T 1573/23 14-07-2025

I. The patent proprietor filed an appeal against the revocation of European patent No. 3 509 866 ("the patent") by the opposition division.

II. The opposition division was of the opinion that the ground for opposition under Article 100(c) EPC prejudiced the maintenance of the patent and that the sole auxiliary request did not comply with the requirements of Article 123(3) EPC.

III. On 10 January 2025 the board issued a communication pursuant to Article 15(1) RPBA.

IV. Oral proceedings before the board took place on 14 July 2025 by videoconference.

V. The appellant (patent proprietor) requested that the decision under appeal be set aside and that the patent be maintained as granted (main request), or that the decision under appeal be set aside and that the patent be maintained as amended on the basis of auxiliary request 1 decided upon in the decision under appeal or auxiliary request 2 filed with the statement of grounds of appeal.

VI. The respondent (opponent) requested that the appeal be dismissed. The respondent also requested that auxiliary request 2 not be admitted into the appeal proceedings.

VII. Independent claims 1 and 15 of the patent as granted read as follows (the feature references used by the oppo­sition division are added in square brackets):

"1. [A] A method of producing a security device (1), comprising:

[B] providing a substrate (10) having a relief structure (20) in or on its surface, the relief structure being provided in a first region of the substrate, [B1] the relief structure in the first region having a first recess or a plurality of first recesses (21) in or on the surface of the substrate, the first recess or recesses being recessed with respect to one or more corresponding first land areas (22) of the first region in or on the surface of the substrate; and

[C] applying a coating of a colour-shifting structure (30,40,50) to the relief structure [C1] such that the coating of the colour-shifting structure is received in the first recess or recesses of the first region and on the one or more first land areas and characterised in that [C2] a thickness (t) of the coating of the colour-shifting structure in the first recess or recesses is greater than or less than a thickness of the coating of the colour-shifting structure on the one or more first land areas."

"15. [A'] A security device (1) comprising:

[B'] a substrate (10) having a relief structure (21) in or on its surface, the relief structure being in a first region of the substrate;

[B1'] the relief structure in the first region having a first recess or a plurality of first recesses (21) in or on the surface of the substrate, the first recess or recesses being recessed with respect to one or more corresponding first land areas (22) in or on the surface of the substrate; and

[C'] a coating of a colour-shifting structure (30,40,50) [C1'] on the relief structure in the first recess or recesses and on the one or more first land areas; characterised in that [C2'] a thickness (t) of the coating of the colour-shifting structure in the first recess or recesses is greater than or less than a thickness of the coating of the colour-shifting structure on the one or more first land areas."

Claim 1 of auxiliary request 1 differs from claim 1 of the main request essentially in that the four occurrences of the words "coating of a/the colour-shifting structure" have been replaced with "colour-shifting coating structure".

Claim 15 of auxiliary request 1 differs from claim 15 of the main request essentially in that the three occurrences of the words "coating of a/the colour-shifting structure" have been replaced with "colour-shifting coating structure".

Auxiliary request 2 contains only one claim, which is identical to claim 15 of auxiliary request 1.

VIII. Terminology

For the sake of concision, the board uses the abbreviation CSS for "colour-shifting structure(s)".

IX. The parties argued as follows:

(a) Claim interpretation

(i) Appellant

Features C and C'

When considered in isolation, the expression "coating of a CSS" can have several meanings, namely (a) a coating consisting of a CSS, or (b) a colour-shifting coating structure, or (c) a coating of a CSS; however, when read in the context of the independent claims, it can only have the meaning of a coating consisting of a CSS or a colour-modifying structure. Interpretations (a) and (b) are equivalent in the present context. Interpreta­tion (c), which corresponds to interpre­ta­tion (i) of the opposition division, is incorrect because it disregards the grammatical and semantic structure of feature C. If the coating were applied to the CSS, then the feature would read "applying a coating to a CSS" instead of "applying a coating of a CSS". The coating is applied to the relief structure and not to a CSS. The sub-feature "of a CSS" expresses the nature of the coating. Only interpretations (a) or (b) are correct. According to the opposition division's inter­pretation (ii), the coating of the CSS is only a sub-layer (absorber, spacer, reflector) of this structure; how­ever, feature C relates to the coating of a CSS as a whole and not to a single sub-layer of that structure. Interpretation (ii) is contrary to the literal meaning of feature C. With regard to claim 15, it is clear from the context of features C', C1' and C2' that the colour-shifting coating is applied as a whole to the relief structure and that the coating is the colour-shifting coating rather than an additional layer.

