T 0032/10 12-01-2012

1. The appeal is admissible.

2. Admissibility of Documents D2 and D3

These documents were mentioned on the European search report drawn up during examination of the application for the disputed patent. They were cited by the appellant both in the grounds of opposition and the notice of appeal, but no indication was given of the relevance of these documents. D2 and D3 were also not considered by the opposition division in its decision.

In the letter dated 9 December 2011 the appellant stated that D2 and D3 provide evidence of the general knowledge in the art, but no reason was given for referring to these documents at such a late stage in the proceedings.

A document cited in the search report is not automatically in opposition or opposition appeal proceedings (see Case Law of the Boards of Appeal of the European Patent Office, 6th Edition, 2010, page 717, VII.C.1.7). Although the appellant had cited the documents with the grounds of appeal, their significance was not known until shortly before the oral proceedings in appeal. D2 and D3 are therefore considered as being filed late, and since their content could have been discussed earlier and there is no good reason for the late filing, they are not admitted into the proceedings.

3. Admissibility of the Evidence of Mr Schenk

3.1 The appellant put forward Mr Schenk as a witness to provide evidence of the knowledge of the skilled person.

3.2 Article 117(1) EPC provides examples of various means of giving evidence before the European Patent Office, and these include:

(d) hearing of witnesses;

(e) opinions by experts.

There is thus a distinction between the hearing of witnesses and the hearing of opinions by experts.

It has been established by the case law of the Boards of Appeal that a witness is put forward to establish facts of which he has personal knowledge. So, for example, in T 311/01 the offer of witness testimony on the skilled person's knowledge and understanding of a prior art document was refused, as this was not evidence of specific facts but of the knowledge and ideas of the skilled person. Likewise, in T 1511/06 the Board refused to hear a witness who had been offered, not to provide evidence of the circumstances of a specific non-disclosure agreement, but on the general practice of non-disclosure agreements between car and part manufacturers.

3.3 In the present case, Mr Schenk has been offered to provide evidence that the skilled person would be aware that, when bonding green components made of a powder and a binder, it is only the properties of the binder that are important. However, this evidence does not relate to a specific fact, but rather it is an opinion concerning the extent of knowledge of the skilled person. The appellant was therefore offering an expert opinion rather than a witness, and consequently the Board decided not to hear Mr Schenk as a witness.

3.4 Nevertheless an expert accompanying the professional representative may make submissions at the discretion of the Board, and the appellant requested that Mr Schenk be allowed to speak before the Board in this capacity. Criteria for exercising the discretion are set out in the decision of the Enlarged Board of Appeal G 4/95 (see the Headnote). Of particular relevance is that:

- the request should be made sufficiently in advance of the oral proceedings so that all opposing parties are able properly to prepare themselves in relation to the proposed oral proceedings; and

- a request which is made shortly before or at the oral proceedings should in the absence of exceptional circumstances be refused, unless each opposing party agrees to the making of the oral submissions requested.

3.5 In the present case oral proceedings were appointed for 12 January 2012 and the appellant offered submissions from Mr Schenk in the letter dated 9 December 2011, which was received at the European Patent Office on the 12 December 2011. Hence the request was made late, namely one month before the oral proceedings, and with the Christmas holiday taking place in that month.

The Board agrees with the submission of the respondent that the request was filed too late for an adequate response to be prepared, and also noted that for this reason the respondent did not agree at the oral proceedings to Mr Schenk making submissions.

In addition, the issue of the significance of the properties of the binder was already known during the opposition proceedings which means, given that Mr Schenk is an employee of the appellant, that the request could have been made much earlier in the proceedings.

3.6 Therefore the Board exercised its discretion not to allow Mr Schenk to make submissions during the oral proceedings. For the same reasons, the affidavit tendered by Mr Schenk with the letter of 9 December 2011 was also not admitted into the proceedings.

4. Clarity (Article 84 EPC)

4.1 Claim 1, as maintained by the opposition division and which formed the basis of the main request before the Board at the start of oral proceedings, was directed to a process for preparing a hermetically sealed hollow metal body.

The appellant raised the objection that there was a lack of clarity in the expression "hermetically sealed", since much of the disputed patent is directed to the manufacture of a fluid flow nozzle, which has inlet and outlet passages, meaning that it is not hermetically sealed.

4.2 The Board agreed with the submission of the appellant, as a lack of clarity arises from the discrepancy between the claims and the description. However, the objection was raised late, ie at the start of the oral proceedings, hence the Board saw fit to give the respondent an opportunity to amend its main request to define the body as being a "hermetically sealed hollow metal fluid flow nozzle".

The skilled person would realise that it is the joints between the component parts of the metal fluid flow nozzle that are hermetically sealed, and not the nozzle itself. This definition meets the requirements of Article 84 EPC.

5. Novelty (Article 54 EPC)

5.1 The appellant contests novelty on the basis of E1. This document discloses a process whereby complex shaped parts are moulded from a plurality of green compacts that are joined together. There is no explicit mention of making hollow bodies that are hermetically sealed, but according to the appellant these features are readily derivable from E1 by a skilled person using his general knowledge.

5.2 E1 merely refers to "complex shapes", but these need not necessarily be hollow. Whether or not the skilled person would understand that the reference to complex shapes is intended to include hollow parts is more appropriate to the assessment of inventive step. The test for lack of novelty is strict: the feature of a hollow body must be directly and unambiguously derivable from the statement that the shape is complex, and that is not the case.

5.3 Likewise, the statement that no line of demarcation between the original compacts can be observed in the final product does not inevitably mean that a hermetic seal exists. As submitted by the respondent, further defects may exist in the region of the joint that render the seal less than hermetic, but such defects may not be visible to the naked eye.

