass or the like. As far as a product for purchase and operation of non-professional users is concerned, such limitations are difficult to enforce. Additionally, the cost of the product is not competitive on the consumer market.

SUMMARY OF THE INVENTION

It is an object of the present invention to alleviate the above problem. In particular, it is an object to provide robust and cost-efficient mounting means allowing a light source to replace a previous light source in spite of having a different spatial light distribution than the previous light source. It is a further particular object to replace a previous light source having a spatial light distribution that is omnidirectional with respect to at least one spatial coordinate by a light source that can be repositioned with respect to this coordinate. More specifically, it is envisaged to enable the replacement of conventional incandescent or fluorescent electric light sources by energy-efficient light sources, including LED-based light sources.

Hence, according to a first aspect of the invention, a lighting device as defined in claim 1 is provided. That is, the lighting device comprises an illuminator part and a cap part which are securable together in at least two positions with distinct relative orientations. The illuminator part has a substantially cylindrical shape and is operable to provide an azimuthally uneven light distribution. A first end of the cap part can engage a socket, while a second end of the cap part can engage the illuminator part. In both (or either of the) connected positions, the parts engage in an azimuthally form-locking fashion.

Thus, the lighting device according to the invention comprises at least two parts. Firstly, the device has one cap part acting as an adapter vis-a-vis a socket (e.g., a lamp cap secured at a luminary and connected to electric power) allowing connection at a very limited number of orientation options. For example, a plug with two diametrically arranged plugs may offer one or, if inversion of the pins can be effected, two possible orientations. The cap part is further adapted to mate with an illuminator part of substantially cylindrical or tube-like outer shape. The invention is not restricted to illuminator parts shaped as cylinders that have circular cross-section, but includes cylinders with arbitrary cross sections, including elliptic, oval, polygonal and irregular shapes. An illuminator part may even differ

substantially from the shape of an ideal cylinder as long as it is rotatable within the free space normally allowed for a light source of the type it is intended to replace. (For the purpose of this description and for construing the appended claims, the concept of an azimuthal direction is adapted accordingly; if for instance, from the reference point of the cap part, the possible orientations of the illuminator part differ by rotations around an axis, the direction of these rotations around the axis will be referred to as azimuthal and the direction of the axis as axial. In constructive terms, one may consider illuminator parts with any geometric shape that gives rise to a solid of revolution substantially contained inside the geometry of the light source it is intended to replace. For instance, the illuminator part may have the shape of a tube lamp with recesses, as appropriate with regard to the type of light source provided within the illuminator part. Independently of the retrofitting aspect, the invention may also be used to give any light source an enhanced adaptability and versatility, e.g., to enable a user to switch between light pattern orientations associated with different atmospheres or moods.

The invention achieves at least one of the above-mentioned objects in that the cap part and illuminator part are securable in a plurality of positions including at least two distinct relative orientations and thereby offering a user at least two options to choose from. Preferably, the parts can be released and secured again while preserving the range of possible relative orientations. This allows subsequent readjustments of the light source in the luminary, in which it is secured, or subsequent adaptation to a second luminary. In each of their secured positions, the parts engage each other in a form-locking (or form-fit or positively fitting or positively locking or keyed) manner, so that azimuthal rotation is prevented or limited in a mechanically robust manner.

In embodiments wherein the parts can be released, the parts may be freely movable in the axial direction (wherein the integrity of the device may be ensured by the action of gravity compressing an upper part against a lower part), or may engage detachably by virtue of resilient locking means, elastically deformable form-locking elements, mating surfaces engaging frictionally, or by similar measures.

In an advantageous embodiment, the cap part and illuminator part may be securable in two positions the relative orientations of which differ by less than 180 degrees. This feature gives the lighting device an adaptability representing an improvement over the simple possibility of inverting a two-pin connector, as noted above.

From a more general point of view, the relative orientations of the available connected positions offered by the invention are not necessarily spaced by a constant step size, but may as well be unequally distributed, or may be distributed only over a bounded subinterval. Examples of relative orientations defined by the set of connected positions include: 0, 10, 20, 30 degrees; 0, 90, 180, 270 degrees; 0, 10, 60, 75, 90 degrees; 0, 90, 180 degrees; 0, 20, 40, 50, 55, 60, 70, 90 degrees.

