Introductory Example
An invention describes the problem of thin-walled plastic cups for hot drinks, which can be uncomfortable to hold and may have sharp edges. The aim is to develop a low-cost, lightweight disposable cup that, despite its low material thickness, fits securely in the hand and protects the user from heat.
The invention provides a thin-walled cup with an insulating sleeve that is placed around the grip surface. It protects the fingers from heat, can be made of various materials, can be reused or disposed of, and makes the cup more attractive. In addition, a reinforced rim and special base ensure stability.
A patent application has been filed, and the patent claims are as follows:
- Container (12) for hot liquids, comprising a circular base (14), a thin wall (18) with a circular rim (15) at an open end 5 of the container, and a grip surface that is thermally insulated from the wall (18).
- Container according to claim 1, wherein the handle surface is formed by a surface of a sleeve (13) made of heat-insulating material, which is attached around the outer surface of the wall (18).
- Sleeve (13) made of heat-insulating material for a container for hot liquids, wherein the sleeve has a wall thickness of at least 2 mm and a height of at least 3 cm.
Various objects are publicly known from the prior art, e.g., a commercially available pan.
A broad patent claim with few features is naturally advantageous for the owner, as it provides a very wide scope of protection. The patent owner therefore has to prove fewer features in the case of a potential infringing product in order to show that its manufacturer is using the protected features and to be able to take action against that manufacturer.
However, abstraction, i.e., the omission or generalization of features, does not only have advantages. A patent must fulfill another essential requirement in order to be protectable: it must be new. This means that there must be no object published before the filing date that has already anticipated the patent. Of course, every applicant tries to “inflate” their patent claim as much as possible in order to achieve the widest possible scope of protection. However, if the patent claim already contains known technology (state of the art), this causes the “balloon” to burst.
An example illustrates this with the claimed container. If the patent claim were so broad that it simply covered all containers, the scope of protection would be maximum, but it would not be new. For example, the patent claim could then read “1. Container.” Containers in a wide variety of shapes have long existed, so such a claim would not be eligible for protection due to lack of novelty. The patent office would have to reject such a patent claim, and any patent granted would be declared invalid.
It is therefore crucial to find the right selection and balance of features to ensure novelty. A patent claim that contains too many features of the manufactured product is not useful, but a patent claim that is too general and claims everything will not be recognized as novel either.
Based on this general picture, we can look at a concrete example, namely the coffee mug. What is striking here is that the patent claim was formulated so broadly that its scope of protection even includes pans. At first glance, this seems advantageous, as it covers more products and the protection appears to gain in value. However, such a broad wording is not sufficient to guarantee novelty. It therefore makes sense to include additional features such as those in the second claim, according to which the grip surface is formed by a sleeve made of heat-insulating material. This reduces the scope of protection to the actual invention – protection against scalding provided by the sleeve.
State of the art
And this informal approach, which was previously considered using examples, can now be placed within a legal framework by referring to the law. The decisive factor here is the term “state of the art.” According to the legal definition, this encompasses all knowledge that was accessible to the public on the day before the filing date of a patent—whether through written publication, oral description, use, or other disclosure. Everything that is already known is therefore part of the state of the art and cannot be patented again.
Suppose a pan with certain characteristics was already sold in 1950. Regardless of whether this was documented in books, described in patents, or simply became public knowledge through sales, this pan is considered to be known. If someone submits a patent application in 2025 claiming exactly this pan, it lacks novelty. The claim would fail due to prior art, as the claimed object had already been available to the public decades earlier. The decisive factor is therefore not whether the knowledge is still present or whether it is in general use, but solely whether it was made publicly available at some point before the filing date.
Structurally speaking, prior art is a body of technical knowledge that is defined on a specific date. New knowledge is added every day, and at least in theory, nothing disappears from it.
In 1950, a simple metal cup with a handle was sold publicly. In 1980, a disposable plastic cup without a handle but with thin walls was described in a trade journal. Therefore, the prior art after 1950 already includes the object “metal cup with handle.” The state of the art after 1980 additionally includes the object “plastic cup with thin walls.” Every subsequent filing date must be measured against this updated body of already known knowledge.
