T 0087/01 11-09-2003

1. The appeal is admissible.

Main request - Claim 1 for DE and GB

2. Document D1 was published after the date of filing of the opposed patent. It is common ground that D1 forms part of the state of the art under Article 54(3) EPC regarding claim 1 for DE and GB of the main request. It is likewise not contested by the proprietor that D1 discloses an optical pickup which according to the embodiment of realisation of figures 12 and 13. (see column 9, line 21 to column 10, line 35) comprises all the features set out in claim 1 for DE and GB of the main request, except feature (c) according to which an object lens (5) is disposed in front of an optical disk (6) for focusing three light beams coming from a splitting means on the signal surface of the optical disk (6).

2.1. An optical pickup in which diffraction means are disposed between splitting means and an object lens is only supported by the embodiment of realisation disclosed in the patent in suit with reference to Figure 2. According to this embodiment, the light beam emitted by the laser diode is split by a diffraction grating (splitting means 2) into three light beams which are transmitted to diffracting means (hologram 10) and then focused by the object lens. Accordingly, feature (c) of claim 1 for DE and GB of the main request cannot be interpreted on the basis of the description of the patent as restricted to an object lens which focuses three light beams directly coming from the splitting means of the pickup, but it more generally covers an object lens which focuses on an optical disk three light beams split by said splitting means (2). The pickup according to claim 1 and the pickup disclosed by D1 must be interpreted in the same way. Therefore, the embodiment of Figures 12 and 13 of D1, in which the three light beams split by the diffraction grating (4a) are transmitted to the objective lens (6) via both the hologram (3) and the collimating lens (5) for focusing on the optical disk (7), should be understood as disclosing an optical pickup in which the objective lens (6) focuses on the surface of the disk the three light beams coming from the splitting means (4a).

2.2. There is nothing in the patent for supporting the proprietor's allegations that according to claim 1 the split main beam was not influenced by the hologram (10) and the split first order beams were not imaged on the disk. It is irrelevant, contrary to the proprietor's view, that the objective lens (6) in Figure 13 of D1 focuses on the optical disk the beams made parallel by the collimating lens (5). Accordingly, D1 discloses an optical pickup comprising feature (c) of claim 1 for DE and GB of the main request. This claim thus lacks novelty (Article 54(3) EPC).

First auxiliary request - Claim 1 for DE and GB

3. Claim 1 for DE and GB of the first auxiliary request merely differs from claim 1 for DE and GB of the main request in that the expression "an object lens" has been replaced by the expression "a single object lens". In the embodiment of Figures 12 and 13 of D1, the lens (5) is a collimating lens which renders parallel the three light beams passing therethrough and the three beams formed by the diffraction means (4a) are only focused on the surface of the optical disk (7) by the single objective lens (6). Accordingly, claim 1 for DE and GB of the first auxiliary request lacks novelty for the same reasons as those given in respect of claim 1 for DE and GB of the main request.

Second auxiliary request - Claim 1 for DE and GB

4. Claim 1 for DE and GB of the second auxiliary request differs in substance from claim 1 as granted in that the feature according to which the diffraction means are "disposed between said splitting means (2) and said object lens" are replaced by the feature "said splitting means (15B) is disposed between said diffraction means (15A) and said object lens (5)". Claim 1 for DE and GB of the second auxiliary request thus corresponds to the optical pickup described in the embodiment of realisation according to Figure 5 of both the application as originally filed and the patent in suit. However the subject-matter of this claim does not result from a limitation of the subject-matter of claim 1 as granted.

4.1. The proprietor, referring to the Case Law of the Boards of Appeal (T 108/91, OJ 1994, 228, and non published decisions T 31/93, T 774/97, T 1011/96, T 762/95 and T 116/99), argued that claim 1 for DE and GB of the second auxiliary request did not contravene Article 123(3) EPC because, in view of Article 69 EPC and its Protocol on Interpretation, the skilled person reading together the description and claim 1 of the patent in suit would understand that said claim covered the optical pickup according to the embodiment shown in Figure 5 of the patent.

