T 1163/23 28-01-2025

I. The patent proprietor filed an appeal against the interlocutory decision of the opposition division on the version in which European patent No. 3297816 ("the patent") can be maintained.

II. The opposition division was of the opinion that the subject-matter of claim 1 of the patent as granted was not new over the prior art, and that auxiliary request 1 was not clear. However, auxiliary request 2 was found to comply with the requirements of the EPC.

III. Of the documents considered by the opposition division, the following were relevant to the appeal.

D5 DE 10 2013 223 567 A1

D9 Extract from John F. Ready, "LIA Handbook of Laser

Materials Processing", Laser Institute of America,

Magnolia Publishing, Inc., 2001

D10 Extract from John C. Ion, "Laser Processing of

Engineering Materials", Elsevier, Amsterdam, 2005

With its reply to the statement of grounds of appeal, the respondent filed the following further document.

D44 "Firestar ti-Series Operator's Manual" published

by Synrad in November 2013.

IV. Oral proceedings before the board were held on 28 January 2025. At the end of the oral proceedings, the appellant withdrew its main request and auxiliary requests 1, 3 and 4.

V. The appellant (patent proprietor) requested that the decision under appeal be set aside and that the patent be maintained as amended on the basis of the claims of auxiliary request 2, which had been filed with its statement of grounds of appeal.

VI. The respondent (opponent) requested that the appeal be dismissed. It also requested that auxiliary request 2 not be admitted. In the event that auxiliary request 2 was admitted, document D44 should also be admitted.

VII. Independent claim 1 of auxiliary request 2 reads as follows (the feature references used by the board have been inserted in square brackets; additions with respect to claim 1 as granted are underlined).

"1. [1] Method of marking a rubber article (102), the method comprising:

[2] generating a recess pattern (122, 222, 322, 422, 522) in the rubber article (102) [2.2] by removal of rubber material, [3] the recess pattern (122, 222, 322, 422, 522) defining a digital code pattern, wherein [3.1] said removal of rubber material is performed with an electromagnetic radiation beam, wherein

[3.2] the radiation beam is a laser beam (112) and wherein

[3.3] the 1/e² beam width of the radiation beam is larger than 200 µm;

[4] the digital code pattern comprising an array of code modules (150);

[5] the digital code pattern being a binary code pattern of which the code modules (150) represent either a digital "0" or a digital "1";

[6] the recess pattern (122, 222, 322, 422, 522) comprising a first recess portion (124) and a second recess portion (126), the first and second recess portions being recessed with respect to an unaltered surface of the rubber article;

[7] the recess pattern (122, 222, 322, 422, 522) defining code modules with relatively low reflectivity, wherein a code module comprising a recess portion (122, 124) represents a code module with relatively low reflectivity compared to a code module with a relatively high reflectivity having no recess portion;

[8] the first recess portion (124) and the second recess portion (126) defining therebetween a protrusion (130) protruding over a bottom (132, 134) of each recess portion;

wherein [9a] a pitch (136) between the first recess portion and the second recess portion is larger than 0.5 mm; or

wherein [9b] the first recess portion (124) and the second recess portion (126) are part of a recess (152) surrounding the protrusion and the protrusion (130) has a base area of more than 0.2 square millimeters;

[10] the method further comprising generating at least one of the first recess portion (124) and the second recess portion (126) with an aspect ratio between 0.2 and 2, wherein the aspect ratio is defined as the depth of the recess portion over the width of the recess portion."

Unlike the set of claims of the patent as granted, auxiliary request 2 contains no product claims.

NB: Claim 1 of former auxiliary request 2, which the oppo­sition division found to comply with the requirements of the EPC, differs from claim 1 of current auxiliary request 2 in that in feature 3.2 the laser was required to be a carbon dioxide laser (feature 3.2'), and in that the following additional features were included: "wherein [11a] the Rayleigh length of the radiation beam is larger than 1.5 millimeters; and [11b] the method comprising adjusting the focus position of the radiation beam in the direction of the radiation beam during generating the digital code pattern".

VIII. The parties' submissions concerning the issues that proved relevant for the outcome of the appeal may be summarised as follows.

(a) Admittance of auxiliary request 2

(i) Respondent

Auxiliary request 2 should not be admitted. The features of claim 2 as granted, which are now intro­duced into claim 1, were considered in the opposition proceedings from the very beginning. Claim 2 as granted comprises multiple alternatives, all of which are known from the prior art. In the opposition proceedings, the appellant chose to make all the features of claim 2 mandatory because this approach made it the most diffi­cult for the respondent to show that the claim was not patentable. Broadening the scope on appeal after a very thorough examination of the case by the opposition division (the oral proceedings lasted for two days) cannot be considered a response to a surprising out­come. The appellant has already filed over 15 requests during the opposition proceedings. It could also have filed what is now auxiliary request 2 within the time limit offered by the opposition division to file requests.