The interpretation according to which a coated CSS is applied to the relief structure (see the last paragraph of point 6.1 of the board's communication) is not one that the skilled person would have envisaged. When relief structures are coated with a CSS, the coating is never present in a form that would allow it to be coated. The colour-shifting structure is generated in the applica­tion process. For instance, a reflector is vapour-deposited, then a spacer is deposited in liquid form and finally an absorber is vapour-deposited. There is nothing that could be coated before it is applied.

Page 33, lines 7 and 8, 10 to 15 or 26 to 31 of the application as filed establish a correspondence between a coating of a CSS and a colour-shifting coating.

The opposition division's assertion that the skilled person would not have considered paragraph [0008] of the patent when interpreting the claims is question­able. A patent can provide its own lexicon, and therefore the skilled person would always consider the description, also in the context of Article 123(2) EPC.

(ii) Respondent

It is clear from the construction and wording of the feature "coating of a/the CSS" that the proposed interpreta­tions (a) and (b) are not correct. The words "of a/the" indicate that this is not a layer consisting of a CSS. There is no reason to believe that the coating refers to the CSS as a whole. A comparison of the original feature and features C1 and C1' demon­strates that their technical meaning differs. Page 33, lines 26 to 31 of the application as filed refers to "a coating of CSS" and not "a coating of a CSS".

(b) Main request: added subject-matter

(i) Appellant

Features C and C'

The amendment does not generate subject-matter

extending beyond the content of the application as filed. A direct comparison of the original feature "(applying) a colour-shifting coating structure to the relief structure" and the feature "(applying) a coating of a CSS to the relief structure" demonstrates that, in both cases, the relief structure is provided with a coating of a CSS. If the features under consideration are not read in isolation but in the context of the other features to which they relate, both formulations have the same technical meaning. On page 33, lines 26 to 31 of the original description, the expression "coating of CSS" is used as a synonym for "colour-shifting coating" to describe a coating of a colour-tilting structure. The absence of the indefinite "a" is not relevant because the description is intended for the skilled person rather than for a linguist.

The respondent's assertion that "coating" can refer to any layer is wrong. If any layer was meant, the word "layer" would have been used. A "coating" always covers an existing object.

In point 8 of the board's communication, it was argued that the amendment that led to paragraph [0008] of the patent as granted violated Article 123(2) EPC. This cannot be true, if only for logical reasons. If alpha designates the feature "coating of a colour-shifting structure" and beta designates the feature "colour-shifting coating structure", the description now specifies that beta = alpha. The replacement of alpha with beta in the claim then cannot violate Article 123(2) EPC because the combination of claim 1 as granted and paragraph [0008] as amended corresponds exactly to what was originally disclosed. The situation would be different if claim 1 still had feature alpha because this feature could be given a different meaning. It seems question­able that it is at the board's discretion to raise the objection of its own motion. The appellant expressly does not give its consent for the new objection to be introduced. Article 125 EPC mentions principles of procedural law generally recognised in the Contracting States. Because the board is comparable to an administrative court, it should apply the principle of party dispo­si­tion (Antragsgrundsatz). The objection is not simply a new argument, but it invokes new facts, namely the wording of paragraph [0008].

The respondent's understanding of paragraph [0008] is flawed. It is self-evident to the skilled person that the expression in brackets explains the expression "coating of a colour-shifting structure".

