T 0676/04 20-09-2006

1. Admissibility of the Patent Proprietor's Appeal

It is clear from the minutes that the opposition division had carefully monitored requests submitted during the oral proceedings, and in particular, requests were confirmed by the parties before the decision was announced (see the minutes page 8, paragraph 7.15). Consequently, the set of claims which forms the basis of the contested decision was indeed the main request of the patentee. This has also been admitted by the attorney of the patent proprietor, but he maintains that the circumstances surrounding the filing of the request led to the proprietor being adversely affected in the sense of Article 107 EPC.

As far as the Board is concerned, there is no hint of anything untoward occurring during the oral proceedings. The opposition division expressed its opinion that claim 1 of a particular request lacked inventive step, but such an indication is normal judicial practice and is often given during hearings; it cannot be considered as subjecting the attorney to improper pressure to withdraw the request. The Board does not accept the argument of the proprietor's attorney that he was wrongly pressurised by the opposition division into withdrawing the request; it is assumed that attorneys practising before the EPO have a knowledge of the procedure for filing and withdrawing requests.

Since the proprietor is not adversely affected in the sense of Article 107 EPC, the appeal is deemed to be inadmissible. The proprietor is nevertheless a party to the appeal proceedings as of right.

2. Reformatio in Peius - Main Request and First and Second Auxiliary Requests

Since the proprietor's appeal is deemed to be inadmissible, the opponent becomes the sole appellant. Under the doctrine of no reformatio in peius, as expounded in decisions G 9/92 and G 4/93 (see OJ 1994, 875), if the opponent is the sole appellant, the proprietor is primarily restricted in appeal proceedings to defending the patent as maintained by the opposition division. The exception referred to in G 1/99 (OJ 2001, 381), allowing amendments to meet an objection put forward by the opponent/appellant or the Board during the appeal proceedings, does not apply here.

Claim 1 according to the main request and the first and second auxiliary requests does not contain the feature of granted dependant claim 2, this being a part of claim 1 as maintained by the opposition division, and is thus broader in scope than that maintained by the opposition division. Consequently, these requests fall foul of the doctrine and are not admitted into the proceedings.

3. Third Auxiliary Request

3.1 Article 100(c) EPC

As compared with claim 1 of the application as originally filed, claims 1 of the granted patent and of the third auxiliary request have been amended to define the anechoic member as being hollow. The opponent maintains that a hollow anechoic member is only disclosed in the patent application in combination with a strip of sound absorptive material on its base. Failure to define such a strip in claim 1 leads to an extension of subject-matter beyond the application as filed.

At page 8, lines 8 to 10 of the patent application it is stated that "However, as further shown in Fig. 2A, a layer of sound absorptive material 28 may be disposed on base member 29." (emphasis added). Normally the use of the word "may" is a clear indication that a feature is optional. However, as the opponent has indicated, the application is liberally sprinkled with "mays", also in connection with essential features (see for example page 8, lines 1 to 2), such that the usual linguistic meaning cannot be ascribed to this word. It is therefore necessary to determine which features the skilled person reading the application as a whole would understand as essential and which as optional.

It is clear that the patent application is directed to a protective covering for anechoic elements that provides a high degree of sound absorption (see page 3, line 23 to page 4, line 24). Claim 1 of the application as originally filed did not require that the anechoic wedge element be hollow, indeed according to one embodiment of the invention (see page 5, lines 32 to 34) it is foreseen that the entire interior space of the wedge can be filled with sound absorbing material. Thus according to the patent application, the feature of the wedge being hollow is an optional one. The question is whether the skilled person would understand that the embodiment relating to a hollow anechoic element must inevitably also include a layer of sound absorptive material on its base.

The role of the sound absorptive layer in hollow elements is to provide some additional absorbing capability, and to enable the anechoic element to be tuned to particular frequencies of sound (see page 8, lines 16 to 19 of the application). There will be situations where the sound absorbing capacity of the walls of the element is sufficient, and situations where tuning is not required; thus a hollow element is not inextricably linked to the necessity to have a sound absorbing strip. In addition, the functions of the sound absorbing strip have nothing to do with the main thrust of the invention, which is to provide a protective covering for anechoic elements.

A skilled person reading the application would therefore be of the view that the invention is directed to a covering, and whether or not the anechoic element is hollow or contains an extra strip of sound absorbing material is merely an option depending on the particular use the anechoic element is put to. Consequently, the amendment does not add subject-matter contrary to Article 123(2) EPC.

