T 0737/13 27-05-2014

1. The appeal is admissible.

2. Main request - Novelty and inventive step

2.1 The second auxiliary request underlying the interlocutory decision under appeal constitutes the present main request. Claim 1 of this request is directed to a method of assessment of a quantity and/or quality parameter of biological particles in blood or in a blood product. The claimed method requires, among other features, applying a volume of a liquid sample to a sample compartment having an exposing area, exposing a spatial image of electromagnetic signals from the sample compartment onto a two-dimensional array of detection elements under a linear enlargement smaller than 10:1, and processing the intensities detected by the detection elements so that signals from the biological particles are identified as distinct from background signals.

Document D1 discloses a process for counting particles, in particular blood particles, in a fluid sample passing through an optical cell comprising the steps mentioned in the former paragraph (abstract and Figure 1, together with the corresponding description, and page 6, lines 3 to 5). In its decision the opposition division found that document D1 required a sample flow and held that the claimed method was novel and involved an inventive step over the disclosure of document D1 by virtue of the claimed feature "the volume of liquid sample is at stand still during the exposure". During the appeal proceedings the appellant has contested the opposition division's view in this respect and the respondent has not disputed that, apart from this feature, the remaining features of the method of claim 1 are anticipated by document D1.

The issue of novelty and inventive step of the claimed method therefore boils down to the question of whether the claimed feature "the volume of liquid sample is at stand still during the exposure" is anticipated or at least rendered obvious by the disclosure of document D1.

2.2 In the method of document D1 the step of exposing the two-dimensional array of detection elements to an image of the fluid sample is carried out as the fluid sample flows through the optical cell so that detection takes place as the exposure image is moving across the detector array (abstract together with the paragraph bridging pages 2 and 3). The further reference in the document to the information from the detector array being "sampled as 10 «frame freeze pictures»" and being "real time information from a moving fluid" (page 8, lines 15 to 21) further corroborates this finding. The Board therefore concurs with the respondent that the measurement method of document D1 relies on movement of the fluid sample during exposure, and that consequently the document excludes carrying out measurements on a fluid sample that is held stationary or at rest with respect to the detector array.

However, this finding does not necessarily imply that document D1 excludes that the volume of fluid sample is at "stand still during the exposure", at least not within the meaning of the patent in suit. Indeed, the technical concept of "stand still during the exposure" is not synonymous with stationary or at rest in absolute terms, but it rather describes a physical condition with reference to the exposure time and therefore constitutes a relative term. This view is in addition confirmed by the patent specification which, as agreed by both parties, provides a definition of what is to be understood by "stand still during the exposure" in the context of the claimed invention. Indeed, according to paragraph [0050] of the description of the patent specification (corresponding to the last paragraph on page 15 of the application as originally filed) the liquid in which the particles to be measured are suspended "is at stand-still, where stand-still is defined as the situation where at least apart [sic] of the image of a particle does not move any more than it is contained substantially within the boundary of the same detection elements during one measurement period." The same paragraph further reads: "The stand-still situation is preferably such that at least a part of the image of a particle does not move any more than it is contained substantially within the boundary of the same detection element during at least two measurement periods".

Thus, the stand-still condition of the volume of liquid sample is defined in claim 1 with reference to the exposure and according to the patent specification this condition is determined with reference to the boundary of the detection elements "during one measurement period", and preferably "during at least two measurement periods"; consequently, the mentioned condition depends not only on the state of movement of the sample, but also on the actual value of the exposure time or the measurement period. It follows that, contrary to the respondent's submissions, the claimed method does not actually exclude movement of the volume of the liquid sample, it rather allows movement of the volume but only to the extent implied by the above definition. In addition, the claim is silent as to the value of the exposure time and the value of the measurement period, and consequently the claimed stand-still condition can even be satisfied for volumes of the liquid sample flowing at a significant speed when the exposure time or the measurement period is sufficiently small.

