The invention relates to a discharge lamp, in particular a fluorescent lamp. The invention also relates to an assembly of a fitting and at least one discharge lamp according to the invention.

Discharge lamps, and in particular fluorescent lamps, have been known for several decades and are used in several applications. The lamps are among other applications widely used in lighting of indoor and outdoor areas. Discharge lamps have colour temperatures that vary over the entire spectrum, but these lamps are found to be relatively appealing due to the high efficiency of these lamps. That is, discharge lamps produce commonly between 80 and 100 lumens per watt compared to the conventional incandescent lamps which commonly merely produce about between 10 and 20 lumens per watt.

Moreover, it is noted that a conventional discharge lamp, in particular a fluorescent lamp (like TL24), commonly achieves an operation temperature of about 80 degrees Celsius in open luminary, while a conventional (100 watt) incandescent lamp commonly achieves a considerable higher operation temperature of about 200 degrees Celsius. Both the improved light output and the relatively low operation temperature of discharge lamps make these lamps highly suitable to be applied in several lighting applications. However, the application of known discharge lamps is limited to lighting purposes only, while there is increasing need to expand the functionality of the conventional discharge lamps.

It is an object of the invention to provide a multifunctional discharge lamp in a relatively easy and efficient manner.

The object according to the invention can be achieved by providing a discharge lamp according to the preamble, comprising: an at least partially light-transmissive discharge vessel filled with an ionisable substance, multiple electrodes connected to said vessel, between which electrodes a discharge extends during lamp operation, and means for releasing an active substance during lamp operation. By applying a means for releasing an active substance, the discharge lamp is given an additional functionality, wherein besides application of the discharge lamp as light source, the discharge lamp can be used also for other purposes due to the released active substance. Preferably, said active substance comprises at least one of the following substances: an aromatic substance, a disinfectant, a

deodorant and an insecticide. The aromatic substance is preferably formed by a scent, in particular a pleasant of savoury smell of perfume. It has been found that the use of smellable aromatic substances emotionally affects persons in a relatively efficient manner, wherein a smell stimulus may be more than 75% more efficient than other stimuli, like e.g. a visual stimulus like logo's and an auditive stimulus. For this reason, it may be relatively advantageously for commercial organizations to release a dosed amount of active substance, in particular a scent, to support economic activities, in particular vending activities, of these commercial organizations. As mentioned afore the active substance may also be applied for other purposes, such as exterminating or keeping away of insects, neutralizing or for disinfecting particular spaces. Preferably, the active substance is substantially merely released after exceeding a certain critical temperature, said critical temperature being situated above room temperature. In this way release of the active substance can be avoided, are at least counteracted, at lower temperatures like room temperature when the discharge lamp is not in operation. In that case, merely during lamp operation an observable amount of active substance will be released by the discharge lamp according to the invention. A discharge lamp is ideally suitable to allow a controlled and long- lasting release of active substance due to the relatively low operation temperature of the discharge lamp (about 80 degrees Celsius for normal fluorescent lamps). Application of an incandescent lamp provided with the means for releasing the active substance would not result in the desired effect of controlled and long- lasting release of the active substance. Due to the relatively high operation temperature of about 200 degrees Celsius of the incandescent lamp the active substance will be released uncontrollable and too quickly, which would lead to an undesirable situation like a very short scent life time. Moreover, in that case additional technical and expensive provisions should be taken to avoid burning, disintegrating or scorching of the active substance. For this reason, it has been found that controlled, dosed, and long- lasting release of the active substance could merely be achieved by applying a discharge lamp, in particular a fluorescent lamp. Different kind of discharge lamps could be used, provided that the operation temperature of these discharge lamps remains relatively low. Preferably, a fluorescent lamp, but also a compact fluorescent lamp, can be used as discharge lamp according to the invention. Fluorescent lamps are relatively durable, and are relatively cost effective and efficient, in particular during application of these lamps in areas where lights are on for long periods of time like public spaces and offices. It is also a common trend that more and more incandescent lamps are being replaced by compact fluorescent lamps due to their increasing performance and price reduction.

