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Title:
TUBULAR DEVICE FOR FITTING TO A TUBULAR LIGHT FITTING
Document Type and Number:
WIPO Patent Application WO/2017/102559
Kind Code:
A1
Abstract:
A tubular lighting device comprises a tubular housing (12) having an elongate axis and first and second opposite ends, each end comprising two projecting electrical connection pins (16). A switch arrangement (60) is used to electrically isolate the projecting electrical connection pins of one end from the electrical connection pins of the other end. This provides a safety feature when fitting the lighting device to a luminaire. The tubular housing comprises a recess (20) in which an actuator surface (50) is provided for actuating the switch arrangement such that the actuator surface is internal of the outer envelope of the tubular housing. The actuator surface is for actuation by a key (42) inserted into the recess. A key is thus inserted to activate the lighting device. This reduces the risk of accidental activation.

Inventors:
ACKERMANN, Bernd (5656 AE Eindhoven, 5656 AE, NL)
HATTRUP, Christian (5656 AE Eindhoven, 5656 AE, NL)
JANS, William, Peter, Mechtildis, Marie (5656 AE Eindhoven, 5656 AE, NL)
SAUERLÄNDER, Georg (5656 AE Eindhoven, 5656 AE, NL)
Application Number:
EP2016/080322
Publication Date:
June 22, 2017
Filing Date:
December 08, 2016
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
PHILIPS LIGHTING HOLDING B.V. (High Tech Campus 45, 5656 AE Eindhoven, 5656 AE, NL)
International Classes:
F21V25/04; F21K9/272; F21V15/00; F21Y115/10
Domestic Patent References:
WO2012004708A22012-01-12
WO2009067074A12009-05-28
WO2009067074A12009-05-28
Foreign References:
NL2002333C2010-06-17
GB2506682A2014-04-09
CN204114660U2015-01-21
DE202008015047U12010-04-15
Attorney, Agent or Firm:
VERWEIJ, Petronella, Danielle et al. (High Tech Campus 45, 5656 AE Eindhoven, 5656 AE, NL)
Download PDF:
Claims:
CLAIMS:

1. A tubular lighting device for fitting in a luminaire, comprising:

a tubular housing (12) having an elongate axis and first and second opposite ends, each end comprising two projecting electrical connection pins (16); and

a switch arrangement (60) for electrically isolating the projecting electrical connection pins of one end from the electrical connection pins of the other end,

wherein the tubular housing comprises a recess (20) in which an actuator surface (50) is provided for actuating the switch arrangement, the actuation surface comprising a set of push buttons or a set of conductive tracks, such that the actuator surface is internal of the outer envelope of the tubular housing, wherein the recess is exposed when the ends of the tubular housing are fitted to a luminaire, and wherein the actuator surface is for actuation by a key (42) inserted into the recess,

wherein when the actuator surface comprises a set of push buttons, to actuate the switch arrangement, a first sub-set of the push buttons are to be pushed in, and a second sub-set of the push buttons are not to be pushed in; or

wherein when the actuator surface comprises a set of conductive tracks, to actuate the switch arrangement, a predefined interconnection between the conductive tracks is provided.

2. A device as claimed in claim 1, comprising an end cap at each end of the tubular housing, wherein the electrical connection pins project parallel with the tubular housing elongate axis, spaced apart on each side of a central axis (15) of the end cap (14).

3. A device as claimed in claim 1 or 2, wherein the recess comprises a bore or a slot.

4. A device as claimed in claim 3, wherein the recess extends fully diagonally through the tubular housing.

5. A device as claimed in claim 1, wherein each push button controls an associated electrical switch, wherein the first sub-set of push buttons each close their associated electrical switch when pushed in and the second sub-set of push buttons each open their associated electrical switch when pushed in, wherein the electrical switches are electrically in series. 6. A device as claimed in claim 5, wherein the push buttons are spring biased outwardly into a projecting configuration and may be pushed into a retracted configuration.

7. A device as claimed in any preceding claim, further comprising the key for insertion into the recess, wherein the key comprises a generally planar actuation surface with a series of indentations, wherein there are at least two different depths of indentation, one depth functioning as an actuation portion and another depth functioning as a non-actuation portion.

