T 1394/05 (Multilayered glass/PPG) 04-04-2008

Reasons for the Decision

1. Admissibility of patentee's appeal

1.1 According to Article 107, sentence 1 EPC, any party to proceedings adversely affected by a decision may appeal and, according to established case law, a party is adversely affected if the decision does not accede to its main request or to auxiliary requests preceding the allowed auxiliary request. In the present case, although the opposition division held in its interlocutory decision that the claims according to auxiliary request 2 met the requirements of the EPC, it did not accede to patentee's preceding broader claims. Therefore, the patentee/appellant II is adversely affected by the impugned decision according to Article 107, sentence 1 EPC.

1.2 The reason put forward for not admitting the patentee's appeal was based on the fact that the patentee never requested the maintenance of the patent as granted in the first instance. According to opponent I/appellant I, the patentee went beyond the scope of the appeal frame set by the opposition proceedings.

1.3 The board does not agree for the following reasons:

According to the established jurisprudence of the

Boards of Appeal (cf. T 934/02, reasons, point 3.2), "the EPC makes no provision for a patent proprietor to surrender his patent in opposition proceedings. This means that (even where there has been an express declaration of surrender, which is not the

case) he cannot surrender his patent either wholly or in part. The patent proprietor can only request that it be amended and, in principle, can withdraw or amend such a request at any time provided no abuse of procedural law is involved or unless in that particular case a prohibition on reformatio in peius applies. Accordingly a new version of the claim is to be regarded as a formulation attempt and not as a renunciation of more extensive protection (see i.a. T 123/85 OJ EPO 1989, 336, points 3.1.1 and 3.1.2 of the reasons and T 296/87 OJ EPO 1990, 196, point 2 of the reasons). In other words, even the patent proprietor which has defended his patent only to a limited extent in opposition proceedings is not a priori prohibited from returning during the appeal proceedings to a broader version, including the granted version, of its patent, since intervening limitations of the patent do not imply any renunciation of parts of the patent but are rather to be regarded merely as attempts to word the patent so as to delimit it against objections."

The same reasoning applies to the present case. The patentee/appellant II is not bound to its restricted requests before the first instance and is allowed to resume its former request for maintenance of the patent as granted. The legal question of whether this request could be refused by the Board as belated does not concern the admissibility of the appeal according to Article 107, sentence 1 EPC. Accordingly, the board concludes that the patentee's appeal is admissible.

2. Admissibility of oral submissions by one of the inventors

The board rejected at the oral proceedings the request of the patentee/appellant II to allow Dr. Mehran Arbab to make an oral presentation because the request as submitted in written form did not specify the subject-matter of the proposed oral submissions, so that at least criteria i) set out in item 3(b) of the Order of Enlarged Board of Appeal decision G 4/95 was not met. As opponent I/appellant I furthermore objected to such a presentation being made, and as the board did not see any exceptional circumstances (according to 3(b) (iii) of the said order) to allow such a presentation, the request was rejected.

3. Interpretation of claim 1 - all requests

3.1 As claim 1 of all the requests on file recites the feature "a metallic film being silver and having a preferentially oriented growth of grains" and as the parties had divergent opinions as to its meaning, this feature has to be interpreted in the light of the description of the contested patent.

3.2 Patentee/appellant II argued at the oral proceedings - by referring in particular to the paragraphs [0108] to [0110], [0118] and [0120] - that in the contested patent, the orientation of the silver film was corroborated by various diffraction spectra wherein the {220} peak rose above the {111} peak. It admitted that this definition corresponded substantially to the subject-matter of a dependent claim in all the requests (e.g. dependent claim 7 of the main request), but it was not inclined to restrict the subject-matter claimed with such features because in its opinion the "preferentially oriented growth of silver" could also be interpreted in other ways, for instance by the size of the silver grains, which grains were viz. "larger" in the case of a "preferentially oriented growth" as compared to a non-oriented growth.

In its letter of 22 August 2006, patentee/appellant II further stated inter alia that "a diffraction pattern different from that of a powder, with some peaks rising, others diminishing" (page 4, lines 19 to 24), was an indication for a preferential crystallographic orientation of the respective layer. The board observes that this statement substantially reflects the content of paragraphs [0106] to [0111] and [0148] of the contested patent, wherein the allegedly inventive silver film with a preferentially oriented growth of grains is defined in contrast to a randomly oriented growth of crystal grains within the silver film or by opposition to a multigrained, or polycrystalline, film with a random orientation having a diffraction pattern or spectrum similar to that of a silver powder sample.

