T 1369/18 14-04-2021

Reasons for the Decision

1. The appellant-opponent's request for oral proceedings filed with its grounds of appeal was withdrawn with letter dated 24 February 2021 such that the present decision could be taken without holding oral proceedings.

Main request

Admittance of the request during oral proceedings in opposition

2. The main request corresponds to auxiliary request 2 filed during oral proceedings in opposition and admitted by the opposition division.

2.1 The appellant argued that the auxiliary request 2 should not have been admitted in opposition proceedings since it was late filed and did not meet the criterion of convergency of the auxiliary requests (having regard to auxiliary request 1).

2.2 The decision to admit auxiliary request 2 was a discretionary decision of the opposition division. As regards discretionary decisions, the Board should only examine whether the opposition decision exercised its discretion in a reasonable manner and applying the correct criteria. It is generally not the function of a board of appeal to review all the facts and circumstances of the case as if it were in the place of the department of first instance, in order to decide whether or not it would have exercised such discretion in the same way.

2.3 The opposition division considered convergency as one of the suitable criteria as is reflected by the minutes of the oral proceedings under section 7 and point 2.5.1 of the appealed decision, but came to the conclusion that strict convergency was not already required for the first and second auxiliary requests but usually for later ones.

The opposition division further concluded that the auxiliary request 2 could not be considered as an unexpectable development of the proceedings since it was based on a combination of granted claims and corresponded to auxiliary request 02 filed about a year before the oral proceedings.

2.4 In the Board's view, the opposition division correctly exercised its discretionary power by not strictly applying solely the criterion of convergency of the requests, but in considering and weighing other criteria, in particular the state of the proceedings and whether the other party was taken by surprise.

2.5 The Board hence sees no reason to overrule the discretionary decision of the opposition division to admit the auxiliary request 2 during oral proceedings.

Amendments (Article 123(2) EPC)

3. The main request complies with the requirements of Article 123(2) EPC.

3.1 Claim 1 of the main request is based on a combination of originally filed claims 1, 9 and 10. The wording was however slightly amended to bring the independent claim into the two-part form.

3.2 The appellant argued that in the first line of the characterizing portion of claim 1, the expression "said first and second angle are such that" implied that both angles alpha and beta influenced the direction of the reflected light, whereas in the application as originally filed, it was only the first angle beta that had an influence on the direction of reflected light.

3.3 This opinion is not shared by the Board since the second angle alpha is not an angle which value has to be chosen in order to achieve the result that the first and second optical axis are essentially perpendicular. In fact, the second angle alpha is identical to the angle between said first and second optical axis.

3.3.1 This derives directly from the wording of claim 1 that defines that light is emitted along a first optical axis. The emitted light rays are then reflected in a direction forming with the first optical axis a second angle alpha, whereby the reflected light rays follow a second optical axis which is essentially perpendicular to the first optical axis. As a consequence, the second angle alpha must be identical to the angle between the first and second optical axis.

3.3.2 The appellant argued that the term "perpendicular" referred to the angle between the first and second optical axis but not to the angle alpha. Angle alpha in his understanding had not just one value but referred to the plurality of light rays each having a slightly different direction forming thus a fan-like shape and each having a (different) angle alpha.

3.3.3 However, claim 1 refers to light rays being reflected "in a direction forming with the first optical axis a second angle alpha of a preset size", the claim thus referring to the direction and angle in singular. Claim 1 hence does not define that the reflected light shall be directed in a plurality of different directions whereby each direction forms a different angle alpha with the first optical axis, but the reflected light shall be rather combined into a bundle of more or less parallel light rays having a common axis (second optical axis B). This common axis shall form an angle alpha with the first optical axis whereby the angle alpha shall be essentially perpendicular.

3.3.4 The angle alpha is hence not an angle which value can be chosen but is the angle resulting from a choice of the angle beta between the two reflecting surfaces, the geometry of the reflecting surfaces (bent, flat etc.) and the orientation of the reflecting surfaces relative to the light source (whereby no angle is defined in the application that could be used for a definition of the orientation of the reflecting surfaces). The expression used in claim 1 of the main request is therefore identical in content with the expression used in claim 1 as originally filed.