In one embodiment, the cap part may be sleeved with the illuminator part. Thus, two mating surfaces may be defined in the sleeved portion, which make contact when the parts are in one of their connected positions. A portion of the cap part may be adapted for introduction into the illuminator part. The cap part may also be adapted to receive a portion of the illuminator part, which may be preferable from the point of view of electrical safety. More specifically, if ohmic contact pads are provided on or near the mating surfaces, the live electric pad may be arranged on a mating surface facing inwardly, that is, in the recess constituting the sleeved portion of the cap part, which may help avoid inadvertent touching.

In one embodiment, the form-locking action may be achieved by protrusions on one of the mating surfaces. Elements for cooperating with these protrusions are arranged on the opposite mating surface and may have the form of protrusions or recesses adapted to limit relative (azimuthal) rotation of the two parts. The protrusions may be ridges, strips, bands, bars, ribs, pins, studs, waves or the like. The recesses may be grooves, cuts, slits, notches, holes or any counterpart to the corresponding protrusions. The protrusions and/or recesses may be equally or unequally spaced over the respective mating surface.

In one particular embodiment, a plurality of parallel grooves are provided on one or both mating surfaces. The grooves are adapted to cooperate with an element on the other surface, so as to achieve the form-locking action.

In one embodiment, the form-locking elements extend outside the sleeved portion. For instance, an illuminator part may at the outset be provided with grooves serving an aesthetic, optical, heat-radiating or other functional purpose and may at the same time provide sufficient unevenness for reciprocal elements to engage in a rotation-locking fashion. In particular, the illuminator part may comprise a translucent light diffuser with axial grooves for influencing (or modifying or adjusting or tuning) the light distribution. The second end of the cap part, which engages the illuminator part, may then be arranged in the form of a sleeve equipped with protrusions engaging a portion of the grooved light diffuser. When the illuminator part and cap part are fitted together, the protrusions enter into the grooves and prevent the cap part from rotating relative to (the axis of the) the illuminator part in the azimuthal direction.

In one embodiment, the relative mobility of the cap part and the illuminator part is limited in the axial direction as well, when these are in a connected position. To achieve this, the cap part may comprise an axially locking element adapted to cooperate with an element on the illuminator part. Advantageously, the axially locking element and its reciprocal are adapted to engage in more than one connected position of the parts, and preferably in all available connected positions.

In an alternative further development of this embodiment, the axially locking element is a rib, ridge or groove extending in the azimuthal direction, preferably around the respective part. The reciprocal element of the other part, which serves to retain the axially locking element in the connected position, may be resilient, preferably in the radial direction or a direction near this. The resilience ensures that the two parts will not slip apart in normal circumstances, but on the other hand enables a user to detach the parts relatively easily in order to select a new desired relative orientation and reconnect the parts.

In a second further development of this embodiment, an axially locking element is a groove extending azimuthally and cooperating with at least one spring-loaded pin adapted to snap into and out of the groove. Advantageously, the pin may function as an electric connector adapted to make contact with an ohmic contact pad disposed at the bottom of the groove. The groove with the contact pad is preferably disposed on the surface of the cap part, so as to protect the live electric pad.

In one embodiment, the cap part and/or the illuminator part is equipped with a marker for indicating a relative orientation of the parts. This facilitates uniform configuration of several similar lighting devices, especially if the relative orientations of the available connected positions differ by small steps.

In one embodiment, the illuminator part is securable to two cap parts simultaneously. This means that the illuminator part with its cap parts can be connected to a conventional tube-lamp fitting. In accordance with the inventive concept, the orientation of each cap part with respect to the illuminator part is adjustable.

In one embodiment, the illuminator has a tube-like shape and comprises a plurality of light-emitting diodes (LEDs). This embodiment is well suited to replace a conventional tube lamp, which may be less energy- efficient than LEDs or may contain environmentally hazardous mercury. It is emphasized that the present application claims protection also for an illuminator part per se and a cap part per se. Although the respective parts have up to now been discussed jointly, their properties and advantages fall within the inventive concept even when considered alone. Further, it is noted that the invention relates to all possible combinations of features recited in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiments of the invention. On the drawings:

figure la shows, in accordance with an embodiment of the invention, a detached two-part lighting device for connection to a bayonet socket;

figure lb shows the lighting device of figure la in a first connected position; figure lc shows the lighting device of figure la in a second connected position;

figure 2 shows an embodiment wherein the axial directions of the respective ends of the cap part are distinct;

figure 3 shows, in accordance with an embodiment of the invention, a detached lighting device wherein the illuminator part has an extension portion separating it from the cap part which is, in turn, adapted for connection to a straight two-pin socket;