3.3 In view of these findings that the content of the contested patent allows for a very broad interpretation of the feature "a metallic film being silver and having a preferentially oriented growth of grains", it is the board's view that this feature is equivalent to a crystallized metallic silver film which is not polycrystalline, i.e. made up of grains of crystalline material where the grains are randomly oriented relative to each other.

4. 9th auxiliary request - Inventive step

For reasons of procedural economy, the board decided at the oral proceedings to first analyse the issue of inventive step with respect to the subject-matter of claim 1 of the 9th auxiliary request, which corresponds in its essence to that of claim 1 maintained in the contested patent.

4.1 As indicated in paragraph [0007] of the contested patent, the alleged invention relates to a high transmittance, low emissivity coated article comprising a) a transparent nonmetallic substrate,

b) a metallic film having a preferentially oriented growth of grains and

a dielectric antireflective base film comprising

c) a crystalline metal-contact film situated between the substrate and the metallic film [of a first material] (sic) and in contact with the metallic film, the crystalline film being coordinated with the metallic film.

In claim 1 of the present request, the metallic film b) is silver, the crystalline-metal contact film c) is of zinc oxide or zinc aluminum oxide and the antireflective base film consists of two film-parts, namely c) and d), the second film-part d) being an amorphous oxide of zinc and tin and being in contact with the substrate and supporting the crystalline-metal contact film c).

4.2 In accordance with the "problem-solution approach" applied by the boards of appeal to assess inventive step on an objective basis, it is in particular necessary to establish the closest state of the art, to determine in the light thereof the technical problem which the invention addresses and successfully solves and to examine the obviousness of the claimed solution to this problem in view of the state of the art.

4.3 The board considers, in agreement with the parties, that document E11 represents the closest state of the art, and hence, the starting point in the assessment of inventive step.

Document E11 relates to a low emissivity film excellent in durability, especially in moisture resistance or in acid resistance (page 2, lines 1 and 2).

According to claims 1 to 5 of E11, the low emissivity film comprises:

a substrate; and

a coating of oxide and metallic films alternately formed on the substrate in a total of (2n+1) layers, where n is an integer equal to or more than 1, with the innermost layer being an oxide film,

wherein:

- the major component of the metallic film (a) is Ag,

- the oxide film (b) formed on the outer side of the metallic film (a) most apart from the substrate is composed of a single layer or a multi-layer having at least a layer of which major component is zinc oxide the crystal structure of which is hexagonal, and a value of a diffraction angle 2theta (center of gravity position) of (002) diffraction line of the hexagonal zinc oxide in X-ray diffraction method using CuKalpha radiation, is preferably not smaller than 34.00º and not larger than 34.88º and wherein the oxide film (b) has an internal stress which is equal to, or less than 1.1 x 10**(10) dyne/cm**(2).

Such a low emissivity (Low-E) film is electrically conductive (E11, page 9, line 26) and a glass, in which such a low emissivity film is formed (also called low-E glass) is transparent and electrically conductive (E11, page 2, lines 2 to 11).

4.4 In the light of document E11, the patentee/appellant II was of the opinion that the problem to be solved was to provide a high transmittance, low emissivity coated article having low electrical resistivity and high durability.

4.4.1 The board does not agree for the following reasons:

E11 also relates to a low emissivity film excellent in durability (page 2, first two lines), further described as being electrically conductive (page 9, lines 36 and 27), i.e. as having a low resistivity. Glass articles coated with such a low emissivity film are furthermore described as having visible light transmittance (page 6, line 49 to page 7, line 1).

In this context and in the absence of comparative data between the claimed coated article and those of E11, it must be concluded that the latter exhibit - at least qualitatively - the same properties as the coated article presently claimed.

4.4.2 Accordingly, as no improvement over E11 can be acknowledged to the coated article defined in claim 1 of the 9th auxiliary request, the problem to be solved has to be reformulated into a less ambiguous one, namely in the provision of an alternative coated article having the above properties.

4.4.3 As a solution to this problem, the patent in suit proposes an article as defined in claim 1 comprising in particular a second film-part d).

4.4.4 Although the parties unanimously conceded that E11 did not disclose a second film-part d) as defined in present claim 1, appellant II/patentee argued that in addition to this distinguishing feature, E11 did also not disclose the combination of a crystalline film of zinc oxide in contact with a metallic silver film having a preferentially oriented growth of grains.