3.3.5 This amendment hence complies with the requirements of Article 123(2) EPC.

3.4 The appellant further argued that replacing the term "approximately perpendicular" by "essentially perpendicular" resulted in another unallowable amendment.

3.4.1 This is also not shared by the Board because the term "essentially perpendicular" is already used in the application as originally filed (see paragraph [0020] of the application as published) when describing the orientation of the second optical axis with respect to the first optical axis, i. e. in the same context as in claim 1 of the main request.

3.4.2 This amendment hence also complies with the requirements of Article 123(2) EPC.

Insufficiency of disclosure (Article 83 EPC)

4. The patent provides sufficient information for the person skilled in the art of lighting systems to carry out the invention.

4.1 The appellant argues that no information is given on how to measure the angle beta and therefore the skilled person is not able to carry out the invention.

4.2 In this respect the Board fully agrees with the reasoning of the Opposition Division in the contested decision, see point 2.3.1, and makes it as its own.

It worth to note here, that the patent discloses in figures 1a an embodiment with two reflecting surfaces 3, 4 indicating the angle beta as the angle between the two lower edges of the first and second reflecting surface, i.e. the angle beta is the angle formed at the junction of the two reflecting surfaces and comprised between them as pointed out by the respondent. Hence, the angle to be measured is the angle comprised between the two tangents of the curves representing the reflecting surfaces at their point of intersection. Although other methods might by used to measure the angle between surfaces, such as the "method of the medium planes" as submitted by the appellant, these other methods do not correspond to the disclosure of the patent in suit.

Novelty (Article 54 EPC)

5. The subject-matter of claim 1 is novel in the sense of Article 54 EPC.

5.1 The appellant alleges that document D3 anticipates the subject-matter of claim 1.

5.2 D3 discloses in figure 10 a reflector that receives light from the source (41) in a first direction perpendicular to the surface (43), forming thus a first optical axis. This light is reflected by the reflector (40) having four sections. The adjacent sections form an angle different from 180° at the edges where the sections meet (otherwise there would be no bent in the surface of the reflector).

Since the reflector covers approximately half of the semisphere above the surface (43) and the light source is approximately in the centre of the semi-sphere, the amount of light reflected by the reflector is about half of the light emitted by the light source. Assuming that the light is evenly distributed amongst the four sections, each section receives about 12,5% as correctly estimated by the opposition division.

Each of the sections of the reflector therefore receives a "substantial portion" of the light rays emitted by the light source.

5.2.1 The term "substantial portion" refers in the Board's understanding to an amount of reflected light that is large enough such that it cannot be disregarded. The term "substantial portion" however does not mean "more of the light is captured than lost" nor refers to a specific minimum value for the amount of reflected light. A substantial portion can already be an amount of only 10% of the emitted light or even less ? this depends on the particular circumferences.

A reflector covering approximately half of the semi-sphere above the light source will however in any case reflect a substantial portion of the light rays and thus falls under the wording of the claim.

5.2.2 Covering half of the semi-sphere furthermore corresponds to covering a solid angle being approximately pi steradians, which is however not "greater than pi steradians" as required by claim 1.

5.2.3 The amount of about 12,5% per section furthermore results in about 25% of the light rays being emitted by the source of light intercepting the first and second reflecting surfaces, which is less than "at least 30%" as required by claim 1.

5.3 Figure 7 of D3 discloses an alternative reflector, using only two sections meeting at an edge (30CL). Following the same reasoning as set out with respect to figure 10, these sections will receive about 25% of the emitted radiation each, which again is a substantial portion of the light emitted by the light source.

The first and second reflecting surfaces hence intercept about 50% of the light rays emitted by the light source which is indeed "at least 30%".

5.4 The light leaves the reflector(s) known from D3 through the opening between the reflector and surface (43) as can be seen in figure 15. As set out in paragraph [0112] on page 8, the reimaging mirror (62) has a configuration similar to that of "mirror 40 of Fig. 9 and Fig. 9", whereby it appears reasonable to assume, that the second "Fig. 9" should read "Fig. 10" instead.

