The Taiwan Patent Act excludes the outer appearance of a design from being granted a design patent if it is dictated by its function only. The so-called pure functionality refers to features of an article that exist solely to serve the function or structure of the article itself or another article. Examples include the threads of screws and nuts, the grooves and serrations of lock holes and keys, etc., where the outer appearance is dictated purely by functional considerations or is required to connect or assemble with another article to fulfill their respective functions and achieve their intended purpose. Since a design patent is granted to the essential shapes of the must-fit parts between two articles, such purely functional outer appearances are not eligible for design patent protection.
A patent design generally combines a product and its design, while products often possess functionality. Therefore, understanding what kind of outer appearance would be regarded as purely functional, thereby indirectly affecting the eligibility for obtaining a design patent, is of consequence to relevant industries. However, the patent examination guidelines do not explicitly disclose specific principles for such determinations. Some court cases, involving disputes over design patent validity or comparisons of similarity between a design patent and an allegedly infringing product, have provided opinions on the determination of so-called purely functional designs.
Below is a discussion of a recent civil infringement case based on an allegedly infringed design patent, which reflects the court's view on whether an outer appearance of a design is purely functional.
The disputed design patent pertains to a "bra" composed of a silicone elongate body that rises symmetrically from the center toward both sides. The body is symmetrical, with concave arcs located at the top and bottom of its center. These arcs smoothly connect at their ends to become elegant curved lines extending toward both sides of the body. On both sides of the body, three sequentially deformed semi-arcs are arranged in a recessed pattern from top to bottom, seamlessly extending into the edge via smooth curves to form the border. The ends of this border integrate with the curved lines extending from the arcs at the top and bottom of the center of the body, creating a one-piece structure (refer to the patent specification under [Creative Ornamental Features]).
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On the other hand, the allegedly infringing product is a "one-piece silicone invisible bra (NUBRA)," featuring a body that rises upward from the center to both sides before curving downward. The body is symmetrical, with a transparent film extending outward from its outer edge. At the top center of the body, there is a concave arc, with the ends of the arc extending toward both sides of the body in a curved line. On both sides of the body, three sequentially deformed semi-arcs are arranged in a recessed pattern from top to bottom, seamlessly extending into the edge via smooth curves to form the border. The ends of the border integrate with the curved lines extending from the top center arc and the ends of the straight line at the bottom, creating a one-piece structure.
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The court held that the common features shared by the disputed design patent and the allegedly infringing product include: 1) "a silicone elongate body that rises upward from the center toward both sides," 2) "a symmetrical body," 3) "a concave arc at the top center, with the ends of the arc connected to both sides of the body by curved lines," and 4) "three consecutively deformed semi-arc shapes arranged in a recessed pattern from top to bottom on both sides of the body, seamlessly extending into the edge via smooth curves to form the border." These common ornamental features are considered "elements or characteristics that are easily noticeable to lay consumers" and are likely to influence their overall visual impression. After a comprehensive assessment of the impact of these features on the overall visual impression, the court held that the overall appearance of the allegedly infringing product is similar to that of the disputed design patent.
The defendant argued that the disputed design patent is purely functional, since a symmetrical design is essential and cannot serve as a key ornamental element or feature of a bra. Furthermore, the symmetry of the bra, with concave features at the top and bottom of the center, constitutes a purely functional design. The three curved lines resembling waves in the disputed design patent lack any creativity in design, and the upwardly curved ends are purely functional designs well known to the public.
In response, the court held that if the outer appearance of a design patent possesses both functional and ornamental features, and if it creates a certain visual effect, such features are not purely functional and should be included in a comparison between the two designs. Upon a review, the disputed design patent for a "bra" not only provides functionality for women to wear but also allows the creation of various appearances through symmetrical forms involving "shape, pattern, color, or their combinations," which can vary according to different design concepts. This leeway for design is proved by the prior art references cited in the publication of the disputed patent, all of which exhibit different ornamental features and have been granted design patents, including the disputed design patent. This demonstrates that the outer appearance of a bra is not solely dictated by the basic shapes of necessarily matching components. Thus, the ornamental features of the disputed design patent are not purely functional.
The court further found that the defendant did not present any prior art to substantiate its claim. The ornamental features of the disputed design patent, including "left-right symmetry," "concave arcs at the top and bottom of the center," and "three curved lines on each side," allow for creative variations in appearance through modifications and combinations of curved lines and arrangements. These features are not solely determined by functional considerations resulting in necessary basic shapes.
Additionally, the distinctive features of the disputed design patent as illustrated in the drawings, particularly the outer appearance of "three sequentially deformed semi-arcs arranged in a recessed pattern on both sides of the body from top to bottom," is significantly different from the prior art cited in the reference documents and produce a unique visual effect. Its overall appearance exhibits a symmetrical relationship between left and right, with visual design arrangements utilizing the concave and convex changes of curved lines to create an aesthetic appeal. These characteristics establish that the design is not purely functional. Therefore, the defendant's arguments are without merit.
From the reasoning in the court's judgment, it is clear that if the outer appearance of a design, in addition to its functionality, also possesses decorative characteristics that contribute to a certain visual effect, it is not considered purely functional. In the above-discussed case, the disputed design patent for a "bra," aside from serving its functional purpose for women's wear, includes ornamental features such as "left-right symmetry," "concave arcs at the top and bottom of the center," and "three curved lines on each side." These features can be freely created according to different design concepts, and aesthetic appeal, and are therefore not purely functional shapes.
Typically, products are designed to meet their intended purpose and fit their use scenarios, often requiring matching components at corresponding or connecting parts. The challenge for designers lies in how to create designs within these basic shapes that incorporate aesthetic and decorative features to produce distinct visual effects, thereby avoiding purely functional forms. This aspect deserves careful considerations during the designing process.