This conclusion is, as noted by the appellant, also in conformity with the disclosure of the application as originally filed which contemplated the possibility that the sample "is moved through the domain or sample compartment during the exposure, and the exposure is performed over a sufficiently short period of time so [sic] substantially obtain stand still condition during the exposure" (page 20 of the application as originally filed, lines 28 to 31). This statement confirms that the "stand still condition during the exposure" can be achieved with a moving sample by selecting a sufficiently short exposure time or a sufficiently short measurement period and that, contrary to the respondent's submissions, the claim condition does not require stopping the sample.

As already mentioned above, in document D1 the exposure image, during exposure, moves across the detector array, and according to the disclosure of the document as the images of the particles traverse the detector array "the information concerning each particle can be checked several times. Sampling will generally be of the order of 50 times per second." (page 3, lines 22 to 28). In addition, the document proposes in this context that "If the particle stream is found to be moving too fast for accurate counting, the speed may be controlled, for example by feedback of information from the CCDs" (page 3, lines 28 to 31). In the Board's opinion the skilled person would see in this proposal a clear teaching that the accuracy in the counting of particles can be improved by reducing the value of the flow speed of the fluid volume relative to the exposure time or the measurement period of the detector array. The skilled person seeking to implement this teaching in order to improve the accuracy of the particle counting process would therefore slow down the fluid flow with respect to the exposure time or the measurement period, depending on the circumstances to an extent such that at least a part of the image of a particle imaged on the detector array would not move beyond the boundary of the same detector elements to the degree referred to in the patent specification during one or, if appropriate, during two consecutive measurement periods.

Thus, a straightforward application of the technical teaching of document D1 would lead to a method in which the volume of the liquid sample would be "at stand still during exposure" within the meaning of this expression given in the patent specification.

The respondent has submitted that the skilled person would not consider slowing down the flow in document D1 to such an extent, let alone to stop the flow, because this would undermine the characteristics of the flow required in the document, such as the movement of a thin stream of sample liquid past the detector and the imaging of a thin slice of the fluid sample (page 5, lines 1 to 4 and 16 to 19), and would also go against the teaching of the document which requires taking several pictures of each particle as it moves (page 8, lines 15 to 18). However, none of the features of claim 1, and in particular the stand-still condition of the volume of liquid sample relative to the exposure and the use of a sample compartment, excludes a sample flow, and document D1 teaches to slow down the flow relative to the exposure time or the measurement period of the detectors, without however stopping the flow. In addition, the characteristics of the flow mentioned above depend on the absolute value of the speed of the flow, and what document D1 teaches is reducing the relative value of the speed of the flow with respect to the exposure time or the measurement period; the skilled person following this teaching would therefore select a sufficiently low flow speed relative to the exposure time or the measurement period in such a way that the characteristics of the flow required in document D1 are still preserved.

The respondent has also submitted arguments concerning the technical improvements achieved over the disclosure of document D1 when the flow is stopped. However, as already concluded above, the claimed subject-matter does not require carrying out the measurements on a stationary sample, and consequently the claimed method includes embodiments in which a certain degree of flow or movement of the sample in relation to the exposure time or the measurement period is allowed; the technical improvements submitted by the appellant are therefore not supported by the subject-matter actually claimed.

Having regard to the above, the Board concludes that the method defined in claim 1 results in an obvious way from the disclosure of document D1 (Article 56 EPC).

3. First and second auxiliary requests - Inventive step

Claim 1 of the first auxiliary request differs from claim 1 of the main request in that the expressions "processing [of] the intensities" now read "processing [of] the image", and claim 1 of the second auxiliary request differs from claim 1 of the first auxiliary request in that the claim further specifies that the image processing involves "using image processing means and methods" (cf. point IV above). As noted by the respondent during the proceedings, these amendments emphasize that what is processed in the claimed method are images, and not just intensity signals, i.e. that the image is detected and processed as an image.

These amendments were made by the respondent in order to emphasize the differences between the method of the invention and prior art disclosures considered during the proceedings other than document D1, and there was no submission that these amendments would imply additional distinguishing features over the disclosure of document D1 beyond those considered in point 2 above, or that they would influence the assessment of inventive step over document D1.