The rays of light as indicated in figure 15 leave the reimaging mirror (62) in a direction that is "essentially perpendicular" to the first optical axis. The term "essentially perpendicular" is to be interpreted in the light of the definition of dependent claim 7 of the patent in suit as encompassing an angle within the range of 50° to 150°.

5.5 The light source used in D3 is a LED (cf. paragraph [0055]) which is in good approximation a Lambertian source.

5.6 The appellant argues that claim 1 refers to two alternatives: "the concavity occupies a solid angle greater than pi steradians", and "at least 30% of the light rays are intercepted by the reflecting surfaces". Since the reflector of figure 7 fulfils the second criteria, D3 anticipates the subject-matter of claim 1.

5.7 The term "in any case" in claim 1 however cannot be understood as "or". Claim 1 requires that the concavity formed by the two reflecting surfaces must cover more than pi steradians, (mathematical equivalent to "more than a quarter of the solid spherical angle") which must allow reflection of at least 30% of the light rays emitted by the light source. The amount of 30% is not a characteristic of the reflector surfaces as such but the intended result to be achieved.

5.8 Having regard to the above understanding of the wording of claim 1, the subject-matter of claim 1 differs from the optical lighting system using a reflector according to the embodiment of figures 9 and 10 of D3 in that

(a) the concavity defined between first and second reflecting surfaces occupies a solid angle greater than pi steradians, i. e. greater than a quarter of the solid spherical angle; and

(b) at least 30% of the light rays emitted by the light source are intercepted by first and second reflecting surfaces.

5.9 Furthermore, the subject-matter of claim 1 differs from the lighting system using a reflector according to the embodiment of figure 7 of D3 in that

(a) the concavity defined between first and second reflecting surfaces occupies a solid angle greater than pi steradians, i. e. greater than a quarter of the solid spherical angle.

1.2 Neither the embodiment of figure 7 nor the embodiment of figures 9 and 10 hence prejudice novelty of claim 1.

Inventive step (Article 56 EPC)

2. The subject-matter of claim 1 is not obvious when starting from document D3 as closest prior art.

2.1 The subject-matter of claim 1 differs from the embodiment of figure 7 of D3 as set out above in that the concavity defined between first and second reflecting surfaces occupies a solid angle greater than pi steradians, i. e. greater than a quarter of the solid spherical angle.

2.2 There is no indication in the prior art that would suggest to the skilled person to increase the solid angle of pi steradians covered by the reflector of figure 7 of D3.

2.2.1 The appellant argued that for an increase of the portion of reflected light from about 25% to 30% it would be sufficient to enlarge the reflector such that it only covered 6° more. It hence would also cover more than pi steradians, this being only a slight and straightforward modification of the known reflector of figures 9 and 10 of D3.

2.2.2 However, there is no reason why the skilled person would consider such an increase of 6° without having previous knowledge of the invention according to the patent in suit and in particular of the target percentage of 30% to be achieved. It is thus neither obvious to amend the reflector of figure 7 nor of figures 9 and 10 of D3 such that it covers a solid angle of more than pi steradians.

3. The appellant further argued starting from document D4.

3.1 Document D4 claims priority from DE 102006041942 dated 7 September 2006 and was published on 16 April 2008, i. e. D4 was filed before but published after the relevant date of the patent in suit (5 October 2007).

3.2 D4 is hence prior art under Article 54(3) EPC only and cannot be considered when assessing inventive step.

4. Further lines of argument were not presented by the appellant. In particular, novelty and inventive step of independent claim 16 being directed to a lighting device was not questioned by the appellant.

Partial reimbursement of the appeal fee

5. By withdrawing the main request for maintenance of the patent as granted (submitted with the statement of grounds of appeal) and requesting as a new main request (with letter dated 25 March 2021) the maintenance of the patent in the amended form which was allowed by the opposition division and thus the dismissal of the opponent's appeal, the patent proprietor has, in effect, withdrawn its appeal before a decision was issued.

The patent proprietor is thus entitled to a reimbursement at 25% of the appeal fee according to Rule 103(4)(b) EPC.