8. A device as claimed in claim 1, further comprising the key for insertion into the recess, wherein the key comprises a generally flat actuation surface with a conducting track arrangement.

9. A device as claimed in any preceding claim, wherein the switch arrangement is further for selecting between different modes of operation of the tubular lighting device.

10. A method of fitting a tubular lighting device to a luminaire, comprising:

fitting projecting electrical connection pins at one end of a tubular housing

(12) of the tubular lighting device to one end of a luminaire;

fitting projecting electrical connection pins at the other end of the tubular housing (12) of the tubular lighting device to the other end of the luminaire;

inserting a key (42) into an exposed recess (20) of the tubular housing, in which recess an actuator surface is provided, thereby actuating a switch arrangement to switch from isolating the projecting electrical connection pins of one end from the electrical connection pins of the other end to connecting the electrical connection pins of one end with the electrical connection pins of the other end, wherein the actuator surface is internal of the outer envelope of the tubular housing.

11. A method as claimed in claim 10, wherein inserting the key comprises actuating a set of push buttons, by pushing in a first sub-set of the push buttons and not pushing in a second sub-set of the push buttons. 12. A method as claimed in claim 10, wherein inserting the key comprises forming a predetermined interconnection between conductive tracks of the actuator surface.

13. A method as claimed in any one of claims 10 to 12, further comprising selecting between different modes of operation of the tubular lighting device by selecting the key to insert.

Description:
Tubular device for fitting to a tubular light fitting

FIELD OF THE INVENTION

This invention relates to tubular light fittings, and in particular to the tubular lighting devices which are received in such fittings. BACKGROUND OF THE INVENTION

Solid state lighting (SSL) is rapidly becoming the norm in many lighting applications. This is because SSL elements such as light emitting diodes (LEDs) can exhibit superior lifetime and energy consumption, as well as enabling controllable light output color, intensity, beam spread and/or lighting direction.

Tubular lighting devices are widely used in commercial lighting applications, such as for office lighting, for retail environments, in corridors, in hotels, etc. A conventional tubular light fitting has a socket connector at each end for making mechanical and electrical connection to connection pins at each end of a tubular light. Conventional tubular lights are in the form of fluorescent light tubes. There is a huge installed base of luminaires equipped with electronic ballasts for fluorescent tube lamps.

There are now tubular LED ("TLED") lamps which can be used as a direct replacement for traditional fluorescent light tubes. In this way, the advantages of solid state lighting can be obtained without the expense of changing existing light fittings.

Inserting a TLED lamp into a luminaire is potentially dangerous since it is possible to touch the connection pins on one end of the lamp whilst the other end of the lamp is already inserted and in contact with a hazardous voltage.

A conventional fluorescent tubular lamp can be inserted into such a live mains fixture without any danger because the connection pins on either side of the lamp are electrically insulated from each other by the glass tube of the lamp and the gas inside it. An electrical contact between the two ends of the lamp is only established if the gas inside it is ignited and this is only possible after both ends of the lamp have been inserted into the luminaire. Taking the lamp out of the luminaire will immediately stop both the current flowing through it and the gas discharge in it and thus immediately re-establish electrical insulation between both ends of the lamp.

A typical TLED retrofit lamp contains LED PCBs and LED driver PCBs which offer little electrical insulation between the connection pins on both ends of the TLED. It may therefore be dangerous to insert such a TLED into a live mains fixture.

Various pin safety measures have been proposed to overcome this safety issue. These pin safety measures usually interrupt the electrical connection between both ends of the TLED by at least one switch that is only closed when both ends of the TLED are inserted into the luminaire.

Both electrical and mechanical pin safety mechanisms are known. In some electrical pin safety solutions, an electromagnetic relay is closed when both ends of the TLED are inserted into the lamp holders in the luminaire. Insertion of the TLED into the luminaire is detected and the electromagnetic relay is closed using currents and voltages originating from the electronic ballast. Issues related to electrical pin safety mechanisms are the compatibility with the large number of different types of electronic ballasts and the cost and reliability of electromagnetic relays.

In mechanical pin safety solutions, at each end of the TLED a switch is closed when pressing a button. Either the lamp holder will push the button when inserting the TLED into the luminaire or it needs to be pressed manually.