5.4 The appellant refers to D1 as evidence that the fact of no line of demarcation must mean a hermetically sealed joint. However, D1 makes it clear that there is both no line of demarcation between the parts joined by the process of D1 and that the joint is hermetically sealed. There is no teaching in D1 that lack of a visible indication of the joint inevitably means that there is a hermetic seal.

5.5 Consequently the claimed process is novel over E1.

6. Inventive Step (Article 56 EPC)

6.1 Claim 1 of the amended main request concerns the preparation of a hollow fluid flow nozzle by moulding metal powders into two component green parts which are joined together prior to sintering. Document E6 also describes a powder metallurgical process for making a hollow fluid flow nozzle, namely a tap, in which the halves of the tap are produced separately and then joined together during the sintering process. Both parties and the opposition division considered E6 as being the closest prior art, and the Board sees no reason to depart from this view.

6.2 The claimed process differs from that of E6 in that the green halves are ultrasonically welded together in a process using energy director surfaces prior to sintering, and this creates a joint that is hermetically sealed.

6.3 According to the patent specification (see paragraph [0003]) a process of the type described in E6 cannot reliably be used to obtain a hermetic seal. The respondent therefore sees the objective problem starting from E6 as providing a hermetic seal. The appellant formulates the problem as merely improving the quality of the joint. However, in the present case, there is no significant difference between the two definitions of the objective problem.

E6 combined with E2, E3 and E4

6.4 Starting from E6, the appellant submits that the solution is to be found in any one of the documents E2, E3 and E4. Document E2 describes joint designs for ultrasonic welding of polymers and resins. E3 discloses a method for ultrasonic welding of thermoplastic work pieces. E4 concerns a housing for a fuse, whereby the housing is made by ultrasonically welding together two parts made of thermoplastic material.

6.5 None of the documents E2, E3 or E4 relates to manufacture of parts by the powder metallurgy route, and it is for this reason that the opposition division recognised an inventive step. The appellant argues that in the context of ultrasonic welding it is the material properties of the binder that are important. Since the binder is usually a plastic material, the skilled person would consult E2, E3 and E4.

6.6 The skilled person is well aware that ultrasonic welding of plastic components is commonplace, however the question is whether there is any pointer in the prior art that the quality of the joint between two sintered parts can be improved by ultrasonically welding the green parts together. The disclosures of E2, E3 and E4 are limited to the bonding of plastics and give no indication of either the objective problem or its solution. Therefore the claimed process has an inventive step over this combination of documents.

E6 combined with D1

6.7 Document D1 is concerned with the end-capping of ceramic beta-alumina tubes that are used in sodium-sulphur batteries. The process of D1 achieves a hermetically sealed bond between the sintered parts and includes ultrasonically welding the caps to the tubes (column 1, lines 13 to 22).

6.8 A number of particular problems are identified in D1 that have to be overcome in order to create a hermetic bond between the cap and tube; these are set out in column 1, lines 32 to 54 and are summarised as follows:

- it is generally difficult to ultrasonically weld the thermoplastic elastomer binders used with beta-alumina ceramics;

- the inclusion of waxes and plasticisers in the binder interferes with its ability to transmit ultrasonic vibration energy;

- beta-alumina particles are of a hydroscopic nature and it would be expected that this would to lead to foaming at the joint interface;

- high loading of particles in the binder means that there may be insufficient binder for successful bonding.

These difficulties and the proposed solutions relate to the nature not just of the binder material, as submitted by the appellant, but also of the ceramic powders. There is no indication that the teachings of D1 are of broader relevance and could apply to metal-based sintered components, such as in E6. Of course, with knowledge of the disputed invention it seems obvious in light of D1 to at least try ultrasonic welding as a means of improving the joint, but assessment of inventive step must be made objectively without the benefit of hindsight.

6.9 According to D1, the tube is cut to give a smooth surface that is in contact with the cap before applying ultrasonic vibrations, hence the respondent argues that there is no teaching of the use of energy director surfaces. Energy directors are generally well known in the art for aiding ultrasonic welding (examples are given in E2, E3 and E4), but nevertheless the inventors of D1 did not consider them necessary for achieving a high quality bond. This is presumably because the size and shape of the tube and cap allow sufficient concentration of energy. D1 does not teach that energy directors should not be used, it is simply that they are not relevant for the components being joined in D1, and is a further indication of particular nature of the problem faced in D1.

6.10 In summary, given the particular material and geometric problems addressed in D1, the Board agrees with the respondent and the opposition division that the skilled person would not look to D1 for a solution to the objective problem.

E6 combined with E1

6.11 The appellant also submits that the claimed solution to the problem of improving the quality of the joint of E6 is provided by E1, which is directed to the formation of complex shaped objects by joining together component parts in the green state.

6.12 The green parts of E1 are provided with bumps and corresponding depressions for assisting alignment (column 1, lines 51 to 55), after which an electrical current is passed through the green parts to spot weld them together (column 1, lines 66 to 68). The respondent is correct in pointing out that ultrasonic welding is only mentioned in E1 as a supplement to enhance particle intermingling during spot welding (column 2, lines 7 to 8). The current density is greater in the region of the bumps, and this causes more heat to be generated and enhanced spot welding at these points (column 2, lines 8 to 15), but there is no indication in E1 that the bumps would function as the ribs or interfering portions of claim 1 to create a hermetically sealed bond.

6.13 It is significant that there is no discussion of the quality of the bond in E1, other than to say that no line of demarcation between the original parts is visible in the final product (column 3, lines 11 to 16). E1 is concerned with a completely different problem to that of the disputed patent, namely the manufacture of complex shaped parts, and there is no teaching of the link between the quality of the bond and ultrasonically welding the green components. The claimed process thus has an inventive step in light of E6 and E1.