4.2. In decisions T 108/91 and T 31/93 (point 2), a feature included in claim 1 during the examination proceedings did not correspond to what was originally disclosed. It was immediately apparent that what was defined in granted claim 1 when interpreted on the basis of the description and drawings could not be that for which protection was sought. The replacement of the incorrect feature by the correct one was considered, on a fair interpretation of the claim in the light of the totality of the disclosure, as not extending the protection. In decisions T 774/97 (point 4) and T 1011/96 (point 2), claim 1 as granted contains unclear expressions. The Board considered that the amendments made in appeal proceedings solely serving to remove inconsistencies between the subject-matter of the granted claim and the accompanying description did not infringe Article 123(3) EPC. According to decision T 762/95 (point 2), no extension of the protection conferred resulted from the correction of an inconsistency in a granted claim if the correction was either apparent from the claim itself or from the true construction of the claim in the context of the specification. According to decision T 116/99 (point 2), the scope of a claim must be assessed taking into account not only the claims but also the description and the drawings. Interpreted in this way, the amendments to claim 1 as granted (which covered a fuel additive per se) to specify a fuel composition comprising the additive did not extend the protection conferred.

4.3. In the present case, claim 1 as granted results from the combination of claims 1 to 4 as originally filed and its subject-matter is clearly understandable in itself without needing any interpretation on the basis of the description. It is true however that the optical pickup specified in claim 1 as granted is supported neither by the example of realisation according to Figure 2 of the patent, from which it differs by the restriction that the splitting means is formed on a second surface of a hologram, nor by the example of realisation according to Figure 5 of the patent, which shows an inverted disposition of the splitting means and the hologram in respect of the object lens.

4.4. However, in the present case, which is distinguishable from the situation in the decisions cited by the proprietor, it is not immediately apparent to the skilled reader that the optical pickup according granted claim 1, which corresponds to the subject-matter of originally filed claim 4 as dependent on originally filed claims 1 to 3, does not correspond to the pickup for which protection was sought. Nor is it immediately apparent which one of the two described embodiments of optical pickups the proprietor might have intended to protect. Accordingly, the Board judges that claim 1 as granted would be understood by the skilled reader as specifying the optical pickup identified by its own wording and should not be interpreted as covering the embodiment of realisation of Figure 5 of the patent in suit. Claim 1 for DE and GB of the second auxiliary request thus extends the protection conferred by the patent as granted.

4.5. In decision G 1/93 (OJ 1994, 541), the Enlarged Board of Appeal pronouncing on the question of "limiting extensions" observed that "Article 123(3) EPC is directly aimed at protecting the interests of third parties by prohibiting any broadening of the claims of a granted patent, even if there should be a basis for such a broadening in the application as filed" and that "the ultimate responsibility for any amendment of a patent application (or a patent) always remains that of the applicant (or the patentee)" and judged that even in the case of "limiting extensions" a patent which infringes Article 123(3) had to be revoked. In the present case, granted claim 1 does not contain a "limiting extension". The Board however sees no good reason in the fact that its subject- matter may be different from what the proprietor declared he had intended to cover for adopting a less strict attitude than in the case of "limiting extensions". Accordingly, claim 1 for DE and GB of the second auxiliary request is not acceptable.

Third auxiliary request

5. Claim 1 for FR only of the third auxiliary request is identical to claim 1 as granted. According to the appellant, the conventional three-beam-type optical pickup described in the patent in suit (column 1, lines 6 to 43) with reference to Figure 1 forms the closest prior art.

5.1. The proprietor stated during the oral proceedings that the optical pickup according to Figure 1 of the patent was merely cited as the background art in view of Rule 27(1)b EPC and corresponded to internal prior art which was not public at the filing date of the patent.

5.2. The Board observes that the prior art according to Figure 1 was described in the patent as a conventional three- beam-type optical pickup. The skilled reader will thus understand from the patent that this pickup has been used or produced on such a scale that it had become conventional before the filing date of the application for the present patent and thus formed part of the general knowledge of the skilled person. The Board considers that the retraction of the proprietor at a late stage of the appeal proceedings, during the oral proceedings, is unfair and deprives the appellant, who had been relying on the truth of the disclosure that Figure 1 of the patent showed prior art, of the possibility of searching for a published document disclosing a pickup according to Figure 1. The Board judges therefore that the prior art according to Figure 1 of the patent, which was cited and acknowledged in the patent as the closest prior art for the purpose of formulating the technical problem set out in the description, forms the correct starting point for the assessment of the invention and can be used for assessing inventive step, at least for the purposes of this decision.

