The Patent Examination Guide stipulates clearly the definition and selection of the analogous art, analogous art means a technical solution in the existing technology that is the most pertinent to the claimed invention, which is the basis to determine whether the invention possesses prominent substantive feature. The analogous art, e.g., may be in the same field of endeavor, is targeted at a technical problem or has the technical effect or usage that is the most pertinent, and/or discloses the most elements of the claimed invention; or although it is in a different field of endeavor, but performs the same function and discloses the most elements of the claimed invention. Notably, in considering the most pertinent art, it should first be taken into account of the prior art in the same or a similar technical field. Meanwhile, The Operating Rules of Patent Examination further clarifies that examiners should generally consider and select the analogous art in the following sequence: (1) first consider the prior art in the same or similar technical field; where the technical field is the same or similar, then consider the prior art addressing a technical problem, having the technical effect or usage that is most pertinent to that of the claimed invention, and then consider a prior that discloses the most elements of the claimed invention. (2) In the event that no prior art exists in the same or similar technical field, examiners may consider a prior art in a different technical field, but performs the same function and discloses the most elements of the claimed invention.
I. The Problem
During examination, examiners will usually find a number of references that are pertinent to the subject matter of the invention, or in the invalidation process, a challenger of a particular claim will similarly find significant amount of evidence pertinent to the subject matter of a patent claim. Then, particularly when combination of different prior art or evidence is used to evaluate inventiveness, the selection of analogous arts would become an indispensable step. And when different prior arts are combined as references for inventiveness considerations, opinions have always varied as to whether different selections of analogous arts would lead to different results. Some believe that different selections of analogous arts would not lead to different conclusions on the inventiveness, but would merely make the reasoning process vary in degrees of difficult. Others argue that different selection of analogous arts might lead to totally different conclusions. One article pointed out, "We might as well begin with the simplest scenario. Assume that the claimed invention contains two limitations a and b, and reference A discloses the element a, and reference B discloses the element b. When reference A is used as analogous art, the difference is element b; if the prior art teaches a suggestion to combine element b with reference A, then the invention subject matter is obvious. If there exists such teaching, then the element b in reference B functions the same as in the claimed invention. Conversely, when reference B is selected as analogous art, the difference is element a. It can be inferred without doubt that element a in reference A functions the same as in the claimed invention. That is, there exists a teaching to combine element a with reference B, and the invention is obvious. As it shows, whichever reference is used, the analogous art will lead to the same conclusion." However, this article further notes, "We can push this assumption to an extreme where the comparison document A discloses both the features a and b, while the comparison document B discloses none. If the comparison document A is determined as the CPA, the combination of the two comparison documents will lead to a conclusion that the claimed invention is not inventive. However, what will result, if the comparison document B is selected as the CPA, and the two documents are then used to draw a conclusion?" Here, the article does not go on to analyze whether in this extreme situation, the state of the art in general terms suggests and motives the person skilled in the art to combine the different comparison documents.
The first part of the article indicates that technical suggestion is not directed. When the two comparison documents are combined, although the two documents address different technical problems, the technical suggestion exists as long as the distinctive feature missing in one of the documents exists in the other document, and this missing feature functions in the comparison document in the same way as in the claimed invention. In this situation, the selection of different comparison documents will not lead to different conclusions. However, I cannot agree with this. I argue that technical suggestion should be directed, and the direction is apparent, in particular when the selected analogous art is not in the same technical field (such as, a different or a closely related technical field) as the claimed technical scheme. Now, in view of two real cases from my practice, I will explain how the selection of comparison documents affects the inventive conclusion. I will also introduce my thinking on the importance of the technical field in the analogous art selection.
