T 0058/94 21-11-1996

1. The appeal is admissible.

2. Main request

2.1. Allowability of the amendments

2.1.1. The slide according to claim 1 of the main request is for use in the examination of a liquid specimen; said slide (10) comprises:

a base plate (14) having at least one flat examination chamber floor surface (16), said examination chamber floor surface being raised above an upper deck surface (20) of said base plate;

said slide (10) also comprises:

a cover plate (12) having at least one flat examination chamber roof surface (24), said examination chamber roof surface being recessed from a lower surface (22) of said cover plate, the said examination chamber roof surface being positioned over the said examination chamber floor surface and being spaced therefrom;

said slide (10) further comprises:

depth-control means (26) for determining the distance by which the said roof surface is spaced from the said floor surface so as to provide an examination chamber (28) having a substantially constant depth, and bonding means (30) whereby the base plate and the cover plate are bonded together;

in said slide (10), the depth control means is situated adjacent a portion of the perimeter of the examination chamber and the bonds between the base plate and the cover plate are at locations spaced from the perimeter of the examination chamber.

2.1.2. It has not been contested that the two following features, which read in substance as follows and which were disclosed in the original application (see in particular independent claims 1 and 2), are not comprised in present claim 1:

"(a)": the examination chamber roof surface has a smaller surface area than the examination chamber floor surface, and there is a depth control ridge extending away from the examination chamber roof surface on all sides, but one, a sufficient distance to provide the combination of the examination chamber roof surface and depth control ridge with a surface area larger than that of the examination chamber floor surface so that when the examination chamber roof is positioned over said examination chamber floor surface a fixed distance determined by said depth control ridge is maintained between said examination chamber roof and floor surfaces;

"(b)": the depth control ridge has at least one notch extending between the examination chamber roof and the edge of said control ridge furthest from said examination chamber roof.

2.1.3. The appellant has submitted that the fact that features (a) and (b) were present in the original independent claims does not determine (i.e. affect) the issue, for, as stated in the headnote of the above-mentioned decision T 0066/85, if "a technical feature is deleted from a claim ... in order not to exclude from protection certain embodiments of the invention, the broadening of the claim does not contravene Art. 123(2) EPC as long as there is some basis for a claim lacking that feature in the application as originally filed. It is immaterial whether or not the feature in question is relevant to the inventive concept of the claimed subject-matter".

Having especially regard to feature (b), the appellant has argued that this feature should be considered as solving some ancillary problem of the prior art, as compared to other features of the invention which are derivable as constituting a "critical requirement" of the invention; thus, it should be readily apparent from the original application that the venting of gases from the examination chamber is not relevant to that critical requirement, which in accordance with the original description (see page 3, line 22 to page 4, line 24) is the obtaining and maintaining of accurate spacing between the floor and roof surfaces of the examination chamber, and any means for venting entrapped gases is clearly not essential to the solution of the primary problem and hence must be considered as optional (notwithstanding that it might well be preferable).

2.1.4. However, the appellant's argument with respect to feature (b) is not convincing for the following reasons:

According to the original application (see in particular page 6, lines 10 to 17), the notches in the depth control ridges provide channels for bleeding entrapped gases from the examination chambers and for draining excess specimen fluids from the examination chambers. Thus, a definite function is indicated originally in relation to feature (b).

According to the above-mentioned headnote of Decision T 0066/85, it may be possible, under certain conditions, to delete a technical feature from a claim in order not to exclude from protection certain embodiments of the invention; indeed, in said decision T 0066/85 (see points 7 and 8 of the reasons), for allowing an amendment, reference is made to an originally illustrated embodiment which could be excluded from protection by the original claims. However, in the present case, the appellant has not specified which embodiments in the original description could be considered as being excluded from protection by the original claims 1 and 2, and none could be detected by the Board.

Moreover, according to said same above-mentioned headnote of Decision T 0066/85, there must be some basis for a claim lacking that feature in the application as originally filed, and such basis has neither been indicated by the appellant nor could it be detected by the Board.

Since as also mentioned in the cited headnote of Decision T 0066/85 it is immaterial whether or not the feature in question is relevant to the inventive concept of the claimed subject-matter, the appellant's considerations about the optional significance of the feature do not concern directly the objection about the deletion of corresponding features from original claims. In any case, it is to be noted that, as indicated here above, the invention is disclosed originally (see page 4, lines 25 to 31) as having examination chambers from which entrapped gases can be readily bled, and from which excess specimen fluids can be readily drained, and that, contrary to the slide with notches in the depth control ridges of feature (b) in original claims 1 and 2, the slide of present claim 1 does not comprise any feature which can be related to this function.

2.1.5. The appellant has submitted the additional argument, by reference to the statement in item 6 of the decision T 0331/87, that a feature "may be inessential even if it was incidentally, but consistently, presented in combination with other features of the invention". However, this argument is not convincing for the following reasons:

As indicated here above, the invention is disclosed originally (see page 4, lines 25 to 31) as having examination chambers from which entrapped gases can be readily bled, and from which excess specimen fluids can be readily drained, without any derivable indication that this function is inessential. Yet, contrary to the slide with notches in the depth control ridges of feature (b) in the original application (see in particular claims 1 and 2), the slide of present claim 1 does not comprise any feature which can be related to this function.

