T 1001/16 27-10-2017

1. The appeal is admissible.

2. Definition of the invention

2.1 The invention concerns a dental panoramic x-ray imaging system having an x-ray source and an imaging device which move around the patient's head according to a predetermined geometric path and speed profile (paragraph [0010] of the patent; Figure 3). The movement is such that an image of a predetermined layer of interest is formed. The invention allows the x-ray scan to be performed by moving the x-ray source and imaging device in a continuous movement around the patient's head (paragraph [0030]).

2.2 The movement is defined in claim 1 (feature (c)) by specifying a "rotational axis around which at least one of the x-ray source and imaging device is adapted to rotate along a spline, which is a non-circular trajectory, ...". Whilst the patent as granted already defined the motion "... along a spline", the feature "which is a non-circular trajectory" was added during opposition proceedings.

It is common general knowledge that a "spline" is a continuous curve having continuous derivatives. This concept corresponds, for example, to the definition in the Shorter Oxford English Dictionary (E1) and the Wikipedia article "Spline (mathematics)" filed with the statement of grounds of appeal. In essence, "spline" designates a smooth curve, without sharp turns or kinks (as in a "V"-shaped curve).

As explained in the patent as granted (page 8, lines 26 to 28), the movement along a spline can be either a circular or a non-circular trajectory, and in the presently pursued claims 1 the movement of the x-ray source and imaging device is limited to a non-circular trajectory. Hence, the claimed expression of "a spline, which is a non-circular trajectory" can be given no meaningful reading other than that of a non-circular spline trajectory.

3. Main request

3.1 Priority right

3.1.1 It is undisputed by the parties that application US 11/277,530, from which the patent claims its priority, is represented by document D3. It is likewise undisputed that if the claim to priority fails, D3 is comprised in the state of the art within the meaning of Article 54(2) EPC (as it was published on 14 September 2006, before the 10 November 2006 filing date of the application leading to the patent in suit) and that, in that case, D3 is novelty-destroying.

3.1.2 What was disputed, however, is whether priority could be validly claimed from D3, since the same applicant had already disclosed the same invention in the earlier previous application US 60/677,020 (USPRE). USPRE had been filed on 2 May 2005, i.e. before the 27 March 2006 filing date of D3 and about 18 months before the 10 November 2006 filing date of the application leading to the patent in suit.

3.1.3 According to Article 87(1) EPC, only the first applicaton filed in a state party to the Paris Convention or a member of the WTO can form the basis for a priority right. Therefore, if apart from the application whose priority is being claimed in the patent (in this case D3), an earlier previous application had also been filed (in this case USPRE), in order to check the validity of the priority claim it must be established whether the invention claimed in the patent was already disclosed in the earlier previous application (USPRE).

To establish whether the invention claimed in the patent was already disclosed in the earlier previous application, USPRE, the same principles have to be applied as when establishing identity of invention between the application forming the basis for priority and the application claiming priority. The question is whether the person skilled in the art could derive the subject-matter of the claim of the patent directly and unambiguously, using common general knowledge, from the earlier previous application USPRE (G 2/98, OJ 2001, 413). As confirmed in G 1/03, point 4 of the Reasons, the disclosure as the basis for the right to priority under Article 87(1) EPC and as the basis for amendments to an application under Article 123(2) EPC has to be interpreted in the same way.

3.1.4 The respondent disputed that USPRE directly and unambiguously disclosed that the trajectory of the x-ray source and imaging device was a non-circular spline trajectory.

3.1.5 In the Board's view such a trajectory is disclosed in USPRE for the following reasons:

USPRE discloses in claim 1 that the x-ray source and imaging device rotate on a circular or non-circular trajectory. USPRE does not explicitly mention that the trajectory is a spline, i.e. essentially a smooth curve without sharp turns or kinks, as explained under point 2.2 above.

However, the Board considers that from what is disclosed on page 16, paragraphs 4 and 5 in connection with Figure 7, such a trajectory inevitably occurs in USPRE as well. This passage explains that a transversal layer is obtained, the layer being transversal to the panoramic images which follow the contour of the jaw and parallel to the direction of radiation. Thus, the direction of radiation will be perpendicular to the panoramic images or layers which are illustrated in Figure 7. This is what Figure 3 illustrates too, albeit with reference to prior-art orthopantomographs (OPG), in which the perpendicularity of the centre of the x-ray beam to the panoramic layer is expressly indicated by a graphical symbol denoting perpendicularity. Moreover, in the description of Figure 3, on page 3, paragraphs 4 and 5, it is mentioned that the movement of the x-ray source and imaging device is synchronised so that the imaging device surface normal is perpendicular to the layer of interest, i.e. the panoramic layer.