This distinguishes the state of the art in patent law from the term you may be familiar with from the fields of product safety or environmental law. The purpose in patent law is different: here, the aim is to reward innovation. The state of the art represents what is known and old. In product safety, on the other hand, the definition of the state of the art serves to ensure a minimum level of reliability. Here, the state of the art is the current standard that must be complied with in order to avoid liability.
An example illustrates the difference: In the 1960s, a thin-walled plastic cup without a heat-resistant coating was launched on the market. Even then, there was a risk that it would deform when used with very hot drinks or even release harmful substances. Today, such cups are considered unsafe and have long since fallen out of use. However, this is irrelevant for patent law. The cup remains part of the prior art because it was once publicly available. Even if it is now uncommon or even banned, its former existence can render a later patent application for a similar cup non-novel.
The examination of novelty requires that no single item in the prior art has all the features of the patent claim. If there is even one complete example in the prior art, the claim is considered not to be novel. Structurally, this procedure is similar to the infringement examination: in both cases, the patent claim is compared with a reference object. In the case of novelty, the reference object is an already known object from the prior art, while in the case of infringement, it is a supposedly copied or used object. In both cases, the comparison of features determines whether the patent claim is fulfilled.
A look at the pan shows how the novelty test works. Patent claim 1 requires a container for hot liquids with a circular bottom, thin walls, a circular rim, and a heat-insulated handle. A commercially available pan fulfills all these features: it is a container, can hold liquids, has a circular bottom and rim, has a wall, and has a handle that is regularly heat-insulated. This means that the prior art includes an object that fulfills the entire claim 1. Claim 1 is therefore not new.
This also shows the parallel to the infringement test: if the pan were not already known, but rather an object manufactured subsequently, it would fulfill all the features of the claim and thus infringe the scope of protection. The only difference, therefore, is whether the object of comparison comes from the prior art or from current use.
Novelty in the technology map
Patent claims can be easily visualized with the help of a so-called technology map. The scope of protection of a patent claim is represented as a set. Dependent claims appear in this representation as subsets, since they adopt all the features of the independent claim and add additional features. If two independent claims partially cover the same technical field, their sets may overlap.
Patent claim 1 defines a first set. It covers all containers with a circular base, thin wall, circular rim, and a heat-insulated grip surface.
Patent claim 2 represents a subset of patent claim 1. It additionally requires that the grip surface be formed by a sleeve made of heat-insulating material that is placed around the wall of the container.
Patent claim 3 is a subordinate claim that claims the sleeve as an independent object with specific dimensions. Since it is entirely possible to develop an object that fulfills both patent claim 2 and patent claim 3, patent claim 3 overlaps with the other patent claims.
Specific objects—whether known objects from the prior art or possible infringing objects—can be entered as points on such a map. If a point lies within the set, the object fulfills all the features of the patent claim. If it lies outside, at least one feature is missing. This makes it clear whether an object falls within the scope of protection of a claim or whether a claim is already anticipated by the prior art.
If we transfer the example of the cup to a technology map, the following picture emerges:
The pan falls within the scope of patent claim 1 because it fulfills all the features of this claim. Since the pan does not fulfill the additional feature of patent claim 2, it falls outside the scope of claim 2. It also falls outside the scope of patent claim 3 because it does not have a sleeve.
However, the cup with sleeve described falls under patent claims 1, 2, and 3.
The visualization therefore shows that the pan is only included in the scope of claim 1, while the cup is covered by claims 1, 2, and 3.
Formulation of a request for protection
Before filing a patent application, the question of how to formulate a claim regularly arises. The applicant is usually not familiar with the state of the art in detail and therefore cannot know with certainty which claim version is actually new. So how should they determine what they are entitled to claim if parts of the invention may already be known? The answer is that the applicant does not need to know this in advance. Instead, they can formulate various protection requests side by side, ranging from the more general to the more specific. This is precisely where the applicant can use dependent patent claims to their advantage: the purpose of formulating dependent patent claims is to secure the scope of protection of an invention in a graduated manner. An independent claim formulates the core of the invention in as broad a form as possible. Dependent claims add additional features to this core. They serve as fallback positions in case the broad claim cannot be upheld due to lack of novelty or inventive step. This tiered structure allows the applicant to ensure that at least part of the invention remains protected even if the main claim is rejected.
