1. The grant of a patent right is a relationship between one person and many people. Once an exclusive right is granted to a patentee, others are deprived of chances of enjoying such the right. And, the subject matter that a patent right wants to protect is a technical thought. To confirm the scope of the invisible body of a technical thought, and to let the public clearly know the exclusive scope of such a patent right, it is necessary to use written words to confirm the protective scope that the inventor wants to claim and to announce the written words to the public. According to Article 106, Paragraph 2 of the Patent Act, the scope of a utility model patent is decided by claims described in the specification. Therefore, claims described in a specification are the scope of a patent right and are also the scope of the right a patentee could assert. However, it is not easy to express technical thoughts by words. And, the core of technical thoughts might arise clearly as the spirit of the technical thoughts, after the patent is published, a slight structural difference results in accused infringement, or the relevant technology in the field becomes mature. Therefore, to take into consideration the insufficiency of words for explaining technical thoughts and to prevent others from easily substitute the content of a patent so as to avoid liabilities for patent infringement, when judging whether a patent was infringed, the doctrine of equivalents becomes a quite important principle. The principle supplements the insufficiency of the literal-infringement principle and is based on the exact value of a patent to assure that fair protection of a patentee and to keep the public´s expectation of social justice. Secondly, technical thoughts express their objective scopes by words so as to then acquire protection as a right. Thus, the primary principle of judging patent infringement is to use literal meanings to explain claims as so to decide whether literal infringement exists. If literal infringement is not established, based on the above-mentioned reasons, the doctrine of equivalents must be used to explain a claim to judge whether an accused infringing product constitutes infringement under the doctrine of equivalents. This Court has original authority to explain the content of a claim. Therefore, although the Patent Act does not have provisions to express that, the court can rely on its own authority to use the exact spirit of each patented technology as a ground to equivalently explain a claim. However, the over application of the doctrine of equivalents also causes the uncertainty of the scope of a claim. Therefore, the key point of judgment is to compare the product element that another person substitutes and the element of the patent at dispute and to see if, in views of a person acquiring general knowledge in the technical field, in terms of evaluation of patented technology, no substantive difference exists, or the function, way and result are substantially the same. If there is no substantial difference, meaning the capability of being substituted, the judgment of infringement under the doctrine of equivalents should be made. And, when judging equivalency, all elements in each claim must be compared with the equivalent elements of an accused infringing product element by element. The comparison is not made in terms of an invention as a whole; otherwise, the comparison of equivalency is misleadingly too broad. That makes no difference where a court is utilized to expand a claim. The trust of the public on the publication of a patent is disobeyed.

2. "Stopping element" of the patent at dispute is only recited in claim 4, while claim 1 only recites "positioning hole" but does not recite "stopping element." Appellant has taken claim 1 as his asserted right. So, it is a violation of the above-mentioned principle that all elements of each claim are compared one by one when the elements of claim 4 and the elements of claim 1 are together compared with the elements of a product at dispute, which is not appropriate in terms of an invention as a whole. And, the associated technical features of claim 4 are "each upper trail has a removable stopping element at the downside of the upper trail, so as to stop the corresponding upper sliding member from leaving from the downside of the upper trail." This is an addition-typed dependent claim, meaning that the stopping element is not recited in claim 1 as a technical feature. So, the upper and lower positioning holes and stopping element have three location-limiting structures. In views of the recited contents in claims 1 and 4, the upper and lower positioning holes and stopping element of the patent at dispute are set in the upper trail. Although there are totally three location-limiting structures, claim 1 of the patent at dispute does not recite a stopping element. So, the stopping element is not an item for comparison. Return to the products at dispute One to Three; the upper trail only has one positioning hole while the stopping element is set in the lower trail; totally there are two location-limiting structures, where only the positioning hole is an item for comparison. Therefore, the original court considered the stopping element of the products at dispute One to Three to be substantially the same with the positioning hole of the patent at dispute, which makes no difference where the element C of the upper trail and the element D of the lower trail are construed to be the same one. And, that also makes the element E of the upper sliding member and the element F of the lower sliding member become one. Even the stopping element of claim 4 was combined with claim 1 for discussions, which leads to the decision of being substantially the same. It was an obvious violation of Article 106, Paragraph 2 of the Patent Act, where the scope claim 1 was inappropriately construed.

Scope of a utility model patent, literal infringement, doctrine of equivalents, infringement under the DOEs.