In its ruling of 13 November 2025 (X ZR 143/23 – Pulsed Laser Radiation), the German Federal Court of Justice (BGH) clarified the requirements for the permissible generalisation of patent claims. The decision makes it clear that technical features presented as a unit in the original disclosure may not simply be separated in the patent claim.

The case and the decision in detail:

The patent in dispute concerns a device for treating the cornea using laser radiation, for example to correct refractive errors. The core of the dispute was the question of impermissible extension.

1. The technical problem: Laser treatment produces plasma bubbles, which can combine to form larger ‘macro bubbles’ within about five seconds. These macro bubbles can deform the tissue and impair the quality of subsequent cuts.
2. The original solution (K9): A solution to prevent this is described in the original documents (the parent application): the laser generates a spiral from the outside to the inside in the posterior section and then immediately afterwards a spiral from the inside to the outside in the anterior section. This ensures that the central, optically critical areas of both cuts are completed within the critical 5-second window.
3. The legal problem: In the granted version, the patent holder had only claimed the posterior cut from the outside to the inside. The BGH ruled that this constituted an inadmissible generalisation. Since the original disclosure presented both spiral movements as inseparably linked to achieving the technical success (avoidance of macro bubbles), the claim could not be reduced to a single feature.
4. The rescue in the auxiliary request: The patent could only be upheld in a version that combined both features – the posterior spiral inwards and the subsequent anterior spiral outwards.

💡 Practical tips for patent strategy:

• Avoidance of ‘isolated features’: When describing a technical solution consisting of a combination of steps, you should present these steps not only as a package in the application, but also (if technically reasonable) explicitly as independently advantageous individual features.

🔍 Focus: The configuration requirement for device claims

Another particularly practical aspect of the decision concerns the question of when a device actually ‘realises’ a patented feature if it is controlled by software.

• Not merely ‘theoretical’ suitability: The BGH clarified that for a device claim, it is not sufficient for a device to be merely objectively suitable for performing a function. In particular, it is not sufficient that the device might only be enabled to perform the functions according to the patent by subsequently installing software or other configuration measures.
• Readiness to perform functions: The device must already be configured accordingly at the relevant point in time. This means that it must already comprise the appropriate software or other means that enable the functions to be performed immediately in the corresponding operating situation.
• Distinction from the prior art: This strict interpretation also serves the purpose of novelty examination. A device from the prior art does not anticipate the invention solely because it would be capable of producing the cut surface as claimed with a corresponding (but not disclosed) control.
• Complexity of programming: The BGH emphasises that different scan patterns (e.g. a spiral from the outside to the inside vs. from the inside to the outside) each require separate programming. Specific data sets must be provided in order to precisely coordinate parameters such as the strength of the laser radiation, distances between interaction zones and speed. Therefore, it cannot be assumed that a configuration for one pattern can be readily transferred to another.

💡 Practical tips for patent strategy:

1. Document the complete configuration: Ensure that the patent application describes that the device is already programmed or configured ‘out of the box’ to perform the specific steps.

2. Data sets as an inventive feature: If the invention is based on complex control, it may be advisable to explicitly claim the provision of specific data sets (as in auxiliary request 4 of the proceedings).
3. Caution with ‘universal devices’: The mere fact that a competing product uses the same hardware and could theoretically perform the patented method does not constitute patent infringement of the device claim as long as the specific configuration is missing.

Conclusion: The decision once again underscores the common practice that technical features which appear in isolation in the claim but as a ‘team’ in the description constitute an inadmissible extension. In addition, the BGH clarified when a device actually ‘embodies’ a patented feature if it is controlled by software.