If follows that the amendments to claim 1 according to the first and the second auxiliary requests have no impact on the assessment of inventive step made in point 2 above with regard to claim 1 of the main request. For this reason the method defined in claim 1 of these two auxiliary requests does not involve an inventive step for the same reasons as those given above with respect to claim 1 of the main request (Article 56 EPC).

4. Third auxiliary request - Inventive step

Claim 1 of the third auxiliary request differs from claim 1 of the main request in that the claim specifies explicitly what is meant by "stand still during exposure", i.e. "as the situation where at least a part of the image of a particle does not move any more than it is contained substantially within the boundary of the same detection elements during one measurement period" (cf. point IV above).

This definition of the claimed stand-still condition corresponds to the definition given in the description of the patent specification, and the assessment of inventive step of claim 1 of the main request in point 2 above was made on the basis of this definition. Accordingly, the incorporation of the definition in the formulation of the claim has no impact on the assessment of inventive step in point 2 above, and therefore the method of claim 1 of the third auxiliary request does not involve an inventive step for the same reasons as those given above with respect to claim 1 of the main request.

5. Fourth auxiliary request - Inventive step

Claim 1 of the fourth auxiliary request differs from claim 1 of the third auxiliary request in that the stand-still condition is not defined with reference to "one measurement period", but with reference to "two measurement periods" (cf. point IV above).

This definition of the claimed stand-still condition corresponds to the preferred embodiment given in the description of the patent specification and already considered in point 2 above. The amended definition, however, does not change the assessment of inventive step in point 4 above because in document D1 the area of the image of each particle on the detector array is of the order of the area of the detector elements (page 3, lines 12 to 18 together with page 2, lines 14 to 22 and claim 1) and the amended claimed condition "at least a part of the image of a particle does not move any more than it is contained substantially within the boundary of the same detection elements during two measurement periods" still allows, as submitted by the appellant, a portion of the image of a particle to move from one detector element to the adjacent one between two consecutive measurement periods and therefore still allows for a relatively low flow consistent with the teaching of the document. In particular, document D1 requires, as pointed out by the respondent, the detection of several images of the same particle at different positions as it moves, and this exposure regime can still be achieved with a flow satisfying the amended claimed condition.

Therefore, the amendment to claim 1 restricts the speed with which the liquid sample may flow, but does not exclude relatively low sample flows that the skilled person would consider in an obvious way when applying the teaching of document D1 (cf. point 2 above).

6. Fifth to eighth auxiliary requests - Inventive step

When compared with claim 1 of the main request (cf. point IV above),

- claim 1 of the fifth auxiliary request incorporates the amendments of claim 1 of the first and the third auxiliary requests,

- claim 1 of the sixth auxiliary request incorporates the amendments of claim 1 of the first, the second and the third auxiliary requests,

- claim 1 of the seventh auxiliary request incorporates the amendments of the first and the fourth auxiliary requests, and

- claim 1 of the eighth auxiliary request incorporates the amendments of claim 1 of the first, the second and the fourth auxiliary requests.

Since it was concluded in points 2 to 5 above that the subject-matter of claim 1 amended according to the first to fourth auxiliary requests does not involve an inventive step, the same conclusion applies to the various combinations of amendments defined in the subject-matter claim 1 of the fifth to eighth auxiliary requests (Articles 56 EPC).

7. Ninth auxiliary request - Admissibility - Remittal

7.1 The amended set of claims of the ninth auxiliary request was submitted during the oral proceedings in response to the discussion on the patentability of the previous claim requests as the Board showed reluctance to endorse the respondent's and opposition division's construction of the claimed feature "stand still during the exposure" as excluding a fluid sample flow. The appellant objected to the admission of the amended claim request into the proceedings at such a late stage of the proceedings. The appellant submitted in particular that the amendments addressed objections that had already been raised in the statement of grounds of appeal; in addition, the amendments gave rise to new issues under Articles 123(2), 123(3), 83 and 84 EPC and would also require a new analysis of the issues of novelty and inventive step, so that the proceedings might then have to be continued in writing, possibly after remittal of the case. According to the appellant, the admission of the amended claim request into the proceedings would, under these circumstances, be contrary to the provisions of Articles 13(1) and 13(3) RPBA (Rules of Procedure of the Boards of Appeal).

