The present invention relates to a filter for a smoking article. In particular, it relates to a smoking article filter through which smoke passes prior to inhalation by a user. Smoking article filters are, of course, well known.

It is also relatively well known to provide smoking articles with a filter and which contain one or more user-activated components.

The purpose of the user-activated component(s) is to allow a user to activate it when desired to alter the smoke during the smoking process. For example the component may be a capsule which is crushed by a user to add flavour to smoke during use of the smoking article.

Whilst such smoking articles are becoming popular amongst users, there can be a problem in that it is difficult for the user to know whether or not they have activated the component(s) sufficiently to provide the desired effect on the smoke.

According to the present invention there is provided a filter for a smoking article, the filter comprising filter material and a user-activated component for altering smoke passing through the filter, the filter further comprising an indicator component for cooperating with the user-activated component to indicate when the user has activated the user-activated component.

In the present invention, the term "cooperating" should be understood to imply a physical and/or chemical interaction between the indicator component of the tipping element with the user-activated component and/or its contents. Preferably, the cooperation between the indicator component of the tipping element with the user-activated component and/or its contents at least comprises fluid communication between the two features. In other examples, the cooperation between the indicator component of the tipping element with the user-activated component and/or its contents could comprise liquid communication between the two features, interaction of particles and/or compounds, any chemical contact, or any physical contact between items to induce a change in properties of one or the other of the items.

The user-activated component may be a flavour releasing means and may be in the form of a capsule or thread. The indicator component may be a thread. Further, the indicator component may be able to drive liquid released by the user-activated material faster or further than the rest of the filter material in at least one direction. Further, the indicator component may be pre-impregnated with an indicator material that is activated when the user activates the component. The activation of the indicator component may occur through wetting of the thread with liquid from the user-activated component.

The filter may be arranged such that activation occurs by a user applying pressure on the sides of the filter or by applying a radial twisting force to the filter.

The indicator component may be provided at least around a portion of the outer edge of the filter. Further, the indicator component may be provided at a proximal end of the filter adjacent to where a user places their mouth in use.

In some examples, the filter may comprise a liquid retaining means to prevent liquid that is driven through the thread or indicator component from coming out from the filter.

In some examples, the user-activated component may be surrounded by material prior to its insertion into the filter component, said material forming part of the indicator component.

The indicator component may be arranged to indicate the degree of activation of the user-activated component.

In some examples, the filter further comprises a plug wrap surrounding the filter material, and wherein the indicator component is formed on or in the plug wrap material.

With the filter of the present invention it is possible to provide to a user a clear indication that activation of the smoke altering user-activated component(s) has definitely occurred. This assists the user when activation has occurred, and also indicates when the smoke altering user-activated component(s) has been used so that a user does not try to activate it a second time.

According to the present invention there is also provided an indicator component for use in a filter according to the invention as described above, arranged to provide an indication to the user when a user-activated component associated therewith is activated in use. According to the present invention there is also provided a smoking article comprising the filter or the indicator component as described above.

An example of the present invention will now be described with reference to the accompanying drawings, in which:

- Figures 1A and B are side cross-sectional views of a smoking article employing a filter according to the present invention;

Figure 2 is a series of end views of the smoking article of Figure 1 showing the location of indicators;

Figures 3, 4A and 4B show further examples of indicator configurations according the present invention;

Figures 5A and 5B show examples of the present invention in which the indicator is prevented from extending all the way to the distal end;

Figure 6 shows an example filter of the present invention with liquid directing components;

- Figure 7 shows an example array of capsules in a filter- in accordance with the present invention; and

Figures 8A and 8B show an alternative pair of filter configurations- in accordance with the present invention.

Referring to Figure 1 , a smoking article 1 comprises a tobacco rod 2 and a filter 3. In use a smoking article 1 is lit at a free distal end 2a of the tobacco rod 2 and smoke is drawn from this distal free end 2a of the tobacco rod 2 through the filter 3 and onto a proximal end 3b of said filter 3 where it is inhaled by a user.

Usually the tobacco rod 2 will be surrounded by a wrapping 6, usually made of paper, which acts to retain the tobacco rod 2 in place and to direct the smoke towards the filter 3.

