T 0653/91 24-09-1992

Summary of Facts and Submissions

I. The Appellant is proprietor of European patent No. 0 121 216.

Claims 1 and 5 of this patent are independent ones, the latter reading -

"5. An X-ray television diagnostic apparatus (200) for examining an object, comprising:

- a first source (1L) for generating first pulsatory X- rays delivered to the object to produce first pulsed X-ray images;

- first imaging means (4L) for receiving said first pulsatory X-ray images and converting said first X-ray images to corresponding first optical images;

- first television means (5L), including a television camera having a target that is scanned, for producing first analog video signals representative of said first optical images;

- a second source (1R) for generating second pulsatory X- rays delivered to the object to produce second pulsed X- ray images;

- second imaging means (4R) for receiving said second pulsatory X-ray images and converting said second X-ray images to corresponding second optical images;

- second television means (5R), including a television camera having a target that is scanned, for producing second analog video signals representative of said second optical images;

- synchronizing means (17) for generating field sync signals for synchronizing the scanning of said television cameras; and

- exposure control means (120, 110) responsive to said field sync signals for generating first and second X-ray control signals (SP-L, SP-R) so as to cause said sources to emit said pulsatory X-rays with a predetermined exposure time;

characterized by

- first imaging control means (130L) for generating first image blanking signals for said first imaging means (4L) so as to cause said corresponding first optical images to be delivered to said first television means (5L) only during the period in which said first X-ray control signal (SP-L) is being generated,

- second imaging control means (130R) for generating second image blanking signals for said second imaging means (4R) so as to cause said corresponding second optical images to be delivered to said second television means (5R) only during the period in which said second X- ray control signal (SP-R) is being generated;

- first television control means (6L) for generating first field blanking signals in correspondence to said first X-ray control signals so as to cause said first television means (5L) to be blanked out during emission of said first X-rays by said first X-ray source (1L),

- second television control means (6R) for generating second field blanking signals in correspondence to said second X-ray control signals so as to cause said second television means (5R) to be blanked out during emission of said second X-rays by said second X-ray source (1R), and

- video selecting means (140) for selecting first and second analogue video signals that are alternately derived from the first and second television means (5L;5R), respectively,"

a minor clerical error in the reference number of the first X-ray source being corrected here.

Claims 2 to 4 are appended to Claim 1 and Claims 6 to 8 are appended to Claim 5, whereas Claim 9 is appended to Claim 1 or 5.

II. The patent was opposed by the Respondent on the grounds mentioned in Article 100(a) EPC, referring inter alia to the prior art which can be derived from documents

D1: US-A-4 355 331 (already cited in the European patent) & DE-A-3 201 658;

D2: DE-A-1 920 003;

D3: DE-A-2 523 886.

III. Oral proceedings were held on 14 May 1991, at the end of which the Chairman of the Opposition Division announced the decision that the European patent was revoked. The written decision was issued on 25 June 1991.

IV. An appeal against this decision was lodged by the Appellant. With his Statement of grounds of appeal, the Appellant submitted on 28 October 1991 a new Claim 1 to replace Claim 1 according to his former main and auxiliary requests.

This new Claim 1 reads:

"1. An X-ray television diagnostic apparatus (100) for examining an object, comprising:

a source (1) for generating pulsatory X-rays delivered to the object to produce pulsed X-ray images;

imaging means (4) for receiving said pulsatory X-ray images and converting said X-ray images to corresponding optical images;

television means (5), including a television camera having a target that is scanned, for producing analog video signals representative of said optical images;

synchronizing means (17) for generating field sync signals for synchronizing the scanning of said television camera;

and

exposure control means (13, 14) responsive to said field sync signals for generating X-ray control signals (SP) so as to cause said source to emit said pulsatory X-rays with a predetermined exposure time;

characterized by

imaging control means (18) for generating image blanking signals for blanking an image intensifier (3) of said imaging means (3, 4) so as to cause said corresponding optical images to be delivered to said television means (5) only during the period in which said X-ray control signal (SP) is being generated; and

television control means (6) for generating field blanking signals in correspondence to said X-ray control signals (SP) so as to cause said television means (5) to be blanked out during emission of said X-rays by said X-ray source (1) and for starting the scanning of the television means after switching off the X-ray control signals (SP)."

V. The Respondent substantially commented on the Appellant's submissions as follows:

An apparatus as defined in the pre-characterising part of Claim 1 is disclosed in (D1). According to that illustration of prior art, television control means (30) and synchronising means (23) allow camera target scanning after X-rays generation and image intensifier blanking. Therefore, the second characterising clause of Claim 1 too is known from (D1). Besides, the fact that the opening of the "obturator" is longer than the X-ray impulse in the known device is not important for it does not influence the formation of after images.

Document (D2) too describes a diagnostic apparatus according to the pre-characterising part of Claim 1. In that apparatus, the image intensifier can only be operated during the emission of an X-ray pulse. Image fluctuations produced by the trailing edge of the fluorescent image or by cable capacity are thereby prevented. Therefore, the first characterising clause of Claim 1 is rendered obvious by document (D2).

Likewise, the characterising parts of Claims 2 and 3 are also rendered obvious by document (D2), whereas the features recited in Claim 4 are known from (D1). Consequently, none of the Claims 1 to 4 involves an inventive step.

Now, the provision of two imaging arrangements is known from document (D3). Claim 5, therefore, is not allowable in view of the prior art disclosed in documents (D1) to (D3). The same applies to Claims 6 and 8, which substantially correspond to Claims 2 and 4. The characterising features of Claim 7 are known from documents (D1) and (D2) and, finally, it is common practice to provide injector means in diagnostic apparatus for angiography. Therefore, Claims 5 to 9 too lack an inventive step.

VI. In a communication pursuant to Article 11(2) of the RPBA, the Board took the provisional view that, with consideration to the state of the art disclosed in documents (D1) to (D3), none of the independent claims submitted by the Appellant appeared to involve an inventive step.

VII. Both parties requested oral proceedings, which were duly appointed for 24 September 1992. Following telephone conversations shortly before that date, the Board was notified by fax on the day of the hearing that the Respondent's Representative would not attend the hearing.

During the hearing the Appellant requested that the decision under appeal be set aside and that the European patent be maintained in amended form according to his main request, i.e. on the basis of Claim 1 as submitted with his Statement of grounds of appeal, Claim 2 as amended during the oral proceedings of 14 May 1991 and Claims 3 to 9 as granted.

VIII. In support of his request, the Appellant substantially argued as follows:

In the claimed X-ray television diagnostic apparatus, the optical images are delivered to the television means (5) only when the X-ray control signal (SP) is generated, the television means (5) are blanked out during X-ray emission and scanning is performed after the X-ray control signal (SP) has been switched off. No afterglow image, therefore, is included in the X-ray image.

In the X-ray television diagnostic apparatus known from (D2), however, the camera (13) is operated continuously. Therefore, document (D2) does not disclose an apparatus in which an image intensifier is blanked out only during the generation of an X-ray control signal, and in which a television camera starts scanning after the control signal has been switched off. For this reason, combining the teachings of documents (D1) and (D2) does not lead to the present invention.

IX. At the end of the oral proceedings, the Chairman announced the decision that the decision of the Opposition Division was confirmed having regard to the main request filed on 28 October 1991, and that the appeal was dismissed.