Feature C2: "such"

The objection is linguistic and unrelated to what the

skilled person would have under­stood. During examina­tion, the term "such" was replaced with "characterised in" in feature C2. The opposition division concluded that the amended claim covers undisclosed embodiments in which the thickness of the colour-shifting coating is no longer the result of its application; however, it follows from features C and C1 that the colour-shifting coating is applied to the relief structure, both to the raised areas and in the recesses. The coating is achieved by its applica­tion. Its thickness according to feature C2 is a direct result of the application (see also the original claim 36; cf. claim 15 as granted). It is not apparent how the varying thickness of the coating could be technically achieved other than by applying the coating. Claims are to be interpreted in a techni­cally meaning­ful way and with the intention of under­standing them. The skilled person would not consider interpretations that make no techni­cal sense. It was not demonstrated that the layer thickness of the colour-shifting coating could be anything other than a result of the application of the colour-shifting layer. The amendment does not change the literal sense of claim 1 as filed. It only adapts the claim to become a two-part version. The arguments under point 2.2 of the decision under appeal are objections of lack of clarity rather than objections under Article 123(2) EPC.

It should be noted that the words "characterised in that" in claim 1 are preceded by the conjunction "and". Consequently, feature C2 is connected to features C and C1. Subliminally (unterschwellig), feature C2 is perceived as a process feature, but even if feature C2 expressed a mere result, it would have to be the result of the application step. It is unrealistic to consider that the skilled person would have envisaged reducing the applied layer by abrasion (Abschleifen).

(ii) Respondent

Features C and C'

The amendment from "colour-shifting coating struc­ture" to "coating of a/the CSS" modifies the technical meaning of the claim. In the application as filed, a colour-shifting (coating) structure designates a struc­ture consisting of several layers (reflector, absorber and optical spacer) causing a colour-shifting effect (page 1, lines 18 to 25; page 9, lines 13 to 21). The expression "colour-shifting coating struc­ture" has the meaning of a coating structure generating a colour-shifting effect. The expression "a coating of a/the CSS" has the meaning of a layer (coating) of the CSS itself or of an additional layer applied to it. The reference to page 33 of the application as filed is not helpful because the expression used in this passage is "coating of CSS" and not "coating of a CSS". The assertion that the coating may be the CSS itself is not reasonable in view of the wording of feature C ("... a coating of a CSS ..."). In the English language, "coating" (Beschichtung) can designate a mere layer (Schicht). Contrary to the original disclosure, it is not the CSS that has a varying layer thickness, but one of the layers of this structure. Therefore, the subject-matter of independent claims 1 and 15 of the patent includes undisclosed embodiments.

Paragraph [0008] of the patent must be read in light of the overall disclosure of the patent. It does not equate the expressions "coating of a CSS" and "colour-shifting coating structure", if only because the content of the brackets "(referred to as a "colour-shifting coating structure")" refers to the expression that immediately precedes it ("a CSS") rather than to "a coating of a CSS".

Feature C2: "such"

In claim 1 as filed, the feature corresponding to feature C2 is formulated in such a way that the different layer thickness is a consequence of the application step according to feature C. The different layer thickness is caused by the application of the layer (and not e.g. by a subsequent treatment). This is missing from claim 1 as granted. The insertion of the words "and characterised in that" has separated feature C2 from the preceding features. If the connection were to be maintained, the wording should have been "and characterised in that the coating is applied such that a thickness ...". Thus, the amendment does not meet the requirements of Article 123(2) EPC, and therefore the ground for opposition under Article 100(c) EPC prejudices the maintenance of the patent as granted.

It is possible to modify the thickness once the coating has been applied, not so much by abrasion but by solvent vaporisation or thermal processing, for instance.

(c) Auxiliary request 1

(i) Appellant

The oppo­sition division was wrong to consider that Article 69 EPC is not applicable when examining whether the requirements of Article 123(3) EPC are met. In paragraph [0008] of the patent, it is explicitly stated that "a coating of a CSS" is to be understood as a "colour-shifting coating structure" and that these terms are synonyms in the present context. In the light of the description, it is apparent to the skilled person that the amended claims cover exactly the same subject-matter as the claims as granted and that the amendment does not extend the protection conferred. It merely replaces one expression with another equivalent expression. Therefore, auxiliary request 1 meets the require­ments of Article 123(3) EPC.

Claim 1 of auxiliary request 1 restores the wording of claim 1 as originally filed. Consequently, there can be no violation of Article 123(2) EPC. The objection to paragraph [0008] of the patent was raised for the first time in the board's communication and was not raised by either the opposition division or the opponents, and is therefore not the subject of the contested decision. It should be rejected.