The respondent held the view that USPRE disclosed on page 16, paragraph 5, that the transversal layer did not have to be strictly parallel to the direction of radiation, but could be just "close to parallel". In the Board's view, this possibility (mentioned in parentheses after the feature "parallel") addresses the fact that for a fan-type x-ray beam, as depicted in Figure 3, only the center ray will be strictly perpendicular to the panoramic layer, while the rays of the periphery of the beam will be only substantially perpendicular to it.

The jaw of a patient has a roughly horseshoe-shaped contour, which is clearly non-circular, particularly in its lateral portions. Hence, if a circular trajectory of the x-ray source and imaging device were used, as suggested by the respondent, the direction of the x-rays would not be perpendicular to the panoramic layers which follow the contour of the jaw. Moreover, the panoramic layers shown in Figure 7 of USPRE, as well as in Figure 3, are undoubtedly smooth curves without sharp turns or kinks, thus having continuous derivatives. Hence, since the x-rays are emitted perpendicularly to these curves, the x-ray source and imaging device will likewise move along a smooth trajectory.

3.1.6 The Board therefore finds that from the explicit direct and unambiguous disclosure of the movement of the x-ray source and imaging device in USPRE, the skilled person would conclude that the movement inevitably occurs along a non-circular spline. This is consequently no new information over what is explicitly disclosed. The respondent has identified no other feature in claim 1 of the main request which goes beyond the subject-matter disclosed in USPRE.

3.1.7 As the person skilled in the art derives the subject-matter of claim 1 of the main request directly and unambiguously, using common general knowledge, from the earlier previous application USPRE, D3 is not the first application within the meaning of Article 87(1) EPC and thus does not form the basis for a priority right.

Consequently, D3 is comprised in the state of the art within the meaning of Article 54(2) EPC.

3.2 Novelty

As it is undisputed that D3 discloses the subject-matter of claim 1 of the main request, the novelty requirement of Article 54(1) EPC is not fulfilled.

4. Auxiliary request 2

4.1 Claim 1 of auxiliary request 2 adds to claim 1 of the main request the limitation that "the x-ray imaging device (14) is adapted to produce at least 50 frames per second".

4.2 However, this feature too is directly and unambiguously derivable from USPRE.

Claim 14 of USPRE specifies an open-ended range of at least 30 frames per second (fps). Furthermore, in the last paragraph of page 11, USPRE provides further information on the frame rates the imaging device should achieve and points the reader in this precise context directly to the imaging devices disclosed in document D10 which it explicitly "incorporates by reference". Consequently, the Board considers that at least those aspects concerning the frame rate of the imaging device disclosed in D10 are to be seen as being part of the content of USPRE. In particular, D10 discloses frame rates of 50 fps, 100 fps and 400 fps (page 5, lines 17 to 20).

Given that USPRE discloses an open-ended range of at least 30 fps and the discrete value of 50 fps, the range of at least 50 fps is likewise disclosed.

4.3 It follows, similarly to the conclusions for the main request, that the subject-matter of claim 1 of auxiliary request 2 is directly and unambiguously derivable from the earlier previous application USPRE, so that D3 is not the first application within the meaning of Article 87(1) EPC and does not form a basis for a priority right. Thus, D3 is comprised in the state of the art within the meaning of Article 54(2) EPC and is undisputedly novelty-destroying.

The novelty requirement of Article 54(1) EPC is therefore not fulfilled.

5. Auxiliary request 5

5.1 Claim 1 of auxiliary request 5 adds to claim 1 of the main request the limitation that "the x-ray imaging device (14) is adapted to produce more than 300 frames per second".

5.2 However, this feature too is directly and unambiguously derivable from USPRE.

According to claim 16 of USPRE, the imaging device produces frame rates of at least 300 fps, which is equivalent to stating the frame rate to be 300 fps or more than 300 fps. The latter of these alternatives is what claim 1 of auxiliary request 5 specifies.

5.3 It follows, similarly to the conclusions for the preceding requests, that the subject-matter of claim 1 of auxiliary request 5 is directly and unambiguously derivable from the earlier previous application USPRE, so that D3 is not the first application within the meaning of Article 87(1) EPC and does not form a basis for a priority right. Thus, D3 is comprised in the state of the art within the meaning of Article 54(2) EPC and is undisputedly novelty-destroying.

The novelty requirement of Article 54(1) EPC is therefore not fulfilled.