figure 4 shows a detached lighting device, wherein refractive axial ridges on the illuminator part serve as azimuthally form-locking elements and wherein markers indicating the relative orientation are arranged;

figure 5 is a transversal cross-sectional view of the sleeved portion of a connected cap part and illuminator part;

figure 6 includes, on the one hand, a transversal cross- sectional view of the sleeved portion of a connected cap part and illuminator part and, on the other, an external side view showing an axially locking element on the inner part;

figure 7 shows a further arrangement for detachably locking the connected parts against axial movement;

figure 8 is a transversal cross-sectional view showing azimuthally form- locking elements connectable at fixed relative orientations distributed over a bounded angular interval; figure 9 shows an arrangement for connecting the two parts electrically irrespective of their actual relative orientation; and

figure 10 shows a lighting device wherein the illuminator part is connectable, at selectable relative orientations, to two cap parts.

Unless otherwise indicated, like reference numerals are used for like elements.

DETAILED DESCRIPTION

Figure 1 is a perspective side view of a lighting device 100 comprising a cap part 110 and an illuminator part 120. The illuminator part 120 comprises an arrangement of at least one light source 121, such as a light-emitting diode (LED), which is operable to emit light distributed unevenly with respect to the azimuthal space coordinate R. The cap part 110 engages at either of two possible orientations, differing by 180 degrees, to a bayonet socket 190 with elongated holes 198, 199 adapted to receive corresponding pins 118, 119 on a first side 111 of the cap part 110. The illuminator part 120 connects to the cap part 110 when inserted along the axial direction T into a recess 115 on the second side 112 of the cap part 110. In the connected position, as shown in figure lb, a form-locking action is achieved by ridges 116 in the recess 115 which cooperate with grooves 126 on a protruding portion of the illuminator part 120, so that no (or at least only limited) relative rotation is possible in the connected position. However, the illuminator part 120 can be pulled out of its connected position, along the axial direction T. When detached, it can be rotated in the azimuthal direction R and then reinserted to be reconnected in a new locking position, as shown in figure lc.

Figure 2 shows a lighting device including an illuminator part 220 and a cap part 210 connectable to a bayonet-type socket 290, wherein respective mating surfaces 215, 225 make contact. Just like the lighting device of figure 1, this arrangement provides a possibility to reorient the illuminator part 220 in its azimuthal direction R. However, it also affords the user with a latitude to connect a lighting fitting that extends in a different direction than the rotary axis of the bayonet mechanism of the socket 290. In figure 2 this is exemplified in that the two main axes of the cap part 210 - i.e., the direction of the parallel connection pins 218, 219 as well as the longitudinal direction of the mating surface 215 provided at the connection end for connecting the illuminator part 220 - are disposed at an angle of approximately 90 degrees. Variations to the present embodiment may feature a different relative angle of the axes. In these variations, the cap part 210 may further include several connector ends for connecting one or more illuminator part 220 in one of several selectable directions. This enables the direction in which the illuminator part extends to be varied.

Figure 3 shows, according to another embodiment of the invention, a lighting device for connection to a two-pin socket 390 with straight holes 398, 399 for receiving corresponding connection pins 318, 319 of a cap part 310. The illuminator part 320 comprises a plurality of light sources 321 arranged on a reflector plate 322. The illuminator part 320 comprises a grooved mating surface 325, which however differs from the preceding embodiments by being separated by an extension portion 323 from the light-emitting portion of the illuminator part 320. In variations to this embodiment, such extension portion need not be straight and centered, but may be bent or have a shape by which the parts obtain an eccentric relative position (having non-coinciding, preferably parallel, longitudinal axes).

Figure 4 shows a two-part lighting device, wherein the illuminator part 420 has a translucent, axially ridged outer surface for refracting and distributing light emitted by light sources 421 arranged inside the illuminator part 420. Longitudinal grooves 426 arise between the ridges, into which stop pins 416 on a cap part 410 enter when this is connected to the illuminator part 420. This prevents the illuminator part 420 from rotating with respect to the cap part 410. This embodiment comprises nine evenly spaced grooves 426, so that the parts are connectable at nine distinct positions. In each connected position, markers 430, 431 on the respective parts indicate an angle indicative of this position.