(ii) Appellant

Auxiliary request 2 was filed in response to the

opposition division's change of mind regarding the novelty of the former main request over document D5, and to its justification in the written decision. The oppo­sition division allowed the appellant to file one auxiliary request. As the detailed reasons for the dismissal of the main request were not at that point known, the appellant had the impression that it was best to move forward by combining claims 1 and 2. Even then, the appellant considered that the large laser beam was not suitable for obtaining the small structures disclosed in document D5. However, as the opposition division's reasoning was unknown, amending the claim only in this respect seemed risky. The argu­ments that were received with the written decision are unconvincing, and this triggered auxiliary request 2. The 15 auxiliary requests mentioned by the respondent were filed in response to the numerous objections raised by the respondent and to the opposition division's provisional opinion.

(b) Claim interpretation

(i) Appellant

To determine the meaning of "recess portion", the whole of claim 1 needs to be taken into account. The recess portions are part of a recess pattern. The recess pattern "defines", i.e. determines, code modules with low reflectivity. This is not just a structural but also a functional feature. A code module comprising a recess portion "represents", i.e. embodies, a code module with low reflectivity. In Fig. 3 of the patent,

the dashed lines 148 are edges of code modules. Paragraph [0085] of the patent states that they are logical edges. A recess pattern is engraved in the rubber article. The software recognises the arrange­ment of portions of high|FORMULA/TABLE/GRAPHIC|

and low reflectivity and identifies the code. The structure of the code module does not have to corres­pond one-to-one to one recess portion. As stated in paragraph [0060] of the patent, recess portions can overlap. In this case the protrusion formed between the recess portions is lowered with respect to the surface of the rubber article. This has nothing to do with the change in reflectivity.

(ii) Respondent

Claim 1 defines different structural and logical entities: there are structural elements (recesses and protrusions) that provide the logical entities (digital code pattern, code modules, binary code). The structu­ral limitations of the recess portions consist in the recesses with respect to an unaltered surface. Code modules with recesses have lower reflectivity than a code module without recesses. The claim leaves open whether the code module is completely constituted by a recess portion or whether the recess portion is just a part of the code module; both are covered by claim 1.

(c) Inventive step of the subject-matter of claim 1 in view of document D5 and the skilled person's common general knowledge

(i) Appellant

Document D5 discloses a surface profile on the bottom of the structures shown in Figs. 6 to 9. It discloses several possible ways in which the low reflectivity can be obtained. In Fig. 4 of document D5, the entire surface structure is lowered with respect to the surface of the rubber article. This has no impact on the reflectivity. The latter is determined by the structure on the bottom of the code module. The slopes have a sub-structure shown in Fig. 5 with steps having a height of 20 mym, far smaller than the claimed sizes. Until the present invention, it was assumed that small structural elements were needed to obtain the low reflectivity.

According to the second sentence of paragraph [0056] of document D5, the surface profile 3 of cell 6 is designed to absorb more light than the surface profile 3 of|FORMULA/TABLE/GRAPHIC|

cell 7. Each cell corresponds to a code module. It is not the amount of recess but the surface profile 6 and its step structure (see Fig. 5) that are responsible for the reduced reflectivity. The recess portion to be taken into account is delimited by the upper line, used to define the height 14. Thus, the pitch referred to in claim 1 is the distance between two neighbouring tips 9. Paragraph [0053] of document D5 discloses that this distance is equal to 0.24 mm, which is less than the pitch required by feature 9a (0.5 mm). Feature 9b is not disclosed either. A cell 6 is not a recess portion as claimed. Moreover, the free space between the parallel ridges of adjacent code modules of Fig. 4 of document D5 does not extend along the code modules (or even surround a white code module): it necessarily extends parallel to the ridges. Document D5 does not anticipate the idea of the invention but is contrary to it, because in document D5 the effect is obtained with small structural elements, whereas in the patent large structural elements with low reflectivity are used. Document D5 does not disclose direct engraving of the rubber article. The embodiment of Figs. 6 to 9 is distinct from the one of Figs. 1 to 5. Even for the former, there is no disclosure of engraving a rubber article. The German expression "bzw." in para­graph [0058] can mean "or" or "more specifically". The skilled person would have understood it to have only the latter meaning. They would have realised that the vertical resolution needed (0.2 mm / 256 = 0.78 mym) could not be obtained by direct engraving of a rubber article, but that it could be achieved by engraving the mould. Document D5 cannot be assumed to present the option of direct engraving in the context of an embodiment where it cannot be used. When looking for a method to implement the embodiment of Fig. 4, the skilled person would have used the general teaching given in paragraph [0041] of document D5, which does not refer to direct engraving of the rubber article.