WO 2009/067074 discloses a mechanical pin safety solution in which buttons are present at the end of the TLED, and these buttons are depressed when the TLED is fitted to a luminaire.

The buttons used in mechanical pin safety solutions may be pressed accidentally when inserting the TLED into a luminaire and thereby the protection against electrical shock may be deactivated.

There is therefore a need for an improved system for providing protection when fitting a TLED to a luminaire. SUMMARY OF THE INVENTION

The invention is defined by the claims.

According to an aspect of the invention, there is provided a tubular lighting device, comprising: a tubular housing having an elongate axis and first and second opposite ends, each end comprising two projecting electrical connection pins; and

a switch arrangement for electrically isolating the projecting electrical connection pins of one end from the electrical connection pins of the other end,

wherein the tubular housing comprises a recess in which an actuator surface is provided for actuating the switch arrangement such that the actuator surface is internal of the outer envelope of the tubular housing, wherein the recess is exposed when the ends of the tubular housing are fitted to a luminaire, and wherein the actuator surface is for actuation by a key inserted into the recess.

This arrangement provides a recess for receiving a key which activates the lighting device by completing electrical connection between the pins at opposite ends of the device. By providing the actuation surface within a recess, it is less likely for the actuation to be carried out by accident. The recess is accessible when the lighting device is fitted to the luminaire, so that the step of activating the lighting device takes place only after the lighting device is fitted to the luminaire and not as part of the fitting procedure.

The invention provides a mechanical solution, in the sense that a physical key is inserted. However, the key may itself be an electrical component or a purely mechanical component. The key provides a single inventive concept, that is to say, both the purely mechanical key and the electrical key are for cooperating with corresponding features on the actuator surface. The mechanical key may have recesses that actuate certain switches or even subsets of switches located on the actuator surface. The electrical key may have conductive tracks that line up with conductive elements upon the actuator surface. When the key is inserted the conductive tracks complete the circuit and allow the lamp to be powered. It may prove advantageous to have a fusible element connected to one or more of the conductive elements on the actuator surface so that if someone tries to override the safety system by inserting a fully conductive item, for example a spoon or similar, then the fusible element will blow and protect the user.

An end cap is for example provided at each end of the tubular housing, wherein the electrical connection pins project parallel with the tubular housing elongate axis, spaced apart on each side of a central axis of the end cap. This defines the standard tubular lighting configuration.

The recess may comprise a bore or a slot. It preferably extends radially inwardly from an outer surface of the curved tubular part of the housing. In this way, the key is simply pushed in radially inwardly after the lighting device is fitted to a housing. The recess may extend fully through the tubular housing so that access to the recess is possible from opposite sides of the tubular housing. This means the key can be inserted even if the housing has two possible orientations 180 degrees apart.

In one set of examples, the actuator surface may comprise a set of push buttons, wherein to actuate the switch arrangement, a first sub-set of the push buttons are to be pushed in, and a second sub-set of the push buttons are not to be pushed in.

The key in this case may be purely mechanical. The push buttons are within the outer envelope of the tubular housing. These buttons have to be pressed to close or open switches, and they cannot be pressed accidentally. Inserting a key with an appropriate physical shape is then used to press a predetermined subset of buttons and not to press the other buttons.

Electrical connection between the two ends of the lighting device may in this example only be established when all switches are set to the correct state. This prevents misuse by inserting a different object with a shape similar to the required key.

Each push button may control an associated electrical switch, wherein the first sub-set of push buttons each close their associated electrical switch when pushed in and the second sub-set of push buttons each open their associated electrical switch when pushed in, wherein the electrical switches are electrically in series.

Electrical connection between the two ends of the lighting device is in this example only established when all switches are closed.

The push buttons are for example spring biased outwardly into a projecting configuration and may be pushed in, to a retracted configuration.

The device may further comprise the key for insertion into the recess. In this set of examples, the key may comprise a generally flat actuation surface with a series of indentations, wherein there are at least two different depths of indentation, one depth functioning as an actuation portion and another depth functioning as a non-actuation portion.

This provides a purely mechanical and therefore low cost key.

In another set of examples, the actuator surface comprises a set of conductive tracks, wherein to actuate the switch arrangement, a predefined interconnection between the conductive tracks is provided.