This argument however fails for the following reasons:

(a) In Example 5 of E11, a glass/ZnO/Ag/ZnO multilayered coated article is prepared by successive deposition on a glass substrate of films with thicknesses of 450 A, 100 A and 450 A, respectively, using an RF sputtering method. The materials of the targets used are ZnO and Ag, and the sputterings are performed in an argon gas atmosphere. The sputtering pressure is 1.8 x 10-3Torr, the substrate temperature is room temperature and the power density is 3 W/cm**(2). After deposition, the film is heat treated at 400ºC in an N2 atmosphere for 1 hour. After heat-treatment, the Low-E film is analyzed by an X-ray diffraction method and the diffraction angle 2theta (center of gravity position) of (002) diffraction line of ZnO is found to be 34.42º. As indicated in the passage at page 4, lines 28 to 30 of E11, the crystal structure of such an oxide film - whose major component is zinc oxide - is hexagonal.

(b) E11 does not explicitly disclose the crystalline structure of the zinc oxide film below the silver layer. However, in the coated article prepared in Example 5, the zinc oxide film below the silver layer exhibits the same thickness and composition, and has been prepared under the same conditions, as the upper ZnO film. In this context, as same process conditions lead to the same product, the crystal structure of the lower zinc oxide film should thus be substantially identical with that of the upper ZnO film and exhibit as well the (002) diffraction line of crystalline hexagonal zinc oxide.

(c) In view of these findings and since it has furthermore been unanimously agreed by the parties that silver grows epitaxially on crystalline zinc oxide (i.e. with the same crystalline orientation as the substrate on which it is grown), such a growth also inevitably occurs in the coated glass of Example 5 at the interface with the lower crystalline zinc oxide film, and therefore the silver film in this Example cannot be polycrystalline, but necessarily has a "preferentially oriented growth of grains" in the sense of claim 1 of the present request.

(d) For these reasons, it is concluded that the subject-matter of claim 1 of the 9th auxiliary request can be distinguished from the disclosure of document E11, in particular from the coated glass of Example 5, in that the antireflective base film consists of a metal-contact film-part and a support film-part, whereby the support film-part is an amorphous oxide of zinc and tin and in contact with the substrate.

4.4.5 Thus, the solution as proposed in claim 1 of the 9th auxiliary request to the problem defined under point 4.4.2 differs from the coated articles of E11, in particular those of Example 5, in that a dielectric, antireflective support film-part being an amorphous oxide of zinc and tin and in contact with the substrate is located below the lower crystalline zinc oxide film.

4.5 Although the board is satisfied that this solution successfully solves the problem defined above, the question arises whether or not the proposed solution is obvious in view of the cited state of the art.

4.5.1 In this respect, E3 discloses (column 3, lines 21 to 23) that ZnO films are insufficiently durable and that an improvement as regards this property can be observed with films of an oxide of zinc and tin (E3, column 4, lines 15 to 24).

E3 furthermore concerns high transmittance, low emissivity coated articles comprising a transparent nonmetallic substrate and a transparent infrared reflective metallic film sandwiched between two transparent antireflective metal oxide films (claim 1). In the paragraph headed "summary of the invention" (column 4, lines 15 to 27), E3 discloses such a coated article in which the substrate, the first antireflective metal oxide film and the infrared reflective metallic film are respectively glass, silver and an oxide of zinc and tin.

Accordingly, E3 concerns coated glasses similar to those of the contested patent and in this context, the skilled person faced with the problem of providing an alternative to the coated article of Example 5 of E11 would consider the inclusion of the first transparent antireflective oxide film of an oxide of zinc and tin of E3 as a normal design option, insofar as the latter material was suggested in E3 as a substitute with higher durability for zinc oxide dielectric antireflective layers.

4.5.2 As E11 (page 6, lines 43 to 46) furthermore suggests that the material of the oxide film below silver may be composed of "a film in which at least two layers of ZnO, SnO2, and ZnO-SnO2 are alternatively laminated", the skilled person is not deterred from adding a further base film to the coated glasses known from E11.

The fact that claim 1 of E3 requires the presence of the layers c) and e), i.e. a transparent metal oxide/metal primer layer deposited on the first antireflective metal oxide film and a metal-containing primer layer be deposited on the infrared reflective metallic film, respectively, does also not deter the skilled person from combining the teaching of E3 with that of E11 because the "metal oxide/metal primer" of said transparent layer c) is not specified in claim 1 of E3, so that the lower zinc oxide layer of E11 can be such a "transparent metal oxide/metal primer layer". Furthermore, owing to the presence of the word "comprising" in claim 1 of E11, further upper additional layers - such as the layer e) of E3 - are not excluded from E11. The teachings of E3 and E11 are therefore not incompatible and they can thus be combined.