The means for releasing the active substance can be of various natures. It is conceivable to apply the active substance as (part of) a coating onto the discharge vessel and/or the electrodes, or by impregnating at least a part of the known fluorescent lamp with the active substance. Though, it is more preferable that the means for releasing an active substance comprises at least one carrier for holding said active substance. Preferably, the discharge lamp comprises multiple carriers, which may be positioned at opposite sides of the discharge lamp. The carrier may be integrated with the discharge vessel.

However, in another preferred embodiment said carrier is releasably connected to the discharge vessel. In this manner the carrier can easily be replaced by another carrier in case all the active substance has been released from the carrier and/or in case of damage to the carrier. The dimensioning, geometry and material selection of the carrier can be of various natures. However, the carrier is preferably designed such that the carrier is able to contain sufficient active substance for long- lasting release, and that the carrier is adapted to release the active substance dosed and in a controlled manner. Preferably, the carrier partially encloses the discharge vessel to increase the contact surface between the vessel and the carrier, and hence the heat absorption by the carrier used for the evaporation of the active substance. To avoid a decrease in effective light output of the discharge lamp due to partial covering of the light-transmissive part of the discharge vessel, said carrier is preferably positioned against an end surface of the discharge vessel. To this end, said carrier is preferably provided with at least one aperture for containing an electrode at least partially. In this manner, the carrier is positioned relatively efficiently and can be locked easily by the discharge lamp cooperating with a lamp fitting. In a preferred embodiment said carrier is at least partially porously. The pores of the carrier are adapted to contain the active substance. By varying the amount, geometry, and dimensioning of the pores the amount of active substance and duration of release of said active substance can be regulated. To this end, the carrier can be made of paper, plastic, foam and/or sponge-like material.

Commonly, said carrier is disposable and will be removed from the discharge vessel and thrown away when substantially all active substance has been released to an atmosphere surrounding said lamp. However, in an alternative embodiment it is also conceivable to apply a durable carrier with logo, which is adapted for multiple uses. After release of (a part of) the active substance the carrier can be refilled by the same (or another) active substance. It is thus imaginable that the discharge lamp according to the invention comprises multiple active substances, eventually multiple active substances with mutual different purposes. By using a translucent carrier the amount of scent substance that is left

can be made visible and by using different active substances with corresponding colours, or carriers of different colours, visual distinction can be made between different scents (e.g. yellow for a fresh lemon smell, blue for lavender smell, et cetera).

The invention also relates to a carrier provided with an active substance for use in a discharge lamp according to the invention. The, commonly disposable, carrier is adapted to be coupled releasably to a discharge vessel. In a preferred embodiment said carrier is contained within a removable sealed package. Said package may be adapted to contain multiple carriers according to the invention simultaneously.

The invention further relates to an assembly of a lamp fitting and at least one discharge lamp according to the invention connected to said fitting. Preferably, the means for releasing the active substance comprises a carrier for holding said active substance, said carrier being substantially locked by the interengagement of the fitting and the discharge lamp.

The invention can further be illustrated by way of the following non- limitative embodiments, wherein:

Figure Ia shows an exploded perspective view of a first embodiment of a fluorescent lamp according to the invention, Figure Ib shows a perspective view of the fluorescent lamp according to figure Ia in an assembled state,

Figure Ic shows a perspective view of an assembly of a lamp fitting and the fluorescent lamp according to figures Ia and Ib,

Figure 2a shows an exploded perspective view of a first embodiment of a fluorescent lamp according to the invention in an assembled state,

Figure 2b shows a perspective view of the fluorescent lamp according to figure 2a, and

Figure 2c shows a perspective view of an assembly of a lamp fitting and the fluorescent lamp according to figures 2a and 2b.