3.2 Articles 123(3) and 84 EPC

Given the arguments presented by the parties, it is convenient to consider the objections raised by the opponent under these two articles together.

Claim 1 of the granted patent defines a protective covering comprising a "substantially solid, sound reflective, protective cover sheet (20,50,60,70,80) having perforations therein". Claim 1 of the third auxiliary request refers to a "substantially solid, protective cover sheet (20,50,60,70,80) made of sound reflective material having perforations therein".

The opponent holds the view that claim 1 of the granted patent requires the cover sheet to be able to reflect at least some sound. This implies an upper limit to the area of perforations, since above about 50%, the cover would be incapable of reflecting any sound. By removing this limitation in claim 1 of the third auxiliary request, the opponent alleges that the scope of the claim has been extended, contrary to Article 123(3) EPC, to include covers that are fully sound absorbing.

The opponent is also of the view that in addition to Article 123(3) EPC, the above amendment is contrary to Article 84 EPC. In particular, the expression "sound reflective material" lacks clarity. Whether or not an object is "sound reflective" depends not only on the material, but also on the form it takes, so for example, a highly perforated metal sheet ceases to be sound reflective; hence, there is a lack of clarity as to what is meant by "sound reflective material".

In response to these grounds of objections, the proprietor argued that the two expressions, in granted claim 1 and amended claim 1, are synonymous, and thus there is no broadening in scope of the claim. The intention of the patent is to make the cover from a sheet of material provided with holes in order to enable it to absorb sound; this is readily apparent to the skilled person reading claim 1 in light of the specification.

The Board can find no indication in the description that the sound absorbing unit should be capable of reflecting sound at all; on the contrary, the invention is directed to a sound absorbing unit for an anechoic chamber, i.e. having an absorption coefficient of 0.99, and which thus should be capable of absorbing as much sound as possible. Paragraphs [0030], [0039] and claims 11 to 13 of the specification describe the types of material for the cover and the amount of perforations required for it to have a sound absorption coefficient suitable for anechoic conditions. The conclusion is that the skilled person would not read into either the granted or amended claim any requirement for sound to be reflected. Consequently, there is no infringement of either Article 123(3) or Article 84 EPC.

3.3 Novelty (Article 54 EPC)

In assessing novelty of the subject-matter of claim 1 with respect to E1, the opponent has interpreted a wall of the unit of E1 (feature 10 in Figure 6) as being the flat panel member of claim 1, and argues that Figure 6 shows walls 10 that are spaced apart from neighbouring units. This does not seem to be a reasonable interpretation, as a wall of a unit of E1 cannot be equated to the flat panel member of claim 1. Figure 6 of E1 shows an embodiment in which a plurality of sound absorbing units are suspended in an array, whereas Figure 1 shows an individual unit. It can be seen that there is no separate panel positioned at a distance from the unit in the sense of the disputed patent (see Figures 2A, 2B, 5A-5D); it is clear to the skilled person reading the patent specification that the anechoic element and the flat panel member are separate items. Alternatively, the base of the unit shown in Figure 1 of E1 equates to the flat panel of claim 1, in which case it is not spaced apart from the anechoic unit.

It is therefore concluded that the subject-matter of claim 1 differs from E1, at least in that the anechoic element is not spaced from the flat panel member, and hence the claimed subject matter is novel over E1.

3.4 Inventive Step (Article 56 EPC)

The opponent contests inventive step on the basis of the combination of either E3 or E10 together with either E12 or E13.

The invention set out in the contested patent relates to the provision of protective covers for sound absorbing units used in anechoic chambers.

E10 discloses sound absorbing elements for use on walls, ceilings etc., and in particular for use in an anechoic chamber (see page 1, lines 1 to 5 "laboratoires d'expériences acoustiques"). A row (1) of sound absorbing elements is positioned at a distance from base plate (3) (see Figures 1 and 3), and the elements have a protective cover of silk (see page 4, lines 19 to 21). E10 therefore forms an appropriate starting point for the invention, with subject-matter of claim 1 differing from that disclosed in E10 in that the elements have a perforated cover made of sound reflective material, rather than the silk covers of E10.

Starting from E10, the objective problem to be solved is seen as how to provide improved protection for the sound absorbing elements.