4.5.3 After combination of the teachings of documents E11 and E3, one difference with respect to the subject-matter of claim 1 of the present request remains: the oxide of zinc and tin of the support film-part in contact with the substrate is amorphous.

As regards this specific feature, the board observes that there is no evidence neither in the contested patent nor in the file that the use of an amorphous oxide of zinc and tin would provide a particular effect over other types of an oxide of zinc and tin. On this basis, the choice by the skilled person of the specific "amorphous" oxide of zinc and tin among a limited number of possibilities of oxides of zinc and tin (amorphous, crystalline or semi-amorphous) lies within the routine activity of the skilled person faced with the problem of finding an alternative coated article. Such a choice can however not confer any inventive merit to the claimed coated article.

4.6 In view of the above findings, the board concludes that the subject-matter of claim 1 of the 9th auxiliary request is obvious to a person skilled in the art and therefore does not fulfil the requirements of Article 56 EPC.

5. Higher ranking requests - Inventive step

5.1 The subject-matter of claim 1 of the 3rd and 7th auxiliary requests being identical to that of the 9th auxiliary request, these requests are not allowed for the same reasons as the 9th auxiliary request.

5.2 The subject-matter of each claim 1 of the other higher ranking requests up to the 8th auxiliary request includes the same combination of features as claim 1 of the 9th auxiliary request, namely:

- "a metallic film being silver and having a preferentially oriented growth of grains",

- "a crystalline metal-contact film of zinc oxide in contact with the metallic film, the crystalline film being coordinated with the metallic film", and

- "a support film-part being an amorphous oxide of zinc and tin and in contact with the substrate"

The reasoning set out under points 3. and 4. supra applies thus mutatis mutandis to the subject-matter of the claims cited hereinabove, which therefore do also not meet the requirements of Article 56 EPC.

Consequently, the main request as well as the 1st, 2nd, 4th to 6th and 8th auxiliary requests cannot be allowed.

6. 10th auxiliary request - Clarity

6.1 The subject-matter of claim 1 of this request contains the amendment that the zinc oxide is "sputtered from a cast zinc metal target in a preponderance of oxygen over argon".

6.2 This amendment being solely based on the description of the granted patent (page 5, lines 4 to 7), the subject-matter of claim 1 of the present request does not result from the combination of claims of the patent as granted and thus does not concern a specific object which as such was already claimed in the patent as granted.

Accordingly, the amended claim 1 must be examined for compliance with all requirements of the EPC, including clarity. In this respect, the question arose at the oral proceedings as to the meaning of the feature "in a preponderance of oxygen over argon".

6.3 The patentee/appellant II argued that the amendment at stake meant "in the presence of more oxygen than argon". In this respect, it referred to Figure 9 of the contested patent and indicated that by comparing the data of the samples G, H and J, it was clear for the skilled person reading the contested patent that said feature had the above meaning.

6.4 The board cannot accept these arguments for the following reasons.

6.4.1 The patent is totally silent as to the meaning of the feature "in a preponderance of oxygen over argon" and although Figure 9 describes that a zinc oxide sputtered in an atmosphere having an oxygen concentration of 80% generates a silver film having a lower resistance (samples H and J) than a silver film coated on a zinc oxide film similarly sputtered in an atmosphere containing 50% oxygen (sample G), the board does not accept that the teaching of these three specific samples can be generalized so that the feature "in a preponderance of oxygen over argon" is to be considered as meaning "in the presence of more oxygen than argon", as argued by Appellant II.

6.4.2 The board is much more of the opinion that the expression "in a preponderance of" can be interpreted differently and for instance, as argued by the opposing parties, it can as well mean "with a superiority in power" or "with a superiority in reaction intensity".

6.4.3 In this context, as different interpretations are possible for the above feature, the board concludes that the subject-matter of claim 1 of the 10th auxiliary request is ambiguous and therefore not clear, contrary to the requirements of Article 84 EPC.

6.5 In view of the above findings, the 10th auxiliary request cannot be allowed.

7. 11th to 16th Auxiliary request - Clarity

As at least one claim in each of the remaining requests contains the feature "in a preponderance of oxygen over argon" in the following respects:

- 11th auxiliary request: claim 13;

- 12th auxiliary request: claim 1;

- 13th auxiliary request: claim 13;

- 14th auxiliary request: claim 1;

- 15th auxiliary request: claim 12;

- 16th auxiliary request: claim 1,

the above reasons apply mutatis mutandis to the subject-matter of these claims, which therefore also do not meet the requirements of Article 84 EPC.

Consequently, the 11th to 16th auxiliary requests are also not allowed.