There will usually also be provided tipping material 4 which surrounds the filter 3 and extends over the wrapping 6 of the tobacco rod 2 to connect them together. The tipping material 4 retains a proximal connecting end 2b of the tobacco rod 2 and a distal connecting end 3a of the filter 3 in abutment against each other to provide structural integrity to the smoking article 1 and allow proper guiding of the smoke from the distal end 2a to the proximal end 3b of the smoking article 1. In these examples the filter 3 comprises a user-activated component 5 which, in this example, is in the form of a capsule 5 of the type disclosed in EP- A-1906775. In alternative examples, the user-activated component 5 may be in the form of multiple capsules or, alternatively, in the form of one or more threads or extruded components embedded within the filter material of the type described in WO-A-2001/058319, for example.

The user-activated component 5 may comprise a smoke altering component or substance, for example a flavour altering liquid which alters the flavour of the smoke when it is activated. If one or more threads are provided as the user-activated component 5 then these may be impregnated with a smoke altering liquid or other material. What all the possibilities have in common is, however, that the activation of the user-activated component 5 by a user either by compression, in which case the capsule is broken or the thread(s) release smoking altering material, or by twisting to provide a similar effect. If activation is achieved via twisting then the filter 3 may be provided by two components that can be twisted with respect to one another, the twisting applying a force to the user-activated component 5 in order to activate it.

As can be seen from Figures 1A and 1 B, the present invention also provides an indicator component 7 which indicates to the user when the user- activated component 5 has been activated. The indicator component 7 can for example be a single thread (Figure 1 A) or multiple threads (Figure 1 B).

In the example of Figure 1A the indicator component 7 takes the form of one thread which is impregnated with a colour or contrast-changing material or dye that is activated by the presence, preferably by contact of the smoke altering component released by activation of the user-activated component 5. As an alternative it may be activated by the same force application that activates the user-activated component 5. The thread is positioned so that it is visible to a user, in this case, by being positioned to extend to the proximal end 3b of the filter 3 where it is easily viewed by a user. Markings 8 may be provided on the exterior of the filter 3 to indicate the exact location of the user-activated component 5 and/or of the indicator component 7 to make it easy to view by a user.

In the example of Figure 1 B there are also threads as indicator component 7, but in this case the threads are made by extruding material within the filter and they are exposed only at the proximal end 3b of the filter 3 where a user normally places their mouth. A symmetrical shape is shown, and this may be preferable for ease of manufacture, although it is not essential. Of course, the extruded material may be replaced with multiple single threads as shown in Figure 1 A to produce a pattern formed from spots, for example.

In both of these examples, threads are shown as indicator component 7 but these threads could be replaced by components made from paper, non- woven fabric, hollow fibres or hollow tubes. In these cases it may be preferable, particularly if wetting of the indicator component 7 is used, to alter its appearance so that the indicator component 7 has a rapid capillary reaction when compared to the surrounding filter material such that the indicator component 7 is activated quickly and a clear visual indication is provided to a user as quickly as possible.

Figure 2 shows a number of proximal end front views of a filter 3 according to the present invention, each illustrating alternative indicator arrangements. In Figure 2A four examples of indicator components 7 are shown, each employing separate threads which extend to the proximal end 3b of the filter 3. They vary from a single hollow thread through to multiple solid threads.

Figure 2B shows a number of examples of shape indicator components 7, all of which are generally symmetrical for ease of manufacture, and all of which may or may not extend all the way to the proximal end 3b of the filter 3 as will be described below.

Figure 2C shows three examples of indicator components 7 in which planes of indicator material are formed within the filter 3. Again these planes may or may not be recessed.

Finally, figure 2D shows a number of corona type configurations of indicator components 7, of differing shapes, where filler material surrounds an outer indicator component that again is generally symmetrical, but may be a simple circle or oval or may have a more complex configuration.