(ii) Respondent

The subject-matter of auxiliary request 1 does not meet

the requirements of Article 123(3) EPC. The features "a coating of a CSS" and "coating of the CSS" have a dif­fe­rent technical meaning. Replacing one with the other results in a change in the technical meaning of the inde­pen­dent claims. The question of the extent to which Article 69 EPC is applicable does not arise. The interpretation of the original claims must be based on the content of the application as filed, whereas the subject-matter of auxiliary request 1 is based on the amended claims and the corresponding description. If the expression "a colour-shifting coating structure" is interpreted such that it refers to the entire CSS comprising the absorber, spacer and reflector layers, Article 123(2) EPC is violated because of the different meaning of the corresponding features of auxiliary request 1 and the main request. Moreover, the objec­tions raised to feature C2 are not dispelled by the amendments made in auxiliary request 1.

The board's comment on paragraph [0008] of the patent does not constitute a new objection, if only because an objection under Article 123(2) EPC had already been raised to auxiliary request 1 by the respondent. The appellant's interpretation of this paragraph is flawed, as pointed out in the context of the main request.

(d) Auxiliary request 2: admittance

(i) Respondent

Auxiliary request 2 should not be admitted into the appeal proceedings. It was not examined in the first-instance proceedings and it is not prima facie suitable for overcoming the objections to auxiliary request 1. The patent proprietor's statement of grounds of appeal does not set out how auxiliary request 2 overcomes the objections to the main request and auxiliary request 1.

(ii) Appellant

The request is admissible. The patent proprietor only discovered in the Reasons for the decision under appeal that the opposition division had changed its opinion with regard to the replacement of "such that" with "characterised in that". Auxiliary request 2 was therefore filed on the earliest possible date.

(e) Auxiliary request 2: added subject-matter

(i) Respondent

In view of the board's conclusion that there are two possible interpretations, the skilled person might adopt either one of them. They would not have considered that both are being protected. For the skilled person adopting the view that the coating can be any layer, the scope of protection is shifted because, all of a sudden, different subject-matter is being protec­ted. Article 123(3) EPC expresses the principle that the public must be able to rely on the fact that the scope of protection cannot be extended.

Regarding Article 123(2) EPC, the decisive question is how paragraph [0008] of the patent is interpreted. Several aspects have to be taken into account:

- The notion of a "coating of a CSS" is not disclosed in the application as filed.

- Paragraph [0008] introduces a feature that was not disclosed in the application as filed and can be interpreted in several ways.

- It is not clear what the words "referred to as" in paragraph [0008] are actually referring to.

- If the appellant's interpretation is correct, a new definition has been introduced. It can be under­stood in such a way that the scope of protection is extended. If the respondent's interpretation is adopted, paragraph [0008] adds to the technical teaching of the patent.

- When conformity with Article 123(2) EPC is examined, the relevant criterion is "direct and unambiguous disclosure".

(ii) Appellant

The objections under Article 123(2) EPC are unfounded because claim 1 is identical to the original claim 36.

As far as Article 123(3) EPC is concerned, the skilled person would exclude one of the two allegedly possible interpretations, namely that the CSS itself is coated. Should the skilled person consider that several alter­natives are possible, the skilled person would have considered that all of them are encompassed in the scope of protection. The skilled person would have considered the description for defining the scope of protection and would have understood that paragraph [0008] explains that the patent as granted and auxiliary request 2 involve equivalent or synonymous elements. The interpretation of paragraph [0008] is not decisive. If the expressions "colour-shifting coating structures" and "coating of a CSS" designate the same thing, there is no problem under Article 123(2) EPC because it is made clear that the expression "colour-shifting coating structure" does not introduce anything new: no further meaning is added. There is just a new name for the colour-shifting coating structure. The technical content remains unchanged. The same holds true when the respondent's interpretation is adopted. Moreover, the way in which the reference in paragraph [0008] of the patent is interpreted is without consequence because both interpretations lead to the same result. The amendment was made to avert an objection of lack of clarity; it has no bearing on Article 123(2) EPC.