This provides a mechanical key but it forms part of the electrical circuit when inserted into the recess. This simplifies the hardware needed inside the lighting device by avoiding the need for mechanical switches. There may instead simply be static or else spring loaded contact terminals for contacting the key. The device may again further comprise the key for insertion into the recess. In this set of examples, the key comprises a generally planar actuation surface with a conducting track arrangement.

The switch arrangement may further be for selecting between different modes of operation of the tubular lighting device. In this way, different keys may be provided so that when the key is inserted, a mode of operation is also selected as well as activating the light. This may for example relate to different color outputs or different brightness settings.

Examples in accordance with another aspect of the invention provide a method of fitting a tubular lighting device to a luminaire, comprising:

fitting projecting electrical connection pins at one end of a tubular housing of the tubular lighting device to one end of a luminaire;

fitting projecting electrical connection pins at the other end of the tubular housing of the tubular lighting device to the other end of the luminaire;

inserting a key into an exposed recess of the tubular housing, in which recess an actuator surface is provided, thereby actuating a switch arrangement to switch from isolating the projecting electrical connection pins of one end from the electrical connection pins of the other end to connecting the electrical connection pins of one end with the electrical connection pins of the other end, wherein the actuator surface is internal of the outer envelope of the tubular housing.

This method enables the lighting device to be fully inserted into a luminaire before it is activated. By having the actuator surface recessed, the risk of accidental activation is reduced or eliminated.

Inserting the key may comprise actuating a set of push buttons, by pushing in a first sub-set of the push buttons and not pushing in a second sub-set of the push buttons. This means it is not possible to perform the required push button configuration with a flat surface, so that a correct key has to be used.

Inserting the key may instead comprise forming a predetermined interconnection between conductive tracks of the actuator surface.

The method may comprise selecting between different modes of operation of the tubular lighting device by selecting the key to insert.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention will now be described in detail with reference to the accompanying drawings, in which: Fig. 1 shows a basic known tubular LED lamp;

Figs. 2A-C show a first example of a TLED;

Figs. 3A-D show a second example of a TLED;

Figs. 4A-B show one example of a key used to activate the lamp of Figs. 2A-C or 3A-D;

Figs. 5A-C show a first known end connector design or a tubular lamp;

Figs. 6A-C show a second known end connector design or a tubular lamp; Figs. 7A-D show a third known end connector design or a tubular lamp; Figs. 8A-B show a fourth known end connector design or a tubular lamp; Figs. 9A-B show a fifth known end connector design or a tubular lamp;

Fig. 10 shows two alternative slot designs;

Figs. 11 A-C showsa key design which may be used to prevent fitting of a tubular lamp with the key already inserted;

Figs. 12A-B show how the key design of Figs. 1 1A-C is suitable for two end connector designs;

Figs. 13A-B show one possible design of an electrical switch; and

Fig. 14 shows in schematic form the circuitry inside the tubular LED lamp.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The invention provides a tubular lighting device which comprises a tubular housing having an elongate axis and first and second opposite ends, each end comprising two projecting electrical connection pins. A switch arrangement is used to electrically isolate the projecting electrical connection pins of one end from the electrical connection pins of the other end. This provides a safety feature when fitting the lighting device to a luminaire. The tubular housing comprises a recess in which an actuator surface is provided for actuating the switch arrangement such that the actuator surface is internal of the outer envelope of the tubular housing. The actuator surface is for actuation by a key inserted into the recess. A key is thus inserted to activate the lighting device. This reduces the risk of accidental activation.

Figure 1 shows a basic known tubular solid state lamp 10, comprising a tubular housing 12 having an end cap 14 at each end (only one is shown). The end cap 14 carries external connectors 16 in the form of two pins offset to each side from a central axis of the end cap 14, parallel to an elongate axis 15 of the tubular housing 12. The end cap 14 connects electrically to the internal driver board and the circuit board which mounts the solid state lighting elements, for example LEDs, inside the tubular housing 12. Figure 2 shows a first example of a lamp with a safety feature which enables a user to ensure that the exposed pins are safe when fitting the lamp to a luminaire. It again has a tubular housing 12 having an elongate axis and first and second opposite ends, only one end being shown.