Figure Ia shows an exploded perspective view of a first embodiment of a fluorescent lamp 1 according to the invention. The fluorescent lamp 1 comprises a transparent elongated envelope 2 in which an ionisable substance is present. Two opposite

sides of said envelope 2 are connected with electrodes 3, of which merely one electrode 3 is shown. Said electrodes 3 are adapted for generating a discharge arc within said envelope 2 thereby generating light. The lamp 1 further comprises a scent disc or pad 4 provided with an active substance, preferably a perfume-based product, which disc 4 is adapted for controllable release of said active substance. This active substance may be formed by a natural substance. However, alternatively a synthetic substance is used, which may simulate a natural product or which may result in a new scent. However, modern perfumes, which may act as active substance, comprise blends of natural and synthetic scents and of fixatives which equalize vaporization and enhance pungency. In most liquid scents the ingredients are combined with alcohol. The scent disc 4 can be made out of various materials like: (porous) plastic, hard paper or cotton. The scent disc 4 is preferably not made of an electrical conductive material to avert a short circuit. Preferably, the scent disc 4 is designed such that observable release of active substance will merely occur at increased temperature, more preferably at operation temperature (about 80 degrees Celsius). The scent disc 4 is provided with two apertures 5 thereby forming a passage for two pins 6 making part of one of the electrodes 3. Figure Ib shows a perspective view of the fluorescent lamp 1 according to figure Ia. In this figure it is shown clearly that the scent disc 4 is situated against an end surface of the electrode 3, wherein the pins 6 of the electrode 3 run trough the apertures 5 of the scent disc 4 to achieve a stable positioning of the scent disc 4 with respect to the electrode 3.

Figure Ic shows a perspective view of an assembly 7 of a lamp fitting 8 and the fluorescent lamp 1 according to figures Ia and Ib. The pins 6 of the electrode cooperate with the lamp fitting 8 in the shown embodiment. Due to this interengagement of the lamp fitting 8 and the fluorescent lamp 1 the scent disc 4 is substantially kept in position. Since it is preferred not to change the (known) lamp fitting 8 and (known) electrodes 3 and envelope 2 constructively, the scent disc 4 is preferably relatively thin, and has preferably a thickness of up to about 3 millimetres.

Figure 2a shows a perspective view of a first embodiment of a fluorescent lamp 9 according to the invention in a disassembled state. The lamp 9 comprises an elongated transmissive discharge vessel 10 thereby enclosing a discharge space. The discharge vessel 10 comprises two electrodes 11 of which merely a single electrode 11 is shown. Each electrode 11 thereby comprises two terminal pins 12 for connecting said lamp 9 to a fitting (see figure 2c). The lamp 9 further comprises two hollow tube shaped scent caps 13, of which merely one cap 13 is shown, said cap 13 being provided or filled with a perfume to be

released at increased temperature, preferably operation temperature. The cap 13 is provided with multiple apertures 14 for receiving the terminal pins 12 respectively. According to figure 2b each cap 13 encloses an electrode 11 and covers a part of the transmissive part of the discharge vessel 10. In the assembled state as shown in figure 2b, the terminal pins 12 are fed trough the apertures 14 of the cap 13. The perfume can be released using an adaptive vent and/or refill hole 17. An outer surface 18 of the cap 13 is used for presentation of information, in particular a logo. The scent cap 13 can be made of different kinds of materials, such as e.g. metal, glass or hard paper but more preferably plastic. A production process for said cap 13 will most probably be (stretch) blow or injection moulding although other methods could be found appropriate as well.

Figure 2c shows a perspective view of an assembly 15 of a lamp fitting 16 and the fluorescent lamp 9 according to figures 2a and 2b. In the assembled state of the assembly 15, the scent cap 13 is locked by the interengagement of the lamp fitting 16 and the fluorescent lamp 9. Further advantages of applying a scent containing element in discharge lamps are already elucidated above in a comprehensive manner.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.