Figure 3 to 5B shows examples of a filter 3 according to the invention where liquid retaining means is provided within the filter 3 to prevent liquid released by the user-activated component after activation being driven through the indicator component 7 and coming out from the filter 3. Figure 3 shows another example of the present invention in which a barrier layer 10 is provided over a central indicator component 7 to ensure that any smoke altering material from the user-activated component 5 is directed towards the proximal end 3b of the filter 3 as rapidly as possible. The barrier layer 10 may be a wax coating over the indicator component 7, or a plastic sheath or other sealed component.

Figure 4A shows a similar configuration for a corona-type structure, where an outer barrier layer of material 10 is provided beneath the tipping paper 4 to prevent liquid seeping to the tipping paper 4 and damaging it. Alternatively, the tipping paper 4 itself can act as an outer barrier layer to prevent the liquid seeping to the external surface of the tipping paper and wetting the user's fingers. The tipping paper 4 can also be at least partially translucent and thus contribute to the visual effect of the indicator component 7 on a side of the filter 3, not only at the proximal end 3b of it.

Figure 4B shows a side sectional view of a further configuration in which the filter 3 comprises a plug wrap 1 1 and the indicator component 7 is arranged within the plug wrap 1 1. In Figure 4B, the indicator component 7 is shown as a series of threads within the plug wrap 1 1 , but it will be appreciated that the plug wrap 1 1 could in itself be formed of a material that can provide the necessary indicator functionality, or the plug wrap 1 1 could be provided either with an external or internal surface formed from indicator material such that, after activation of the user-activated component 5, an indication is provided to a user as with other examples. In this example, the tipping paper 4 can also contribute to visualizing the indicator component 7 on a side of the plug wrap 1 1.

Figures 5A and 5B show configurations in which the indicator component

7 is recessed at the proximal end 3b of the filter 3, so that it does not completely reach to said proximal end 3b but is still apparent to the user and prevents liquid that is driven through the thread from coming out of the filter 3. In Figure 5A the indicator component 7 is recessed from the proximal end 3b, and in Figure 5B an end seal 12 is provided with the material which does not draw liquid through it, that material being, for example, wax or melted thread which seals the end, yet which still permits the user to observe a contrast or colour change in the thread of the indicator component 7. Figure 6 shows an alternative configuration of the filter 3 of the present invention in which the user-activated component 5 is a capsule 14 which is encased in thread 13 in a "sock" type configuration, such that, when it is activated, liquid is readily drawn into the thread to provide an indication. Figure 7 shows an array of capsules 14 that could be provided into a stream of filter material and then sliced to form individual filters according to the present invention. This "sock" type configuration may also help avoiding unintentional damage to the capsule 14 during its insertion into a filter at manufacture.

Figures 8A and 8B show an alternative configuration in which smoke altering material is retained within a user-activated component 5 that is in the form of a compressible bag 15 and has attached thereto one or more plugs or valves 16 which are activated by compression of the bag 15 that forces the smoke altering material out through the plugs or valves 16 to the indicator component 7, which is made of one or more threads for example. An optional filter component made of regular, well known, filter material may be included adjacent to the tobacco when the filter 3 is assembled in the smoking article 1.

In certain instances it may be desirable to provide an indicator component 7 which provides an indication of the degree of activation of the user-activated component 5. For example, user-activated components 5 are known which require not only activation, but then continued pressure application to dispense the smoke altering substance they contain. For example, the user may have to apply pressure over an extended period of time to dispense smoke altering substance, for instance liquid, from the user-activated component 5. In such a case the indicator component 7 may be configured to change contrast or colour dependent upon the amount of liquid that it receives from the user-activated component 5 to indicate in the extent of activation. Alternatively, if multiple indicator components 7 are used it may be that these are structured so that the number that are affected by activation of the user-activated component 5 is depended upon the extent to which the user-activated component 5 is activated.

In all these examples, the thread acting as an indicator component 7 may be configured so that it is able to draw any smoke altering substance that activates it rapidly to the surface where it can be viewed by a user. This ensures rapid indication of activation. With the configuration of the filter of the present invention it is possible to provide a filter 3 with a user-activated component 5 which alters a smoking experience yet still provides certainty to the user that activation has occurred on a simple and effective manner that is not dependent upon the component or material being used for altering that smoking experience.