The tubular housing 12 has a recess 20 which is designed to receive a key. In this example, the recess is in the form of a cylindrical bore extending through the tubular housing. Within the recess, there is an actuator surface. It may be a side wall of the channel formed by the recess. The recess may extend fully through the tubular lighting device, or else it may be a closed bore. In the latter case, the bottom of the recess may be an actuation surface.

When a key is inserted, a switch arrangement is actuated so that the pins of one end are connected to the pins of the other end. For example, at one end there may be a pair of live pins and at the other end a pair of neutral pins. In the case of a fluorescent lamp, between the pins of each end is a filament. The filaments are the electrodes for the gas discharge. They are connected with two pins because they can then be heated before igniting the gas discharge.

In the case of a tubular LED lamp, a filament emulation circuit is provided between the pins at each end. One node of the filament emulation circuit is connected to the LED driver. The driver thus has one connection to the end of the tubular lamp where the pins are live and another connection to the other end of the tubular lamp where the pins are neutral. The voltage between the two ends of the tubular light will be several hundred volts. The actual magnitude depends for example on the kind of lamp, details of the electronic ballast operation, and the operating conditions of the lamp.

In general, a tubular light is designed to be inserted with either rotational orientation and also in either end-to-end direction into the luminaire. The switch arrangement is at one end of the tubular LED lamp, before the filament emulation circuit and it can connect and disconnect both pins at that end independently. The switch arrangement can also be arranged after the filament emulation circuit, in which case it will connect and disconnect both pins at the end simultaneously.

The actuator surface within the recess is internal of the outer envelope of the tubular housing 12 so that there is no external actuator which may accidentally be pressed.

Figure 2A shows a perspective view, Figure 2B shows a side view and Figure 2C shows a view from above. In the example shown, the recess extends fully though the tubular housing 12. This means that the recess may be designed to be exposed to the underside of the luminaire with either of the two possible rotational orientations of the lighting device. It means that the actuation surface is formed by one or more side walls of the recess.

The recess opening can be circular as shown, or it can have any other shape.

The recess 20 is accessible when the lighting device is fully fitted to the luminaire. For this purpose it may be set back from the very end of the tubular housing.

Figure 3 shows a second example in which the recess is a slot 30 at one end of the tubular housing. Figure 3A shows a perspective view, Figure 3B shows a top view, Figure 3C shows a side view and Figure 3D shows an end view.

The slot 30 extends perpendicularly to the line between the two pins 16 and extends back from the end of the tubular housing. The slot extends fully through the tubular housing 12 so that again the recess is exposed to the underside of the luminaire with either of the two possible angular orientations of the lighting device. The actuation surface may be one or more side walls or the slot end wall (i.e. the slot face which is parallel to the end of the tubular housing).

The invention thus provides a mechanical solution, in the sense that a physical key is inserted. However, the key may itself be an electrical or a purely mechanical component.

A purely mechanical key design will first be explained.

The key in this set of examples is used to press one or more buttons of the actuation surface, for example a set of buttons to be pressed in a particular combination, to control the switch arrangement.

Figure 4A shows a recess 20 having a set of three buttons 40a, 40b, 40c. In one example, a key with an appropriate shape is needed to press only two of the buttons.

Figure 4 shows the key 42 inserted. It has a set of notches. There are small notches for the buttons 40a and 40c to push those buttons in and a large notch for the button 40b to allow it to project.

The key thus presses a predetermined subset of buttons 40a, 40c, and pressing these buttons moves a switch ON. The key does not press the other buttons (40b in this example) which are OFF when pressed.

A galvanic connection between the two ends of the TLED is only established when all buttons are in the ON state. This prevents misuse by inserting a different object with a shape similar to the appropriate key. The three switches associated with the three buttons are connected in series and to the two ends of the TLED lamp. Current can flow through the TLED lamp only if a key with the required shape is inserted into the recess. Inserting an object with straight edges into the recess would press the button in the middle and open the switch connected to it and thus interrupt the connection between the two ends of the TLED lamp.

In this example, the key has a series of recesses 44 on its outer surface.

If the key has a circular shape, the recesses may be rings around a generally circular cylinder. The key can then be inserted into the recess with any rotational orientation. The key and recess may instead have a shape which can only be inserted with one or a small number of orientations, for example a rectangle. In this case, there may be recesses on two opposite faces so that the key can be inserted in either of the two possible orientations.