Figure 5 shows, in transversal cross section, the sleeved portion of a two-part lighting device in a connected position. An outer part 510 of the lighting device has inward ridges 516, which engage grooves 526 provided on an inner part 520. To enable connection and disconnection, the grooves 526 preferably extend longitudinally and open towards the other part. Alternatively, the outer part 510 has resilient studs 516 adapted to snap into point- like holes 526 on the inner part 520, thereby fixing the parts against relative movements both in the axial and the azimuthal direction. The outer part 510 is an illuminator part and the inner part 520 is a cap part, or vice versa.

Figure 6 illustrates a lighting device comprising, with reference to its six connected positions, an inner 601 and outer 602 part, which are both azimuthally and axially locking. The azimuthal locking action is achieved by the hexagonal inner and outer shapes of the respective parts 601, 602, as illustrated by the cross- sectional view in the left portion of the figure. As shown both by this view and the side view in the right portion, the inner part 601 has a circumferential groove 604 adapted to receive resilient protrusions 603 extending from the outer part 602 in the inward radial direction. The protrusions 603, which may be realized as spring-loaded pins, snap into the groove 604 upon insertion of the inner part 601 into the outer part 602. The stiffness of the protrusions 603 is such that the parts 601, 602 are kept together during normal use but are still easy to disconnect without damaging the protrusions 603. The outer part 602 is an illuminator part and the inner part 601 is a cap part, or vice versa.

Figure 7 illustrates an embodiment which advantageously establishes electric connection between the illuminator part 120 and the cap part 110 and at the same time locks the parts axially. More precisely, a recessed ohmic contact pad 114 extends azimuthally around the cap part and is electrically connected to either of its conductive pins 118, 119 for connection to a (bayonet- type) socket. The other conductive pin is connected to a resilient contact sheet 113 on the interior axial end surface of the cap part 110. It is advantageous from a product- safety point of view to combine this embodiment with a non-invertible socket, so that it can be ensured that the contact sheet 113, which may be within reach of a finger, is the neutral, non-live connector. When the illuminator part 120 is introduced into the cap part 110, outward resilient pins 124 on the illuminator part 120 snap into the recessed contact pad 114, and a flat contact pad 123 on the axial end surface of the illuminator part 120 makes contact with the contact sheet 113. This establishes a two-pole electric connection for powering each of a plurality of light sources 121 in the illuminator part 120. The connection is broken as soon as the parts are disconnected. The contact sheet 113 and the flat contact pad 114 preferably have such shape that connection will be established irrespective of the relative orientation of the parts. Similarly to the preceding embodiments, axial ribs 116a, 116b on the inside of the cap part 110 serve as azimuthally locking elements. In a variation to this embodiment, the two electric connections may be achieved by means of two (axially spaced) recessed circumferential contact pads, so that neither the neutral nor the live pad is possible to touch.

Still with reference to electric connections, figure 9 shows an embodiment wherein socket connection pins 918, 919 of a cap part 910 are connected to resilient (e.g., spring- suspended) contact pads 908, 909, spaced in the radial direction. Upon insertion of the illuminator part 920 into the cap part 910 along the axial direction T, corresponding contact pads 918, 919 will lie proximate to the resilient pads 908, 909, thus in electric contact therewith so that light sources 921 in the illuminator part 920 are powered. By the shape of the contact pads, this electric contact will establish irrespective of the relative orientation of the parts 910, 920. It is advantageous from an electric safety point of view that the hollow portion of the cap part 910 extends so deep that it would be difficult to touch the resilient pads 908, 909 - at least the live pad - with a finger or the like. For example, the cap part 910 may be translucent and contain the entire illuminator part 920 when connected to this.

Figure 8 is a further transversal cross -sectional view of an inner 801 and an outer part 802 (respectively acting as illuminator part and cap part, or vice versa) in their connected position. An azimuthally locking action is achieved by means of cooperating toothed portions 803, 804 of the outer 802 and inner 801 parts respectively. On either part, the teeth may extend axially or may be localized to a portion of each part. The toothed portions 803, 804 subtend respective angles β and a, implying that the available relative orientations of the parts 801, 802 differ by at most β - a (not counting the potential further variability by 180 degrees which an inversion of the cap part with respect to the socket affords). Such restricted range of variations may still be adequate if the light distribution pattern produced by the illuminator part is not completely different in all directions, e.g., if it repeats periodically. An advantage of restricting the range of variation in this fashion is that the design of the electric contact means between the parts can be simplified.

