T 0287/16 - Contradictory passages in affidavit

Key points

• In this opposition appeal, claim 1 is for a graphite sheet with two properties (thermal conductivity dispersion and roughness). The opponent alleges lack of novelty over a commercial product as prior use. There is no dispute that the graphite sheet was a public prior use, but opponent had measured the two properties only later. 
• "the opposition division raised doubts as to whether the properties of the tested graphite sheets which form the basis for the results of D6 and D7 were identical to those of the graphite sheets available prior to the priority date of the patent in suit" 
• The opponent then files an affidavit to declare " the manufacturing methods, [] have not changed to any material extent. In other words, no significant changes have occurred. (....)   the graphite sheets were created using the same method of manufacture".
• The Board is not  convinced : "the cited passages are contradictory or at least ambiguous. The first of the cited passages permits some (minor) changes in manufacturing methods as well as in the properties of the final expanded graphite sheet compared with the graphite sheets publicly available before the priority date. No further details about the nature and degree of such changes, apart from the subjective statement that they were "no[t] significant", are given. In contrast thereto, [the second passage] stresses that the same method of manufacture (as in the past) was used and that therefore the product had the same physical properties, although this was relativised in the next sentence by a reference to a (quantitatively undefined) margin of error. " 
• " Concerning document E6, this excerpt from a laboratory notebook contains a page dated 8 October 2006. A printed sheet seems to be glued onto that page, the printed sheet bearing a different date, i.e. 13 November 2006. The [opponent] has not provided a convincing reason as to why these two dates are different. " 

EPO T 0287/16 -  link


3.2 Prior use of HS-400

3.2.1 The opposition division found that the "HS-400 Heat Sink Material" having a thermal conductivity in a direction parallel to the surface of 370 W/mK and described in E5 was publicly available prior to the priority date of the patent in suit (see impugned decision, section 5). This finding is not contested.

3.2.2 The question that needs to be answered is whether HS-400 possessed all the features of claim 1 prior to the effective date of the patent in suit. In order to prove that HS-400 possessed surface roughness and thermal conductivity dispersion values falling within the claimed range, the appellant relies on E6 (surface roughness values) and E7 (Angstrom test).

[From the opponents arguments: " The prior use of HS-400 was also novelty-destroying. E6 and E7 showed the surface roughness and the thermal conductivity dispersion as required in claim 1. This was evidenced by E29. In view of E29, there was no need to rely on E25." ]

[...]

3.2.4 It is undisputed that the data in D6 and D7 [presumably: E6 and E7] were produced after the priority date of the patent in suit. In its decision, the opposition division raised doubts as to whether the properties of the tested graphite sheets which form the basis for the results of D6 and D7 were identical to those of the graphite sheets available prior to the priority date of the patent in suit (see item 5 of the appealed decision). As stated above, affidavit E29 was submitted by the appellant to overcome any doubts in this respect.

However, paragraph 7 of E29, referring to the method for (re-)producing the graphite sheets, contains the following passage (emphasis added by the board): "The wording [used in the previous affidavit] was intended to mean that the manufacturing methods, and therefore also the physical properties of the resulting graphite sheet, have not changed to any material extent. In other words, no significant changes have occurred ...".
Passage 9 of E29 goes on to state: "However, as the graphite sheets were created using the same method of manufacture, they will have the same physical properties. The results shown in E6 and E7 are therefore within the acceptable margin of error for the graphite sheet available before the priority date of the European patent number 1783097."

To the board, the cited passages are contradictory or at least ambiguous. The first of the cited passages permits some (minor) changes in manufacturing methods as well as in the properties of the final expanded graphite sheet compared with the graphite sheets publicly available before the priority date. No further details about the nature and degree of such changes, apart from the subjective statement that they were "no[t] significant", are given. In contrast thereto, passage 9 of E29 stresses that the same method of manufacture (as in the past) was used and that therefore the product had the same physical properties, although this was relativised in the next sentence by a reference to a (quantitatively undefined) margin of error. Thus, it cannot be concluded without any doubt from E29 alone that the graphite sheets available before the priority date and the ones used later on were produced by exactly the same process and that they were therefore, as far as technically possible, identical.

Taking into account the fact that the question of whether production methods and product properties had changed over time had already been an issue in the first instance proceedings and that E29 was submitted to clarify this question, the board comes to the conclusion that the doubts as to the identity of the physical properties of the various graphite sheets still exist. The affidavit presented leaves it open whether the manufacturing methods applied/products used were, as far as technically possible, identical. For this reason alone the prior use HS-400 cannot be regarded as novelty-destroying.

3.2.5 Furthermore, the tests according to D6 and D7 were carried out at different points in time (in 2005 and 2006), and in each case only one of the required properties was determined. No proof has been submitted that the graphites tested in D6 and D7 were identical and that the combination of all the requirements as defined in claim 1 (surface roughness and thermal conductivity dispersion values) was met in every case.

[...]

For these reasons too, the board is not convinced that the above data relate to a single sheet of graphite. Thus, the data provided fail to prove that the publicly available material HS-400 possessed the thermal conductivity dispersion called for in claim 1.

3.2.7 Concerning document E6, this excerpt from a laboratory notebook contains a page dated 8 October 2006. A printed sheet seems to be glued onto that page, the printed sheet bearing a different date, i.e. 13 November 2006. The appellant has not provided a convincing reason as to why these two dates are different. For this reason, too, the board is not convinced that the surface roughness data contained in E6 necessarily relate to HS-400 material in the form which was available to the public before the effective date of the patent in suit.

3.2.8 In conclusion, it has not been established that the material HS-400 which was publicly available before the effective date of the patent possessed the surface roughness values and thermal conductivity dispersion falling within the ranges of claim 1.

3.2.9 The subject-matter of claim 1 is therefore also novel in view of the publicly available material HS-400.

3.3 In conclusion, the ground for opposition set forth in Article 100(a) in conjunction with Articles 52(1) and 54(1),(2) EPC does not prejudice the maintenance of the patent.