The key may have an arrangement of recesses which is symmetrical about a mid-axis perpendicular to the insertion direction. This is the case for the design of Figure 4B. It means the key can be inserted from either end of the recess when the recess extends fully through the tubular housing, and can present the same arrangement of recesses to the actuation surface.

When a key is inserted into a slot 30 of the type shown in Figure 3, then one of its edges presses the button or buttons in the slot 30, most typically the end wall of the slot. When the actuation surface is the end wall of the slot, this requires the opposite edge of the key to be pressed against the lamp holder. The button or buttons will push away the key and the latter will fall out of the slot if the TLED lamp is not mounted in a luminaire.

The distance between the lamp holder and the end cap of the tubular LED is not well-defined. To tolerate slightly different distances between the two lamp holders at opposite ends of the luminaire, the width of the key (in the direction of the tubular lamp elongate axis) can be made to be variable such that it adapts itself to the distance between lamp holder and the surface of the slot 30, when the button or buttons are in the pressed position. This can be achieved by a spring mechanism inside the key.

For some types of lamp holder, care needs to be taken to ensure there is an available surface against which the key can press. In particular, some lamp holders comprise grooves into which the pins are slotted (and then rotated) as part of the connection procedure.

Figures 5 to 9 show five different lamp holder designs.

Figure 5 shows a so-called Type la lamp holder. The lamp is inserted into a vertical slot with the pins aligned vertically (Figure 5 A), then the lamp is rotated by 90 degrees (Figure 5B) around a static circular guide to the final position (Figure 5C). Figure 6 shows a so-called Type lb lamp holder. The lamp is inserted into a vertical slot with the pins aligned vertically (Figure 6A), then the lamp is rotated by 90 degrees (Figure 6B) driving with it a rotating locking piece, to the final position (Figure 6C).

Figure 7 shows a so-called Type II lamp holder. The lamp is inserted into an opening with the pins aligned vertically (Figure 7A and 7B). One pin is seated in a first well (Figure 7C) then the other pin is seated in a second well (Figure 7D) with the lamp having been rotated by 90 degrees during this process.

Figure 8 shows a so-called Type III lamp holder. The lamp is inserted into a pair of vertical slots with the pins aligned horizontally.

Figure 9 shows a so-called Type IV lamp holder. The lamp pins are inserted into sockets of the lamp holder in the pin length direction (rather than in the perpendicular direction as in Figures 5 to 8 above) with spring- loaded lamp holders.

As explained above, for the slot design of Figure 3, the key presses against an end face of the lamp holder. The surface available for pressing the key against the lamp holder will be larger for some types of lamp holder if the slot is not placed symmetrically between the pins. For example, the key will not have a large surface to press against for the design of Figure 5.

Figure 10 shows two possible examples of asymmetric design for the slot 30. In the top version, the slot 30 is perpendicular to the line between the two pins, but offset from the center. In the bottom version, the slot 30 is no longer perpendicular to the line between the two pins but in this example it does pass through the center of the end cap.

There is still a potential safety issue related to using a key inserted into a recess as a mechanical pin safety solution. Depending on the details of the geometries of the key and the lamp holders used in the luminaire, it may be possible to first insert the key into the recess and then insert the tubular LED lamp together with the already- inserted key into the luminaire.

This safety issue may be overcome firstly by using a key or recess design which can be fitted only with one orientation. For example, the recess may have an asymmetric cross section so that the key has to be inserted with a particular orientation. The shape of the key can be then be designed so that with the key already fitted, the push and twist insertion function for example of Figures 5 to 7, cannot be accomplished. For example, the recess may be a passageway as in Figure 2 but with a trapezoidal instead of a circular cross section. However, any non-rotationally symmetric shape may be used (i.e. with rotational symmetry of order 1). The recess shape then dictates the orientation of the key with respect to the tubular LED lamp when it is inserted into the recess.

The key is then designed such that it extends to the vicinity of the connection pins when inserted into the recess. In this way, it can function to block the LED lamp fitting procedure if the key is already present.

One example is shown in Figure 11.