II. Case Studies
Case 1 relates to a method of manufacturing a display apparatus in the independent claim. Although the title [sic, preamble?] did not specifically limit the type of apparatus, a person skilled in the art (PHOSITA) can determine that the apparatus is a type of field emission display from the manufacturing step including the element of "forming an emission source of oxidized porous silicon on the inner surface of said first substrate." In the Office Action, the Examiner cited two references: reference 1, which was a gas discharge type display involving an MPDP (Mini Plasma Display Panel); and reference 2, which was a field emission type display involving a field emission type electron source. The Examiner used reference 1 as the prior art, which was totally different from the claimed display, and after determining that the difference between the independent claim and reference 1, noted that the difference lay in the technical problem it intended to solve – providing emission source – which was disclosed by reference 2 that functioned the same as the claim in providing an emission source on the first substrate. Therefore, reference 2 serves as a teaching for applying the above element to reference 1. The Examiner added by rejecting applicant's response that "although the display devices disclosed in reference 1 and reference 2 are of different types, they both belong to the field of displays, and both must address the technical problem of emission source." The study of the above case, however, shows that although generally speaking, they belong to the same technical field, reference 1 and reference 2 have different working principles. In reference 1, the display emits light through gas discharge that stimulates the fluorescent powder. It does not need an electron source, and is a gas discharge type display. In reference 2, the display gives out light through the cathode that emits electrons to stimulate the fluorescent powder. It needs an electron emission source, and is a field emission type display. Although reference 2 discloses the feature that "the oxidized porous silicon formed on the inner surface of the first base plate is used as the emission source", as reference 1 is a gas discharge type display that never needs an electron emission source, and never needs to address the technical problem with any emission source, therefore the person skilled in the art will never try to apply the emission source of reference 2 into reference 1, not to mention the material of the emission source in reference 2. That is, there is no any technical suggestion to apply reference 2 with reference 1 in order to obtain the claimed technical scheme.
Case 2: The case is concerned with an issued utility model patent, which is a small-size high-power relay. In its invalidation request, the requestor provided two pieces of evidence to comment on the inventiveness of the claimed utility model. Reference1 disclosed a hinge type magnetic relay, and basically the same functions and features as the claimed utility model, including the iron core, coil, yoke block, lead terminals, moving/fixed contacts, coil axis, upper/ lower shells, and base plate, as well as their inter relations. Reference 2 was applicant's own previous filing, disclosing a coil frame and a framework made of it to be used in relays.
In its grounds for invalidation, the requestor insisted that the comparison document 1 should be selected as the analogous art, considering that compared with reference 2, reference 1 disclosed the more features of the claimed utility model. Reference 1 which was a hinge type magnetic relay, and reference 2 which was a coil frame type relay, belong to closely related technical fields of relay. In addition, the distinctive feature of the claimed utility model, as different from the comparison document 1, was disclosed in reference 2, and directed at the same technical effect in reference 2 as in the claimed utility model. Therefore, as suggested by reference 1, the combination of the two references could absolutely arrive at the claimed subject matter.
After the study, the collegiate bench found that although it disclosed more features that functioned basically in the same way as the claimed utility model, reference 1, which was a hinge type magnetic relay, adopted totally different structural design thinking from the claimed utility model that was limited to a coil frame type relay. There was no technical problem to replace the hinge structure with the coil frame structure. Therefore, reference 1 which disclosed a hinge structure instead of the claimed coil frame structure and a shield-shape insulation structure instead of the claimed flat piece insulation structure was not suggestive enough as to cause a PHOSITA to replace the hinge structure with the coil frame structure, or to replace the shield-shape insulation structure with the flat piece insulation structure.
III. Conclusion
Although the Patent Examination Guide and the Operating Rules of Patent Examination specifies how to select the analogous art, faced with the actual analogous art selection, examiners or invalidation requestors will possibly consider other elements in practice, for instance, how many claimed features a reference has disclosed, often neglecting the important role of the technical field in the selection. Let's come back to the issue whether the technical suggestion is directed or not. Just as a thing can be both absolute and relative, the state of the art should be a whole theoretically, but in the actual inventive assessment, a selection made from it is relative rather than absolute. Thus, the comparison, which is based on the relatively rather than absolutely selected comparison document, is naturally relative. For instance, an inventive assessment is often concluded with "the claimed invention XX is inventive in relation to the comparison document XX and the comparison document XX", or "the claimed invention XX is NOT inventive in relation to the comparison document XX and the comparison document XX." Therefore, the technical suggestion is necessarily directed. It is directed from the analogous art to other prior arts, and cannot be established until any of such other prior arts contains a relevant technical scheme. It cannot even be without this orientation. Therefore, particularly, the technical field plays an essential role in the analogous art priority selection, because this orientation will be very weak or none if the selected analogous art, though disclosing many of the claimed features, is from a technical field that is different or far away from that of the claimed invention. It is for this reason that the analogous art selection should prioritize prior arts from the same or a similar technical field as the claimed invention. As a matter of fact, in the above two cases, the technical direction would have become more evident, if another reference had been selected as the analogous art.
(Translated by Ren Qingtao)