In this specific case, claim 1 secures the general container with a heat-insulated grip surface. Claim 2 restricts this to the design with a cuff. Further dependent claims could include additional features that meaningfully specify the invention, thereby creating a balance between scope of protection and stability. Conceivable examples include:
A claim that describes the specific material that is both non-slip and heat-insulating.
A claim that specifies that the sleeve is removable and can be used multiple times.
This multitude of claims creates a tiered claim structure: a broad independent patent claim that protects the basic idea and several dependent claims that narrow the scope of the property right and thus protect it against possible objections from the prior art.
The patent office procedure for examining novelty can be explained using the image of a target. Each patent claim represents its own target, which is located on the technology map. The prior art is shot like an arrow at these targets. If the arrow hits the target, this means that the patent claim in question is not new and therefore cannot be protected. If, on the other hand, the arrow misses the target, the claim is secure against the prior art and remains valid.
Applied to the example, this means that claim 1 is a large target because it is broadly defined. The pan or teapot as prior art act like arrows that hit this target precisely – and thus invalidate claim 1. Claim 2 is a smaller target because it is more narrowly formulated. An arrow in the form of the known pan no longer hits this target because the cuff is missing. Thus, claim 2 remains valid even if claim 1 fails. Claim 3, on the other hand, represents a separate target that stands independently alongside the others. Here, the prior art would have to show a cuff with the required dimensions in order to meet the claim.
Defense of the patent in the application procedure
If the patent office is confronted with the application and encounters prior art in the examination procedure that discloses all the features of a submitted patent claim, this claim will be rejected. The office informs the applicant that the patent claim in its current form cannot be upheld due to lack of novelty and requests the applicant to comment or remedy the deficiencies.
In the example of the cup, the patent office would determine in the examination procedure that claim 1 is already completely anticipated by the prior art, such as a commercially available pan. This claim would be rejected and could not remain in this form.
The applicant then has the opportunity to present arguments to convince the examiner that the prior art found does not really fall under the patent claim. In doing so, it may happen that the examiner misunderstands the limits of the patent claim or misinterprets the prior art. In such cases, the application procedure offers the opportunity to convince the examiner that they have drawn the line incorrectly or that certain features are not present in the prior art, as in the pan. These lines of argument can be pursued in an application procedure.
For example, the applicant could argue that the pan cited by the examiner does not have thermal insulation or that there are similar technical differences. The applicant can then discuss these features with the examiner and clarify whether the object found, such as the pan, actually falls within the scope of protection of the patent claim or not.
However, the applicant also has the option of amending the claim, for example by adding additional features or by resorting to dependent claims. In this way, the provisional patent claim (the protection request) can be adapted to the legal requirements or the state of the art, and the remaining core of the invention can be secured.
The applicant could now fall back on claim 2, in which the heat-insulated grip surface is specified as a sleeve. Since pans do not have such a feature, this narrower claim would remain valid and could serve as a protectable fallback position.
In practice, it can be surprising to see what prior art the examiner comes up with during the course of the proceedings. If you do not have any prepared dependent patent claims, you often have to laboriously search the description for differences from the prior art. However, it is also possible to take features from the description and use them to limit the patent claim.
In this specific example, this means that it is not mandatory to choose only the limitation from the original patent claim 2. It is also possible to include a feature from the description and thereby limit the claim. For example, it could be added that the sleeve is made of a specific material, such as recycled cardboard. A new claim formulated in this way would differ from pans or teapots in the prior art, as these do not have a sleeve made of such a material. However, here too, the new claim can only be valid if the added feature is itself new and inventive.
Changes in the application procedure
A significant problem in the examination procedure can arise if a decisive feature is not included in the original application or is not included in sufficient detail. In order to include a feature in the patent claim at a later date, it must have been disclosed in the application on the filing date. The reason for this is that the filing date is determined when the application is filed, which determines the cut-off date for the relevant prior art. If it were permissible to add new technical features retrospectively, the applicant could gain unfair advantages – for example, by incorporating knowledge gained later or even developments by third parties. To prevent this, the principle applies that only what was already fully disclosed in the original document on the filing date can be protected. Subsequent additions are not permitted and will result in the patent office rejecting the amended application.