Figure 11 A shows a perspective view of the key 42 inserted into the recess 20. As shown in the top and side views of Figure 1 IB, the key 42 has a first pin part 42a which fits into the recess 20, and a second pin part 42b which overhangs the end of the tubular LED. Note that a non-rotationally symmetrical opening shape is not required in this case, because the second pin part 42b in any case prevents the key being inserted the wrong way around. The recess may for example have a rectangular shape.

Figure 12 shows how this key design is effective for Type la (Figure 12 A) and Type II (Figure 12B) lamp holders. In both cases, the tubular LED cannot be fitted into the luminaire with the key already inserted, and the key can be inserted after the tubular LED is installed. In the two examples of Figure 12, it is also impossible to remove the tubular LED lamp from the luminaire before the key has been removed from the recess.

For the other designs shown above (Figures 6, 8 and 9), the design is safe in that the tubular LED cannot be inserted with the key in place, but a different design is needed to enable the key to be installed after the tubular LED is fitted. Thus, different designs may be needed for different lamp holder types, if the additional safety feature is desired. If the additional safety feature is not needed, a single design may function for all lamp holder types.

It is also possible to design the key in such a way that it extends towards the reflector or other parts of the luminaire if the key is inserted into the recess before the tubular LED lamp is inserted into the luminaire.

Figures 13 A and 13B show one possible design for the switches in the tubular housing, which have actuation parts projecting into the recess.

Figure 13A shows the open switch. The actuation surface is shown as 50. The switch has a button 52 which projects into the recess under the bias of a spring 54. In this configuration, electrical switch contacts 56 are separated.

Figure 13B shows the button 52 pushed back by the key 42 to close the switch contacts 56.

As an alternative to having a key with a mechanical shape, conductive connections may be provided on the key, which code a particular set of connections. The conductive tracks on the surface of the key form interconnections between terminals formed inside the recess. This provides additional safety against activating the TLED using a shaped piece of plastic or a folded piece of paper.

Using such conductive connections, the driver can also be programmed or set operating points can be defined. For example, different keys can be used to select between different brightness or other settings. Different keys may be marked with color codes, e.g. green = low light output, yellow = medium light output, red = high light output.

The key may combine the mechanical shape function and the electrical interconnection function. The key may also have electronic components in addition to or instead of simple conductive connections.

In use of the lighting device, the projecting electrical connection pins at one end of the tubular housing are fitted to one end of a luminaire and then the projecting electrical connection pins at the other end of the tubular housing of the tubular lighting device are fitted to the other end of the luminaire. Only then is the key inserted into the exposed recess of the tubular housing. The lighting device is fully inserted into a luminaire before it is activated. By having the actuator surface recessed, the risk of accidental activation is reduced or eliminated.

To remove a lamp from a luminaire, the key should of course be removed from the recess first.

Figure 14 shows the tubular LED lamp. The lamp has end caps 14 at each end, and the tubular housing 12 between. Within the tubular housing 12 there is an LED driver circuit 62 and an arrangement of LEDs 64 provided on a PCB arrangement 66 (which may have separate or a shared PCB for the driver circuitry and the LEDs).

The switching arrangement 60 is provided between the pins of one of (or both of) the end caps and the LED driver circuit 62. It connects or disconnects the associated pair of pins to the LED driver circuit 60, which in Figure 6 can be assumed to include the filament emulation circuits. The filament emulation circuits can also be included in the end caps 14. In this case, there will be only one connection between the end cap 14 and the switch arrangement 60, only one connection between the switch arrangement 60 and the LED driver circuit 62, and only one connection between the other end cap 14 and the LED driver circuit 62.

When the switch arrangement 60 is open, the pins at one end are isolated from the pins at the other end, so that even with one end connected to a luminaire fitting, the other end is still safe to touch, until the key 42 is inserted into the recess 20. The LEDs may be a strip of LEDs on the internal printed circuit board 66, or there may be discrete surface mount LEDs. The housing 12 has a transparent or partially transparent outer wall or outer wall portion. The driver circuit 62 provides a current-regulated output to the LED arrangement.

The mechanical key example above has three switches. This enables the activation to require some buttons to be pressed and some not to be pressed, and it also enables symmetry so that the required button selection is the same with either insertion direction of the key. There may be more buttons. Also, by combining a mechanical key with an electrical track interconnection approach, there may be only one button, since the risk of accidental activation is reduced such that the need for a special key shape is less important.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.