Document D9 is too specific and complete to be considered the expression of the skilled person's common general knowledge. The dimensions of the surface profile elements dis­closed in document D5 are very small: they are in the micrometre range. As mentioned above, the distance between the tips 9 is 0.24 mm. It is specifically the structure that results in the low reflectivity. Even if considering document D9, the skilled person would not have envisaged the use of a beam with a 1/e² beam width larger than 200 µm for providing such fine surface structures. Document D9 establishes that it was known to use large beam sizes, but that disclosure is given in the context of writing characters that are readable by a person and have a height of 2 to 20 mm (D9, p. 526). The skilled person would not have used such a laser when implementing document D5, not even for the embodiment of Fig. 4, because the elements 8 have a triangular cross-section and a fine step struc­ture (see Fig. 5), which is disclosed as advantageous in paragraph [0027]. Contrary to the respondent's assertion, the very wording of features 3.1 to 3.3 excludes any focusing of the beam: the rubber material is removed with the beam, of which the width is specified.

(ii) Respondent

Document D5 has the same objective as the patent (see

its paragraph [0007]) and achieves this effect by similar means. The way in which different reflectivity values are achieved is disclosed in paragraph [0025]. Paragraph [0032] explains that it is advantageous if the surface profile of a cell matches the surface profile of the product. Para­graph [0051] describes the QR code of Fig. 2. Cell 6 has recesses in relation to the surface of the product. Thus, there are two types of cells with different reflectivity due to their engraved structure. It is incorrect to associate the deepest point 9 in Fig. 4 with the recess portion of claim 1. The entire cell 6 is recessed with respect to the unaltered surface, and constitutes the recess portion. Paragraph [0051] discloses that the corres­ponding pitch is 0.69 mm. Feature 9a is fulfilled. According to the second sentence of para­graph [0056], the reflectivity of the recess portion is reduced with respect to the reflectivity of the unaltered surface, and this is because of the structure (see paragraph [0025]). The description of Figs. 3 to 5 does not disclose how these structures are to be manufactured. The skilled person trying to implement Fig. 5 would have continued reading. The embodiment of Figs. 6 to 9 employs the same concept. Paragraph [0058] discloses that a surface profile 3 of this kind, or the complementary surface profile of a moulding tool for producing a surface profile 3 of this kind on a product surface 1, can be created by laser engraving. The expression "bzw." should not be read as meaning "in particular". Laser engraving of rubber was well known to the skilled person at the priority date (see documents D9, D10). On page 180 of document D9 it is disclosed that removal of rubber results in a roughening of the surface finish. Thus, the skilled person knew that the product surface's reflectivity could be modified in this way. The skilled person would have understood this teaching to apply directly to the embodiment of Fig. 4 of document D5. At the very least, the skilled person would have taken it into account when seeking a way to implement the embodiment of Fig. 4. The argument that the skilled person would have understood that direct engraving of the rubber material was not possible in view of the sub-micron dimensions of the structures to be obtained is true for the embodi­ments of Figs. 6 to 9, but not for the embodiment of Fig. 4. Laser engraving can be used to obtain these much coarser structures. The skilled person would have understood that the idealised structure of Fig. 4 was probably not achievable in practice but that the desired effect could be obtained even with a non-perfect structure. The sub-structure of Fig. 5 is not mandatory. Also, there is no upper limit to the laser beam size in claim 1, so its size cannot be an argument in favour of inventive step.

In regard of the problem-solution approach, and in particular of the technical effect of features 3.1 to 3.3, paragraph [0046] of the patent states that it "facilitates providing a suitable laser beam for per­forming the method". No technical effect is associated with these features. Features 3.1 to 3.3 do not mention a CO2 laser but only a laser beam having a certain size. Document D9 does represent the skilled person's common general knowledge in the field of laser engraving. It is mentioned throughout document D9 that the decisive step is the choice of the laser source; see in particular p. 459 of document D9, which deals with the cutting of nonmetals with Nd:YAG lasers. It mentions the problem that many organic materials are transparent to Nd:YAG laser light, or at least have a low absorption coefficient. By contrast, document D9 explains that CO2 lasers are well suited to the engraving of rubber. This would have led the skilled person to use such lasers. The skilled person would have realised that in the embodiment of Fig. 4 of docu­ment D5, the edge structure has an edge length of 0.69 mm (see paragraph [0051]). The structure shown in Fig. 3 of document D5 can be obtained with a 200 mym laser beam. The triangular shape does not have to be exactly reproduced: rounded shapes, cylinder shapes etc. are for example possible. There is no need to have a perfect structure. Incidentally, it is not even clear from the claim wording that focusing of the beam is excluded (see also, in the patent, paragraph [0074], where the beam width is 400 mym, and paragraph [0088], according to which a single module has a lateral size of 517 mym).

The person skilled in the art would also have considered document D44, an operator's manual for the material-machining CO2 laser series Firestar by Synrad. The laser is suitable for engraving operations, as disclosed on p. 39 of document D44. Some laser parameters for Firestar ti60 are summarised in table 3-7 on p. 330 of document D44. The beam waist diameter at 1/e**(2) is indicated, with the values for all wave­lengths lying well above the claimed limit of 200 mym. Therefore, the person skilled in the art would also have arrived at the subject-matter of claim 1 when considering document D5 in combination with document D44.