Suppose that the original application for the cup with a sleeve described cardboard as the material for the sleeve. This material works in principle, but has the disadvantage that, although it insulates hot drinks, it offers little grip and slips easily. Later, it turns out that a special foam not only insulates better, but also provides significantly better grip.
Since cardboard is already mentioned in the original application, this feature could easily be included in a patent claim in order to limit the claim in the examination procedure. The foam, on the other hand, was not mentioned in the original application. Therefore, it cannot be added to the patent claims retrospectively, even if it would be technically advantageous. The consequence: the applicant is limited to the material described in the original application, while later discoveries must be disregarded.
Even more seriously, an inadmissible amendment is not remedied by the granting of the patent. Any third party can take this up and challenge and invalidate the patent on this ground alone. The European Patent Office in particular is very strict in this regard and revokes a patent even in the case of minor changes in meaning. This means that a patent can be declared invalid even in the case of minor formal changes.
If an attempt is made to subsequently include the material foam in the claims, there are two possible consequences. In the application process, the examiner will generally not accept such a change because it was not included in the original application. If the change nevertheless goes unnoticed in a granted patent, the risk remains: any third party could challenge the patent in subsequent nullity proceedings. Since the new feature was introduced inadmissibly, the patent would be invalid. Even the attempt to include foam material retrospectively can thus nullify the entire protective effect.
In many cases, it is therefore only possible to include what was already written verbatim in the application. This is one of the reasons why patent applications are often very detailed and comprehensive. It is impossible to know in advance which feature may later prove decisive for the patent claim, and no one wants to risk forgetting a feature that could prove useful later on.
Patent claims in nullity proceedings
Even if a patent has been granted, it is not unassailable. If, after the patent has been granted, prior art becomes known that the patent office did not take into account in the examination procedure, the patent can be challenged retrospectively and declared invalid. This is done in special proceedings, which are referred to as opposition or nullity proceedings, depending on the stage and legal system. Both give a third party the opportunity to question the protectability of the patent and have it revoked.
The decisive factor is that there is always a third party who wants to remove the patent, usually because they want to use the invention themselves. As a rule, this third party has conducted research and presented relevant prior art. The main reason for the challenge is then usually the lack of novelty.
In the example with the cup patent, let us assume that the examiner overlooked the known pan and the patent was granted in its original form. A competitor who later wants to bring their own pans to market discovers this prior art and files an opposition against the patent. Since the pan has all the features of the granted patent claim, the patent is assessed as not novel in the proceedings and declared invalid. The result: the scope of protection of the patent is lost, as if it had never existed.
The opposition or request for revocation can also be filed on the basis of a search by the patent office, arguing that the office has incorrectly assessed the novelty. It is possible that the prior art was misinterpreted or that the office did not correctly understand the features of the patent claim that it found.
Applied to the cup patent, the case could be as follows: The examiner found an old document with a pan, but did not classify it as prejudicial to novelty. His reasoning: he did not consider the wall of the pan to be “thin” within the meaning of the patent claim. However, a subsequent opponent could argue that the wall thickness should indeed be considered thin and that this feature is therefore also fulfilled. With this different interpretation of the feature “thin wall,” the prior art would cover all features and the opposition could be successful.
In opposition or nullity proceedings, the patent holder also has the opportunity to respond to the objections. They can either insist on their previous patent claims and attempt to defend them, or they can submit one or more proposed amendments. These may, for example, be a limitation of the claims by means of additional features. The court or the competent authority then decides on the proposed versions. In this way, the patent holder can at least save the patent in a limited form, even if the originally granted claim does not remain valid.
In opposition proceedings, a third party argues that a teapot with a thin wall is already state of the art. This would mean that claim 1 is no longer novel. The patent holder could now insist and argue that the pan does not have a thin wall within the meaning of the claim. If the court or authority does not share this view, the owner could alternatively submit an amended claim. For example, they could take the cuff from the dependent claim and claim: “Container according to claim 1, wherein the grip surface is formed by a cuff made of heat-insulating material.” Then the pan from the prior art would no longer meet the claim because it does not have a cuff. The authority will decide in further proceedings whether to accept the original or the limited claim. In this way, the patent can remain in force, albeit in a reduced form.
