T 0039/82 (Light-reflecting slats) of 30.7.1982

Summary of Facts and Submissions

I. European patent application No. 79 105 112.1 filed on 12 December 1979 and published under publication No. 0 012 430, claiming the priority of a prior application of 12 December 1978 was refused by the decision of the Examining Division dated 15 October 1981. The decision was based on six patent claims submitted on 17 July 1981.

II. In the decision the Examining Division held that the teaching of the current Claim 1 did not involve any inventive step. In support of the decision it cited German patent specification 915 657, German unexamined application No. 2 634 522 and the published documentation of German utility model No. 1 863 517. The decisive factor in denying inventive step was that in Claim 1 protection is sought for the use of a measure known in the same special field, a use that had not involved overcoming any special technical difficulties.

III. The applicant lodged an appeal against this decision on 10 December 1981, with payment of the relevant fee, and set out the grounds of appeal in a letter submitted on 1 February 1982. The applicant adheres to the claims on which the refusal was based and is of the opinion that the subject-matter of Claim 1 is not obvious from the publications cited.

IV. In a communication of 30 April 1982 the applicant was notified that there were objections on formal grounds to the wording of patent Claims 1, 5 and 6.

V. The applicant submitted amended patent claims 1 to 6 and a correspondingly adapted description by letter of 30 June 1982, and applied for reversal of the contested decision and grant of a European patent on the basis of these documents together with the original drawings. Patent Claim 1 is worded as follows: "1. Device for the reduction of light-reflection on traffic lights caused by extraneous light, consisting of a plurality of slats (3) designed to absorb extraneous light impinging slantingly on their upper sides and disposed in front of the light source parallel to one another and spaced apart, characterised in that the upper sides (4) of the slats (3) confronting the source of extraneous light are designed to be strongly light-absorbing, the undersides (5) of the slats (3) on the other hand strongly light-reflecting."

VI. For the wording of the orginal patent claims and description, see publication No. 0 012 430.

Reasons for the Decision

1. The appeal complies with Articles 106 to 108 and Rule 64 EPC and is, therefore, admissible.

2. The features stated in the present patent Claim 1 were subject-matter of the original patent Claims 1 and 2 supported by the description (Art. 84 EPC). The subject-matter of the claim therefore does not extend beyond the content of the application as filed (Art. 123(2) EPC). In the preamble (prior art portion) of patent Claim 1 the applicant has stated all those features of the claimed subject-matter which in combination have become known through the documentation of German utility model No. 1 863 517 (Rule 29(1)(a) EPC). There are no objections to considering the device according to that publication to represent the prior art, since none of the devices investigated during examination of the application more closely resembles the subject-matter of Claim 1. There can be no objection to the change in term from "signal lights" to "traffic lights"; this results in a clearer expression of the special field in which the application lies. Patent Claim 1 thus meets the formal provisions of the Convention and is, therefore, not open to objection in that regard.

3. In the case of the device according to the documentation of German utility model No. 1 863 517, the surface of the slats placed at a distance from the light source of the traffic light to reduce the light-reflection caused by extraneous light is painted black on all sides. The slats consequently absorb an increasing proportion of signal light with increasing width and closeness of spacing. The applicant has regarded the resulting reduction in signal efficiency as disadvantageous.

4. The applicant is therefore based on the problem of improving the known device in such a manner that a higher signal efficiency is achieved while retaining the good suppression of extraneous-light reflection in the traffic light.

5. This problem is solved, without needing more detailed support, by the features stated in the characterising portion of Claim 1.

6. It is evident from the statements in Section 2 that the device according to Claim 1 differs from the device described in the German utility model 1 863 517 in the features stated in the characterising portion of the claim. These features are also not realised in US patent specification 2 616 957 cited in the search report. The louvre-type members of that device serving to reduce the extraneous-light reflection manifest a black-painted surface absorbing light on all sides. The subject-matter of Claim 1 has similarly not become known through the other publications cited (German patent specification 915 657, German unexamined application 2 634 522). This already follows from the fact that neither publication concerns a device for reduction of light-reflection caused by extraneous light in traffic signals such as traffic lights. The device according to Claim 1 is therefore new vis-à-vis the prior art.