Figure 10 shows a three-part lighting device adapted for connection to a conventional tube-lamp fitting 1090. Such a fitting 1090 may comprise two straight-pin sockets, or two sockets with transverse, half-open notches adapted to receive contact pins and revolvable to a closed position in which the contact pins are shut in, or one notch socket and one bayonet socket, or some other assembly practiced in the art. The lighting device comprises an illuminator part 1020 comprising light sources 1021 and being connectable, at both ends 1022, 1023, to respective cap parts 1010 a, b. Similarly to the embodiments discussed previously, each cap part 1010 a, b engages the respective illuminator part 1020 a, b in an azimuthally form-locking manner when connected, but is detachable for reconnection at one of the other available relative orientations.

The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, each of the embodiments may be supplemented by a reflector arranged in the illuminator part so as to improve the directivity of the light source without using external reflectors, which are often sub-optimal from the point of view of energy efficiency and bulkiness.

Claims

CLAIMS:

1. A lighting device (100) comprising:

an illuminator part (120; 220; 320; 420; 920; 1020), which has a substantially cylindrical shape and is operable to provide an azimuthally uneven light distribution; and a cap part (110; 210; 310; 410; 910; 1010) engageable, at a first end (111; 1022), to a socket (190; 290; 390) and, at a second end (112; 1023), to the illuminator part, wherein the cap part and the illuminator part are securable together in at least two positions with distinct relative orientations, wherein the cap part and the illuminator part engage in an azimuthally form-locking fashion in both positions.

2. The lighting device of claim 1, wherein the relative orientations of two positions differ by less than 180 degrees.

3. The lighting device of claim 1, wherein the cap part is sleeved with the illuminator part to form two mating surfaces (115, 125; 215, 225; 325; 515, 525; 803, 804).

4. The lighting device of claim 3, wherein:

the cap part and the illuminator part establish an electric connection when secured together; and

the mating surface (115) of the cap part faces inwardly and comprises an ohmic contacting pad (113, 114; 908, 909) for establishing said electric connection.

5. The lighting device of claim 3, wherein a plurality of parallel grooves (126; 426) are provided on at least one of the mating surfaces.

6. The lighting device of claim 5, wherein:

the illuminator part comprises a grooved translucent light diffuser for influencing the light distribution; and

the second end of the cap part is provided with a sleeve, the inside of which is provided with protrusions (416) adapted to engage with a portion of the translucent light diffuser to prevent azimuthal movement.

7. The lighting device of claim 1, wherein the cap part and the illuminator part engage in an axially locking fashion in each position.

8. The lighting device of claim 7, wherein the cap part comprises an axially locking element (124; 603) and the illuminator part comprises a reciprocal axially locking element (114; 604), said locking elements being engageable in at least two different orientations of the parts.

9. The lighting device of claim 8, wherein one axial locking element is a rib, ridge or groove (114; 604) extending in the azimuthal direction, and the other locking element is resilient in the radial direction.

10. The lighting device of claim 9, wherein one locking element is a groove comprising a recessed ohmic contacting pad (114).

11. The lighting device of claim 1, further comprising a marker (430, 431) for indicating a relative orientation of the cap part with respect to the illuminator part.

12. The lighting device of claim 1, wherein the illuminator part (1020) is securable to the cap part (1010a) at a first end (1022) and to a further cap part (1010b) at a second end (1023), the illuminator part and the further cap part being securable in at least two positions defining distinct relative orientations of the parts.

13. The lighting device of claim 1, wherein the illuminator part is tube- shaped and comprises a plurality of light-emitting diodes (LEDs).

14. An illuminator part (120; 220; 320; 420; 920; 1020) of substantially cylindrical shape, operable to provide an azimuthally uneven light distribution and engageable to a cap part (110; 210; 310; 410; 910; 1010) acting as an adapter vis-a-vis a socket (190; 290; 390),

wherein said illuminator part is securable to the cap part in at least two positions with distinct relative orientations, wherein the parts engage in an azimuthally form-locking fashion in both positions.

15. A cap part (110; 210; 310; 410; 910; 1010) engageable, at a first end (111; 1022), to a socket (190; 290; 390) and, at a second end (112; 1023), to an illuminator part (120; 220; 320; 420; 920; 1020) having substantially cylindrical shape and being operable to provide an azimuthally uneven light distribution,

wherein said cap part is securable to the illuminator part in at least two positions with distinct relative orientations, wherein the parts engage in an azimuthally form-locking fashion in both positions.