This opposition appeal considered the question whether an amendment extended the scope of protection. Claim 1 of the sole request contained the following features. The amendments are shown with respect to the claim as granted:
A glass
article with a metal member joined thereto,
(...)
(c) wherein
the two joining planes of the metal member are fixed (...) with a lead-free
solder alloy containing Sn as a main component, and
(...)
(e)
characterized in that the lead-free solder alloy is an Sn-Ag based alloy that
contains 2 to 4 mass% Ag, and a content of other minor components
except for Sn and Ag in the Sn-Ag based alloy is 0.5 mass% or lessin which the rest is Sn, and
The opponent objected (amongst other objections) that this amendment broadened the claim after grant. The board did not agree.
Summary of Facts and Submissions
(...)
The
patent had been amended in such a way as to extend the protection it
conferred (Article 123(3) EPC). Substituting in feature (e) the term "a
content of other minor components except for Sn and Ag in the Sn-Ag
based alloy is 0.5 mass% or less" from claim 1 as granted for "in which
the rest is Sn" extended the scope of the patent as granted.
The former
term limited the amount of other minor components, such as impurities,
in the alloy to up to 0.5 mass%, whereas according to the new wording
the amount of impurities could reach higher levels beyond 0.5 mass%.
Deletion of the former term therefore broadened claim 1. The patent as
granted did not specify what was to be understood by 'other minor
components'. These additional minor components had to be interpreted in
the patent as granted as any 'other element' within the alloy and
included also impurities. It was further common practice for the skilled
person that elements in the alloy composition which did not add up
together to 0.5 mass% of the alloy were not specified in the composition
but just generally referred to as other components. The skilled person
knew that impurities had a significant effect on the properties of a
metal alloy (see T 184/05), and their concentration level could not be
regarded in isolation from the specific examples.
(...)
Reasons for the Decision
2. Extension of scope of protection - Article 123(3) EPC
2.1
The amended European patent according to the sole request does not
extend the protection conferred within the meaning of Article 123(3)
EPC.
2.2 In its granted version, claim 1 determines the
composition of the lead-free solder alloy as including a content of
other minor components except for Sn and Ag of 0.5 mass% or less.
According to the documents of the present request, the above-mentioned
feature of granted claim 1 is replaced by "in which the rest is Sn", and
the last two sentences from paragraph [0020] of the description of the
granted patent have been deleted, namely: "The Sn-Ag alloy may contain
other minor components. In this case it is preferable that the content
of the minor components is 0.5 mass% or less".
2.3 Any reference
to other minor components has thus been deleted in the description. As
agreed by both parties, when explicitly claiming "other minor
components" the claimed solder alloy includes any kind of voluntarily
added elements as well as unavoidable ones such as impurities, in
particular because this term is not further specified in the patent as
granted (see paragraph [0020] of the description). Moreover, in the
Board's judgment, the sentence in paragraph [0020] that the "Sn-Ag alloy
may contain other minor components", i.e. that minor components can be
added on purpose or be excluded, would be contradictory if "other minor
components" were equated with "impurities", which by nature are
unavoidable.
By deleting the references to other minor components in
paragraph [0020] of the description, which clearly indicated that they
were optional components, and by the amendment to claim 1 as granted
according to the sole request, the composition of the claimed solder
alloy has been restricted to silver, tin and an unavoidable amount of
impurities, since it is well known to the skilled person that a solder
alloy will never be pure and thus contains unavoidable impurities.
Therefore,
with respect to the composition of the alloy solder as granted, the
scope of protection of the amended patent according to the sole request
has been limited to a lead-free Sn-Ag based solder alloy that contains 2
to 4 mass% of Ag, in which the rest is Sn, further, implicitly,
containing an unavoidable amount of impurities.
2.4 In accordance
with the respondent's opinion, the range of "0.5 mass% or less" claimed
in the granted version for the other minor components included as a
lower limit "0.0 mass%" of other minor components. The present request
is limited, due to the deletion of other minor components in claim 1 and
the definition that "the rest is Sn", to this lower limit, i.e. in this
respect the scope of protection has only been restricted compared to
the patent as granted.
2.5 It remains to be discussed whether,
based on claim 1 and the description of the sole request, the content of
unavoidable impurities might include an amount greater than 0.5 mass%
of the solder alloy, as alleged by the appellant. Starting from the
undisputed understanding of the term "other minor components" in granted
claim 1, comprising voluntarily added elements as well as unavoidable
impurities, their total content was explicitly restricted to "0.5 mass%
or less" in the granted version. In fact, this restriction was deleted
in claim 1 according to the sole request. However, as a further
limitation claim 1 according to the sole request now specifies a
composition "in which the rest is Sn".
In the absence of any evidence
that a content of impurities in the solder alloy could amount to more
than 0.5 mass% without being explicitly mentioned, the Board finds that,
on a reasonable interpretation of the subject-matter of claim 1
according to the present sole request, such content of unvoidable
impurities higher than 0.5 mass% must be ruled out. A person skilled in
the art describing the content of solder alloys would specify an element
of which the content is greater than 0.5 mass% of the alloy because it
will affect the properties of the alloy. In the Board's judgement, this
also applies to a group of elements in the alloy, such as impurities, if
their content exceeds 0.5 mass% because such impurity content would
have a considerable influence on the properties of a metal alloy, as
stated by the appellant himself.
In this context, the appellant
cites decision T 184/05, which again refers to decision T 201/83 (OJ EPO
1984, 481) stating (point 12 of the Reasons, last sentence) that "an
amendment of a concentration range in a claim for a mixture, such as an
alloy, is allowable on the basis of a particular value described in a
specific example, provided the skilled man could have readily recognised
this value as not so closely associated with the other features of the
example as to determine the effect of that embodiment of the invention
as a whole in a unique manner and to a significant degree". However, the
present application and the specific examples described therein are
totally silent with regard to impurities and their concentration range,
and only in the general part of the description, as originally filed, is
it mentioned that other minor components may - optionally - be included
up to a maximum content. Therefore, the the Board finds that the case
law referred to by the appellant - which relates to the extraction of a
particular value of a concentration range of an alloy from a given
example comprising further features - is considered not to be applicable
in the present case, which only excludes an optionally mentioned solder
alloy component. In particular, the Board finds that deletion of such
optional alloy composition with a limited content of other minor
components cannot open the door to an interpretation of the claimed
subject-matter which would include an unlimited or unreasonable amount
of impurities.
Moreover, as argued by the appellant, it was common
practice for the skilled person that elements in the alloy composition
which do not add up together to 0.5 mass% of the alloy were not
specified but just generally referred to as other components.
In the
absence of any citation of other minor components in claim 1, reading
claim 1 with a mind willing to understand (which comprises the term "in
which the rest is Sn"), the skilled reader would at the most assume an
insignificant amount - far below 0.5 mass% - of unavoidable components
such as unavoidable impurities.
2.6 The Board thus cannot see that the European patent has been amended in such a way as to extend the protection it conferred.
This decision has European Case Law Identifier: ECLI:EP:BA:2014:T182712.20140919. The whole decision can be found here. The file wrapper can be found here. Scan by Jamie obtained via Flickr; Original source The Toronto World, May 17, 1902.