7. It is therefore to be examined whether the subject-matter of Claim 1 is obvious in relation to that prior art.

7.1. The solution set down in the characterising portion of Claim 1 to the problem underlying the application (cf. Section 4) is based on the idea of utilising for signalling the proportion of signal light which is radiated upwards, i.e. away from the so-called observer half-space (the space in which the signal light must be detectable) and which in the case of the known device is absorbed at the undersides of the slats, by reflecting this proportion into the observer half-space. As proposed in the application, this idea is realised in that only the upper sides of the slats confronting the extraneous-light source are designed to be strongly light-absorbing, their undersides on the other hand strongly light reflecting. In this manner the loss of signal light caused by the absorption of the light rays directed downwards into the observer half-space but impinging on the upper sides of the slats is largely compensated and thus a higher proportion of light is effectively utilised than in the case of the known device.

7.2. The publications cited do not give the skilled person any indication that the signal efficiency may be increased by utilisation for signalling of the proportion of light absorbed at the underside of the slat in the case of the device according to the German utility model 1 863 517.

7.2.1. US patent specification 2 616 957, like the documentation of the above-mentioned utility model, supplies the teaching that the entire surface of the slats is to be made light-absorbing in the case of a device for reducing the light-reflection at traffic signals caused by extraneous light. Thus there is no thought of utilising the signal light impinging on the slats for signalling. For this purpose it is only intended to use the proportion of signal light passing between the slats in the direction of the observer half-space.

7.2.2. German unexamined application 2 634 522 concerns a signal lamp for motor vehicles. In this case the slats arranged in front of a reflector are similarly provided with a light-absorbing coating. Like the coating of the slats in the device according to US patent specification 2 616 957 it has the task of preventing a penetration of extraneous light. In the case of the known signal lamp, however, practically no signal light strikes the upper and undersides of the slats, since the reflector produces a beam of parallel signal light rays and the slats run at least approximately parallel to the rays. If for no other reason, this device could not suggest redesigning the slats of the device according to German utility model 1 863 517 in accordance with the characterising portion of Claim 1.

7.2.3. The subject-matter of German patent specification 915 657 is not a traffic signal but a headlight for motor vehicles. Whether this patent, as the contested decision considers, lies in the same special field as the subject-matter of the application, may be left open. Even if it is assumed to do so, it could not be suggestive for purposes of the subject-matter of Claim 1, for the headlight according to this patent specification addresses a different problem than the subject-matter of the application. The design proposed in the patent specification is intended to solve the problem of avoiding the switching from a light source at the focal point of the reflector to a weaker light source situated outside the focal point, necessary in conventional headlights for dipping of lights. This is achieved on dipping by diverting the light radiating from the light source at the focal point via slats having reflecting undersides. At the same time the view into the dipped headlight is obscured by a light-absorbing finish of the slat upper sides. Since this design of the slat upper and undersides, while also used in the subject-matter of the application, is intended to solve a problem other than the one underlying the subject-matter of Claim 1, the teaching of German patent specification 915 657, either alone or in conjunction with the teachings to be derived from the other publications, could not inspire proposal of the same measures for improvement of the signal efficiency in a traffic light.

7.3. From the foregoing considerations of what suggestions for the teaching of the characterising portion of Claim 1 were to be gleaned from the prior art, especially from German patent specification 915 657, it is evident that, contrary to the view taken in the contested decision, inventive step cannot be denied solely on the grounds that the measure forming this teaching was known before the priority date through a publication in the same special field as the subject-matter of the application. To arrive at a proper assessment of inventive step, it was also necessary to examine whether the prior art gave the skilled man an indication for applying this measure in the present case. Such an indication does not have to be given expressis verbis. It can reside in the fact that the purpose of the known measure in the known case is the same as in the case to be decided. It therefore had to be investigated what problems are solved in the known case and in the case in suit. Since this investigation revealed that the problems differ fundamentally from one another, that result had to be taken as proof that from the publication describing the measure it was as little obvious to the skilled person as from the remaining state of the art to use this measure in the different context provided for in the application. It was therefore without significance that, as in the opinion of the contested decision, no special difficulties had to be overcome in the use of this measure.

7.4. For the foregoing reasons the subject-matter of Claim 1 is based on an inventive step (Article 56 EPC). The claim is therefore allowable (Article 52 EPC)

8. The dependent Claims 2 to 6 have as subject-matter special embodiments of the invention according to Claim 1 and are therefore likewise allowable.

9. The changes in the description serve to take into account the prior art as in German utility model 1 863 577 and for the clear presentation of the problem task and the invention or for the introduction of uniform terms for the same component. They are therefore not open to objection.

ORDER

For these reasons, it is decided that:

1. The decision contested is set aside.

2. The case is remitted to the Examining Division with the order to grant the European patent applied for on the basis of the documents (six patent claims and description) submitted on 30 June 1982 and the original drawings.