8.5.2 Infringement analysis
8.5.2.1 Comparison of the patented invention with the infringing product or process
A defendant’s product or process infringes the patent only if it falls within the protected scope of the patent. In practice, the plaintiff breaks down the disputed claim into elements and compares them with the corresponding elements of the defendant’s product or process. The defendant provides their answer on whether the elements are appropriately identified and compared, and the court subsequently intervenes to ensure that both parties have the same understanding of the matter. A one-to-one comparison chart is often produced to compare the elements. The elements must be as confirmed in the claim construction process.
For the defendant’s product or process to fall within the scope of protection of the patented invention, every element stated in the claims, and their organic combination, must be included in the defendant’s product or process. If any of the elements is missing, the defendant’s product or process does not fall under the protected scope of the patented invention (all elements rule).
8.5.2.2 Literal infringement
Literal infringement is the most basic type of infringement. It is established when all of the elements and the way the elements are organically combined (as specified by a literal interpretation of the claims) are found in the defendant’s product or process.
8.5.2.3 Infringement by equivalence
Infringement by equivalence is established when the elements of the defendant’s product or process are not literally identical but are equivalent to the corresponding elements of the patented invention.
Infringement by equivalence has positive and negative requirements. In terms of positive requirements, (i) both inventions must have adopted the same principle to solve the problem (identity of solution principles); (ii) in spite of any replacement, the defendant’s product or process must have a substantially identical effect as the patented invention (substantial identity of effects); and (iii) the replacement must be self-evident to the extent that any person of ordinary skill in the art would have easily conceived of it (easiness of replacement). In terms of negative requirements, (iv) the defendant’s product or process must not be a free-to-practice technology that is in the public domain; and (v) the replaced element in the defendant’s product or process must not have been purposefully excluded from the scope of claims in the prosecution process. The patentee has the burden of proof as to the positive requirements, whereas the infringer has the burden of proof as to the negative requirements.
To determine whether the patented invention and the defendant’s product or process use the same principle to solve the problem, the superficial deduction of features recited in the claims does not suffice. Instead, the essence of the technical idea underlying the solution that is unique to the patented invention, in comparison with prior arts, should be identified in reference to the detailed description of the invention along with known technologies at the time of filing and be put under substantive review.84
8.5.2.4 Indirect infringement
In addition to direct infringement, the Patent Act regulates certain indirect acts as constructively constituting infringement. Under Article 127(1) and (2), the manufacturing, assigning, leasing, importing or offering to assign or lease a product exclusively used for manufacturing a patented product or for practicing a patented process, if done so for business purposes, are also deemed infringement.85 The purpose of this provision is to deem acts that are yet to reach the stage of practicing all elements of the patented invention as constituting infringement under certain circumstances if it is highly plausible that such acts would lead to the practice of all elements of the patented invention. The provision thereby offers effective relief against foreseeable future infringement.86
The patentee has the burden of proof. To prove indirect infringement, the patentee must show that the alleged good is used in practicing the patented invention (the use requirement), that the alleged good is exclusively used in practicing the patented invention (the exclusivity requirement) and that the alleged good is made for business purposes.