7.2 The Board notes that during the written proceedings, and in particular in the statement of grounds of appeal, the appellant had indeed already pointed out that according to the definition of the stand-still condition of the liquid sample given in the patent specification the particles might move. However, it was during the discussion at the oral proceedings that it became clear that the claimed feature "stand still during the exposure" did not only not exclude movement of the particles alone (as a consequence, for instance, of the thermal Brownian motion inherent to particles suspended in a fluid), but also did not exclude a flow of the volume of liquid sample which was relatively slow when compared with the exposure time, and that this latter issue was critical to the outcome of the case since it was at variance with the finding on which the decision under appeal was based (cf. point 2.1 above).

The set of claims of this request has been amended, inter alia, so that claim 1 now requires that the sample "is contained in [a] removable sample compartment before, during, and after assessment", and this amendment, in the Board's view, constituted a reasonable attempt to exclude measurement of the particles in a flow regime as required by document D1, and also a direct and legitimate reaction to the developments during the oral proceedings mentioned in the former paragraph.

Notwithstanding the appellant's objections against the formal admission into the proceedings of the amended claim request at such a late stage of the proceedings, the Board considered it fair and appropriate in the specific circumstances of the case to admit, despite of its late filing, the amended set of claims of the ninth auxiliary request into the proceedings. When admitting this claim request into the proceedings the Board was of the opinion that the amendments would not "raise issues which the Board or the other party or parties cannot reasonably be expected to deal with without adjournment of the oral proceedings" within the meaning of the provisions of Articles 13(1) and 13(3) RPBA, because it will be for the department of first instance to deal with the issues surrounding the amended claim request after remittal. In addition, even considering the present situation to be at variance with the aforementioned provisions, the Board notes that, as already acknowledged by other Boards (see for instance decision T 434/12, point 1.3 of the reasons, and decision T 671/08, point 7.5), the particular circumstances of a case may preclude a strict, purely literal application of the provisions of these two articles. As regards the present case, the right to fair procedure is one of the most important principles of procedural law generally recognized in the Contracting States and has therefore to be taken into account under Article 125 EPC, and this principle may prevail over the provisions of Article 13(3) RPBA because according to Article 23 RPBA the Rules of Procedure "shall be binding upon the Boards of Appeal, provided that they do not lead to a situation which would be incompatible with the spirit and purpose of the Convention".

7.3 During the oral proceedings the appellant, after closer consideration of the amendments made according to the ninth auxiliary request, indicated to be unprepared to discuss in detail the amended set of claims because new issues under Articles 84, 123(2) and 123(3) EPC emerged from the amendments and, more particularly, because the objections under Articles 100(b) and 83 EPC raised during the proceedings with regard to the previous claim requests would need to be reformulated and complemented in view of the amendments to claim 1. In addition, the amendments required a re-assessment of patentability as compared to the previous claim requests.

In view of the fact that the parties' case could not be adequately developed for the Board to satisfactorily decide on the different new issues as a sole instance, of the fact that the whole proceedings had been conducted in a speedy way (notice of opposition filed on 22 March 2012, interlocutory decision of the opposition division posted on 21 January 2013, and oral proceedings before the Board held on 27.05.2014), and of the respondent's request to proceed further in writing, the Board considered remittal, in the specific circumstances of the case, to be the most appropriate step from the point of view of both procedural fairness and efficiency. Accordingly, the Board decided to exercise its discretion under Article 111(1) EPC in remitting the case to the opposition division for further prosecution on the basis of the set of claims of the ninth auxiliary request.

8. Pending the outcome of the ninth auxiliary request, there was no need to deal with the tenth and eleventh auxiliary requests of the appellant.

9. With a letter dated 23 June 2014 the opponent requested amendment of the minutes of the oral proceedings before the Board. The Board notes that the present decision reflects the points raised in that request. The Board therefore sees no need to amend the minutes.