6. According to the prior art of Figure 1 of the patent, a conventional three-beam-type optical pickup comprises the following features of claim 1:

- a laser source (diode 1) for emitting a laser light beam,

- a diffraction grating (2) for splitting said laser beam into three light beams,

- an object lens (5) for focusing the three light beams coming from the diffraction grating on the surface of an optical disk (6) and

- a photodetector assembly (9) for detecting the light beams reflected from the surface of the disk.

6.1. In contrast with the pickup set out in claim 1, the three light beams reflected on the surface of disk are according to Figure 1 deflected by a beam splitter (3), and not by diffraction means, towards the photodetector assembly; and said diffraction grating and diffraction means are not formed on respective surfaces of a hologram.

6.2. According to description of the patent (column 1, lines 44 to 54), the high number of optical elements used in the prior art of Figure 1 renders the conventional pickup bulky and costly, not easy to miniaturize and adjust. Starting from this prior art the objective problem addressed by the invention can thus be seen as providing a three-beam optical pickup which remedies these drawbacks. According to claim 1, the problem is solved by using a first surface of a hologram constituting a diffraction means for diffracting the light beams reflected from the surface of the disk, forming the splitting means on the second surface of the hologram and disposing the diffraction means between the splitting means and the object lens.

7. D2 (Figure 4; column 9, line 29 to column 10, line 22 and column 11, lines 20 to 35) discloses an optical pickup in which a holographic diffraction grating (75) receives the beam emitted by a laser source (43) to produce a zeroth-order diffracted beam which is focused by an objective lens (44) on the surface of an optical disk (41). The diffraction grating is responsive to the beam reflected from the disk (via the objective lens) to produce a plurality of sidewards diffracted beams directed to a detector assembly (45). This pickup is an improvement to a bulky and heavy prior art pickup (Figure 1 of D2) in which the light beam reflected from the disk was split by wedge prisms (51, 52) into two beams directed to the detector assembly (column 2, lines 10 to 19; column 6, lines 12 to 53).

8. According to the appellant, the skilled man starting from the prior art according to Figure 1 of the patent would immediately recognize that the technical problem, namely replacing a bulky and costly optical assembly in an optical pickup, is the same as the technical problem solved by the pickup of Figure 4 in D2 in view of its own prior art (Figure 1 of D2). It would then be obvious to replace the splitter (3) and the lenses (7 and 8) in the prior art pickup of figure 1 of the patent by the diffraction grating (75) of D2 and to arrive at the optical pickup of claim 1. The Board cannot share the appellant's view.

8.1. In Figure 1 of the patent, three light beams are focused on, and reflected from, the surface of the optical disk. The beam splitter (3) is used to transmit to the object lens the three light beams coming from the splitting means, and to reflect the three light beams reflected from the disk through the lenses (7 and 8) to form spots on the detector assembly. In contrast with that, according to D2 one, and only one, light beam is focused on, and reflected from, the disk. The diffraction means (75) in D2 are configured so as to produce and transmit to the objective lens a zeroth-order diffraction beam and are responsive to the single light beam reflected from the optical disk to produce a plurality of sidewards diffracted beams.

8.2. It is clear that the straightforward replacement of the beam splitter (3) and the lenses (7 and 8) in the prior art of Figure 1 of the patent by the diffraction grating of D2 would not, by itself, result in a hologram as specified in features (f) and (g) of claim 1, whose first and second surfaces respectively constitute diffraction means and splitting means.

8.3. Thus, the combination of the prior art according to Figure 1 of the patent with the teaching of D2 does not lead to the optical pickup set out in claim 1, and does not render it obvious.

9. Accordingly, the arguments of the appellant have not convinced the Board that the subject-matter of claim 1 for FR only of the third auxiliary request was obvious to the person skilled in the art. The Board therefore concludes that the subject-matter of this claim shall be considered as involving an inventive step within the meaning of Article 56 EPC.

10. In the Board's judgement, the patent in suit, in the version for FR only, and the invention to which it relates satisfy the requirements of the Convention.