T 0936/16 15-10-2019

Reasons for the Decision

1. Main request - amendments

1.1 In its communication dated 16 April 2015, which was re­ferred to in the contested decision being a formal decision according to the state of the file, the examining division held that fea­ture (ii) extended beyond the content of the appli­cation as filed contrary to the provisions of Article 123(2) EPC (see points 2 and 3 of the communica­tion).

1.2 The appellants argued that the specific phosphors for emitting red light cited in the description of the appli­cation (page 4, line 23 - page 5, line 2; page 8, lines 14-22) ­­were merely mentioned as examples of red light emitting phos­phors in general. It was evi­dent for the skilled person that it was the function of emit­ting red light which was important for achiev­ing the desired warm white colour tone (page 2, lines 24-27; page 6, lines 10-14). On the other hand, no importance had been at­tached to the fact that the phosphor was selected from the cited struc­tures. Also the fact that the expression "another phos­phor" was used (page 4, lines 23-24) im­plied that any red light emit­ting phosphor could be used for the stated pur­pose. Hence, feature (ii) did not extend beyond the content of the applica­tion as filed.

1.3 The board notes first that an amendment is only con­sid­ered to comply with the requirements of Article 123(2) EPC if it is directly and unambiguously deriv­able for the skilled person - using common general knowledge and seen objectively and relative to the date of filing - from the entire original disclosure (i. e. description, claims and drawings) (see Case Law of the Boards of Appeal of the EPO, 9th edition 2019, section II.E.1.3.1).

1.4 In the present case, there is no explicit disclosure of feature (ii) in the claims, description or drawings as filed. It remains to be examined whether the skilled person would derive this feature from the originally filed description, especially the passages in­di­cated by the appellants.

1.4.1 Generally, the light emitting device of the invention comprises a nitride semiconductor light emitting ele­ment for emitting blue light and a phosphor, which ab­sorbs part of the light emitted from the light emitting element and emits light of a different wavelength. In particu­lar, the phosphor is a europium-activated alka­line earth metal ortho­silicate emitting yellow light. Claim 1 of the main request relates to the first em­bod­i­ment of the invention ac­cord­ing to which the light emit­ting device comprises a second phosphor, namely a red phosphor as specified in feature (ii). The most relevant parts of the descrip­tion relating to this second phos­phor - contained in the section dis­clos­ing the inven­tion in general terms (see page 4, line 23 - page 5, line 2) and in the sec­tion disclos­ing the first embodi­ment in detail (see page 8, lines 14-22) -­­ read as follows:

"The light emitting device has, advantageously, an-other phosphor from the group of an alkaline earth metal alu­mi­nate activated by divalent europi­um and/or manganese, and/or Y (V, P, Si)O4: Eu or, a fur-ther different phos­phor for emitting a red light from the group of an al­ka­­line earth metal-magne-sium-disiliate [sic]: Eu**(2+), Mn**(2+) represented by the formula:

Me(3-x-y)MgSi2O3:xEu, yMn

(wherein 0.005 < x < 0.5, 0.005 < y < 0.5, and Me denotes Ba and/or Sr and/or Ca)."

"By using one selected from the above-mentioned group of the phosphors or a combination of phos-phors selected from the above-mentioned group, or a combination of a phosphor of alkaline earth metal aluminate activated by divalent europium and/or manganese, a further different phosphor to emit a red light selected from the group of Y(V, P, Si) O4:Eu**(2+), and a conventional phosphor selected from the group of Y2O2S:Eu**(3+), an emission light color with defined color temperature and a higher color reproducibility can be obtained."

In these passages it is explicitly disclosed that the red phosphor may be either a europium/manganese-acti­vated al­ka­­line earth metal-magnesium-disilicate or a europium-activated Y(V, P, Si)O4. However, they contain no indication that other red phosphors may be used in­stead of these disclosed ones. In particular, the ex­pressions "another phosphor" or "further phosphor" merely signify that a first phosphor is already present in the light emitting device and do not imply that any other phosphor may be used. Hence, the wording of these passages does not provide a basis for the gener­al­iza­tion from the concrete red phosphors disclosed in the above passages to the "phosphor for emitting a red light" as defined in feature (ii).

1.4.2 The effect of this generalization is that feature (ii) specifies not only the disclosed red phosphors men­tioned above, but also any other alternative phosphor for emitting red light. It remains to be considered whether the skilled person would find it evident in view of the disclosure of the appli­ca­tion that any one of these alternative phosphors could be used in the light emitting device instead of the disclosed phos­phors (cf. T 416/86, point 2.1.3 of the Reasons).

Concerning the purpose of the red phosphor the board has no reason to doubt the explanation given by the appellants that it allows the white tone to be adjusted accurately so ­that a warm white colour tone can be achieved. However, the skilled per­son would understand from the application that the red phosphor has the fur­ther function of improving the colour reproducibility, i. e. the ability of the light emitting device to re­veal the colours of various objects faithfully. This is also explici­tly mentioned in one of the passages cited above.

In order to be suitable for being used for the above pur­­poses in the light emit­­ting device of the invention, which comprises the blue light emitting ele­ment and the first yellow phos­phor, a red phosphor must fulfill cer­tain require­ments­. To begin with, the excitation wave­length must be adapted to the blue light emitting ele­ment so that the phosphor is able to absorb the blue light emitted from the light emitting element. Further­more, the red phos­phor also has to be adapted to the first yellow phos­phor in that as little light as possible emitted from the yellow phos­phor should be absorbed by the red phosphor in or­der not to spoil the contribution of the yellow phos­phor to the overall light output. Finally, in order to qualify as a phosphor to be used in a light emitting device the red phosphor must exhibit suffi­cient thermal stability, so that its light output does not decrease too much with increasing temperature.

In the opinion of the board the skilled person would not expect that all red phosphors fulfill these requirements. Hence, it cannot be considered evident that any one of the alternative red phosphors could be used in the light emitting device of the invention instead of the explicitly disclosed red phosphors.

1.5 In view of the above, feature (ii) is not directly and unambiguously derivable from the application as filed. Therefore, claim 1 of the main request contains sub­ject-matter extending beyond the content of the appli­cation as filed, contrary to the requirements of Arti­cle 123(2) EPC.

2. Auxiliary requests 1 and 2 - amendments

Claim 1 of the first and second auxiliary requests also contain feature (ii) and merely differ from claim 1 of the main request in comprising an amended definition of the first phosphor. Therefore - for the reasons stated under point 1. above - respective claim 1 of auxiliary requests 1 and 2 also contains subject-matter extending beyond the content of the application as filed, con­trary to the requirements of Article 123(2) EPC.

3. Conclusion

Since none of the requests fulfills the requirements of the EPC, the board confirms the examining division's decision refusing the application. Conse­quently the appeal has to be dismissed (Article 97(2) EPC and Article 111(1) EPC 1973).