The opponent argues that the solution of providing a perforated cover, for example of metal, is obvious in light of either E12 or E13, both of which teach that sound absorbing material can be protected, whilst maintaining the sound absorbing property, by covering it with a perforated plate of hard material. In particular, E12 explains that, because sound absorbing materials tend to be mechanically soft, a protective cover is necessary (page 157, penultimate paragraph). Covers made from metal, board or plaster are completely transparent to sound if they are provided with at least 15% perforations (see paragraph bridging pages 157 and 158). E13 also discloses perforated covers for protecting sound absorbing units (see section 6.4.1), and teaches that sound waves can pass unhindered through the cover if the area proportion of holes is at least 30%. In the view of the opponent, it would be therefore be obvious to replace the silk covers of E10 by hard ones as described in E12 or E13, and given that E12 and E13 are extracts from text books, such a measure is merely within the general knowledge of the skilled person.

The proprietor argues that the purpose of the claimed sound absorbing unit is to provide a chamber with anechoic properties, i.e. absorption of 99% of the sound. Such sound absorbing units are to be distinguished from sound diffraction units, which operate under less strict requirements.

Regarding E12, the proprietor submits that the document does not relate to anechoic chambers, as evidenced by the relatively thin layer (about 4 cm) of sound absorbing material and the fact that it only has 50% absorption (see second and third paragraphs on page 157). Although the proprietor agrees that E12 discloses the use of a protective cover, and the cover is said to be completely permeable to sound, this is only in the context of the sound absorbing structure described in E12. The skilled person would have considered that such a cover would nevertheless have some detrimental effect when used in an anechoic chamber, where the standards are significantly higher, and consequently would not have entertained the idea.

Concerning E13, the proprietor refers to Figure 6/15, which shows that the maximum degree of absorption is less than 0.90, indicating that the material of E13 is not suitable for use in an anechoic chamber.

The proprietor also drew attention to E17, a document submitted by the opponent. Figure 140 concerns a sound absorbing panel having an absorption coefficient of 0.5 to 0.7 and shows a construction with a protective cover of perforated material. Figure 141, on the other hand, concerns a sound absorber with a coefficient of 0.98, and no protective cover is indicated. The proprietor argues that, especially as Figures 140 and 141 are side by side in the book, this is an indication that it is counter intuitive to provide high efficiency sound absorbers with a protective cover.

The Board is persuaded by the arguments of the proprietor that the sound absorbing capability of units for anechoic chambers is more demanding than for other applications. Whereas documents E12, E13 and E17 all show perforated covers for units having a sound absorbing coefficient up to 0.8, and this may be seen as general knowledge as suggested by the opponent, there is no indication that such a cover would be suitable for applications requiring a coefficient in the region of 0.99. Consequently, the skilled person would not immediately consider using a cover such as described in E12 or E13 for the sound absorbing elements of E10.

Even if it were considered that it is generally known that sound absorbing units made from delicate materials can be protected with a perforated cover of hard material, and the skilled person would be tempted to try such a cover for the elements of E10, it is doubtful that he would derive the subject-matter of claim 1. E12 discloses a sheet of perforated material as a cover, but which should not be placed in direct contact with the sound absorbing elements (see page 158, "Abdeckungen mit gelochten Platten sollten möglichst nicht unmittelbar vor der Schluckstoffschicht angeordnet werden"). Applying this teaching to E10, the obvious place for such a sheet in the structure of E10 would be as a flat plate above the metallic grid (5) shown in Figures 1 and 3; this would comply with the teaching of E12 and would provide a flat surface that is easy to maintain. However, claim 1 requires the walls of the anechoic members themselves to be covered with the perforated material, as shown in the Figures. Given that this is a more complex solution than simply providing a flat sheet over all of the elements, it is not be an obvious measure for the skilled person.

Similarly with E13, firstly, the document does not disclose material that the skilled person would seriously contemplate for use in an anechoic chamber, and secondly, even if it were to be used to protect the sound absorbing elements, the skilled person would not consider covering the wall of each individual element.

The subject-matter of claim 1 of the third auxiliary request therefore has an inventive step in light of E10 combined with either E12 or E13.

E3 describes sound absorbing elements for use in an anechoic chambers. The elements have as a protective covering a bag, made from, for example, nylon. The subject-matter of claim 1 differs from that of E3 at least in terms of the material and the form of the protective covering, and therefore is inventive for the same reasons as given above starting from E10.