2.1.6. Therefore, since present claim 1 in particular does not comprise the originally disclosed capability related to the feature with notches in a depth control ridge, it corresponds to slides which were not disclosed originally and, thus, the main request does not satisfy the requirement of Article 123(2) EPC) that a European patent application may not be amended in such a way that it contains subject-matter which extends beyond the content of the application as filed.

3. First auxiliary request

3.1. Claim 1 contains as compared to the main request the additional feature that

the slide comprises means (44) whereby entrapped gases can be bled from the examination chamber (28) and excess specimen fluid can be drained from the examination chamber.

3.2. It is to be noted that, in particular, the above-mentioned original feature (a) is not comprised in claim 1 of the first auxiliary request. Said feature (a) consists of two partial features, i.e.

(a'), that the examination chamber roof surface has a smaller surface area than the examination chamber floor surface, and

(a''), that there is a depth control ridge extending away from the examination chamber roof surface on all sides, but one, a sufficient distance to provide the combination of the examination chamber roof surface and depth control ridge with a surface area larger than that of the examination chamber floor surface so that when the examination chamber roof is positioned over said examination chamber floor surface a fixed distance determined by said depth control ridge is maintained between said examination chamber roof and floor surfaces.

Moreover, the above-mentioned further original feature (b) is not comprised either in claim 1 of the first auxiliary request, i.e., it is not specified that the depth control ridge has at least one notch extending between the examination chamber roof and the edge of said control ridge furthest from said examination chamber roof.

3.3. The appellant has submitted that it is readily apparent for the skilled reader that various alternatives are possible to the notch disclosed in the illustrated embodiments. However, this argument is not convincing because no such alternative is clear to the Board and because, in any case, no basis could be detected in the original application for such alternative.

With respect to the same feature of the notch in the depth control means, the appellant has also submitted arguments that said feature is not an essential feature of the invention as originally disclosed and that, taking into account the conclusions of the Decision T 0331/87, said feature can thus be removed. However, since Decision T 0331/87 (see point 7.5 of the reasons) requires that the removal of a specific embodiment which is not indispensable to the function of the invention should not require any modification of the other features of the invention, and since as mentioned here above there is no clear alternative to said feature and thus a modification of the other features of the invention, i.e. of features which are not related to the depth control ridges or to the notches, cannot be excluded, the conclusions of Decision T 0331/87 cannot be directly transposed to the present case.

3.4. Therefore, since claim 1 of the first auxiliary request in particular does not comprise the originally disclosed feature concerning notches in a depth control ridge, it corresponds to slides which were not disclosed originally and, thus, the first auxiliary request does not satisfy the requirement of Article 123(2) EPC.

4. Second auxiliary request

Claim 1 contains as compared to the first auxiliary request the additional feature that

the depth control means is in the form of a ridge (26) extending away from a first of said flat examination chamber surfaces (16, 24) on all sides but one, said first flat surface having a smaller area than the other of said flat surfaces (24, 16), such that the ridge abuts the said other surface and defines a portion of the perimeter of the examination chamber.

However, contrary to the slide of the original application (see in particular page 4, lines 25 to 31 and page 6, lines 10 to 17) wherein there is at least one notch cut into each depth control ridge which provide channels for bleeding entrapped gases from examination chambers and for draining excess fluids from the examination chambers, the slide according to present claim 1 comprises means for the same function, but which can be different from the depth control ridges and the at least one notch therein. Therefore, since present claim 1 concerns slides which were not disclosed originally, it is not allowable for the same reasons as those mentioned here above in relation to the first auxiliary request.

5. Third auxiliary request

5.1. Since as in claim 1 of the second auxiliary request the slide of the third auxiliary request comprises means for the function of bleeding entrapped gases from examination chambers and of draining excess fluids from the examination chambers which can be different from the depth control ridges and the at least one notch therein derivable from the original application, it is not allowable for the same reason as those mentioned here above in relation to the second auxiliary request.

6. Fourth auxiliary request

It is to be noted that, contrary to claims 1 and 2 of the application as originally filed, claim 1 of the fourth auxiliary request indeed comprises the features (a'') and (b) mentioned here above in paragraphs 2.1.2 and 3.2, respectively, but does not include the feature (a') mentioned in said same last paragraph,

that the examination chamber roof surface has a smaller surface area than the examination chamber floor surface area.

As convincingly argued by the appellant, there are parts of the application as originally filed (see page 11, line 31 to page 12, line 7; Fig.4 and 5) which clearly teach that the examination chamber roof may be extended beyond the limit of the examination chamber floor and, thus, clearly contemplate embodiments having an increased surface area of the examination chamber roof. Therefore, there is a basis, in the application as filed, for a slide wherein the examination chamber roof surface has not a smaller surface area than the examination chamber floor surface area. Thus, claim 1 of the present fourth auxiliary request satisfies the requirement of Article 123(2) EPC that a European patent application may not be amended in such a way that it contains subject-matter which extends beyond the content of the application as filed, so that consideration of the further request is not necessary and the patent application may be remitted to the Examining Division for further prosecution.