Richard Yong WANG  Partner, Lawyer and Patent Attorney

 

 

An invention relating to formula refer to one that the inventor creates by way of optimizing and adjusting the existing formula or generalizing so as to solve a specific technical problem or meet new application needs in his invention process. This kind of invention improves the accuracy, raises the reliability, or optimizes the calculation process of a formula by adjusting its parameters, optimizing its algorithm, improving its model, or combining and integrating the formula.

 

In the Guidelines for Patent Examination, inventors are allowed to use formula in the application documents, including use of formula to define the scope of protection of the claims, but there are no specific provisions and directions on how to draft inventions relating to formula. And some patent agents have some incorrect concepts and practices in the process of writing application documents for such inventions, resulting in some patent applications being rejected during the prosecution process. Even if some applicants are lucky enough to have their applications patented, such patents would be invalidated due to substantive defects in the application documents in subsequent invalidation proceedings, and the inventions obtained with the inventor’s hard work would not be effectively protected, and their initial investments wasted.

 

The following is an overview of the basic opinions of the Supreme People’s Court (SPC) on treatment of inventions relating to formula, using the invalidation process of a Chinese patent, as well as the considerations that patent attorney should pay attention to when drafting inventions relating to formula.

 

 

Basic Facts of the Case
 

Company A is the patentee of the invention patent No. ZL200710049004.9 entitled “high-efficiency laminated graphite discharge gap device”. On January 21, 2020, Company B requested the China National Intellectual Property Administration (CNIPA) to declare invalid the entire patent involved in the case. On September 2, 2020, the CNIPA made Decision No. 46045 on the examination of the invalidation request, holding the patent valid.
 

On June 28, 2021, the Beijing Intellectual Property Court (BIPC) rendered the (2020) Jing 73 Xingchu No. 15901 Administrative Judgment, rejecting Company B’s appellant claims after the appeal was filed. Company B then appealed to the SPC, and on November 22, 2023, the SPC rendered the (2021) Zui Gao Fa Zhi Xing Zhong No. 1071 Administrative Judgment, revoking the administrative judgment of the BIPC and the CNIPA’s decision on the invalidation request. The CNIPA was required to make a new examination decision on the request for invalidation of the disputed invention patent.

 

Although there are a number of grounds for invalidation in the invalidation stage of CNIPA and the first-instance administrative lawsuit of BIPC, such as whether the description disclosure is sufficient (i.e., Article 26.3 of the Chinese Patent Law), whether the claims are supported by the description (i.e., Article 26.4 of the Chinese Patent Law), and whether claims 1-10 possess inventiveness (i.e., .Article 22.3 of the Chinese Patent Law), the SPC judgment only commented on whether the description disclosure was sufficient. It is concluded that the technical solution of independent claim 1 and its dependent claims is not fully disclosed, and the patent involved in the case does not comply with Article 26.3 of the Chinese Patent Law.

 

For this author, the above-mentioned SPC judgment has grasped the fundamental issues of the patent involved in the case, and has given directions on how to draft formula-related inventions, which is of strong guiding significance for patent practitioners in their drafting and examination for the similar cases in the future. Therefore, this article will be focusing on whether the patent in question complies with Article 26.3 of the Chinese Patent Law, and discussing the SPC judgment and its revelation to the practitioners.
 

Patent at Issue

 

The patent at issue relates to a discharge gap device carrying lightning current, which is mainly used for the first level of lightning protection of the power supply system to protect electronic or power equipment from damage caused by lightning induction.

 

Claim 1, which is the basis of the examination in this case, is:
 

"A high-efficiency stacked graphite discharge gap device comprises a π-shaped connecting capacitor group (1) composed of N + 1 discharge gaps and N capacitors with the same capacitance value, said N≥1, each discharge gap is connected in series, wherein the first discharge gap F1 is connected with the live wire, the last discharge gap FN+1 is grounded, one end of each capacitor in the π-shaped connection capacitance group is connected with the conductive part between the two discharge gaps, and the other end is grounded, characterizing in that:
 

1. The discharge gap is a graphite discharge gap, an insulating annular gasket (9) is placed between the graphite electrodes (6) of the graphite discharge gap, and the graphite discharge gap is assembled in layers;
 

2. The capacitance value of each capacitor in the π-shaped connection capacitor group is selected according to the following formula:

C＝In/2πfVK

In the formula, In is the induced discharge current on the capacitor in the π-shaped connection capacitor group，In＝I/N, wherein:

I is the total current of the π-shaped connection capacitor group;

N is the number of capacitor in the π-shaped connection capacitor group;

f is the lightning wave frequency;

V is the rated voltage on the capacitor in the π-shaped connection capacitor group;

K is the safety factor, K ≥ 1.

 

The parameters K, f, V, and I involved in the capacitance value calculation formula of the above claim are all disclosed and defined similarly in the description. 

 

Opinions in the Invalidation Decision and First-instance Court Ruling

 

In the invalidation decision, the CNIPA concluded that the parameters K, f, V and I involved in the calculation formula of the capacitance value in claims 1-10 of the patent involved in the case were clearly defined in the claims and the description, wherein K was the safety factor, f the lightning wave frequency, V the rated voltage on the capacitor in the π-shaped connection capacitor group, and I the total current of the π-shaped connection capacitor group, wherein K, f, V and I all had a certain value range, and the embodiments of some typical lightning current waveforms were disclosed in the patent description in question, citing several typical lightning current waveforms and different values for the above parameters. Those skilled in the art can also select within a certain range according to the changes of the stacked graphite discharge gap device in practical application, and it is not necessary to limit it to a few particularly accurate values to achieve, and from the perspective of those skilled in the art, the technical solution of the patent in question could be realized, the technical problems of the patent in question solved according to the contents disclosed in the description of the patent in question, and the expected technical effects could be produced. The technical solution claimed by the claims complied with Article 26.3 of the Chinese Patent Law.

 

The court of first instance basically agreed on the opinion of the invalidation decision, holding that the patent description in question had clearly and completely explained the parameters in the π-shaped connection capacitor group, and found that the patent description is in compliance with Article 26.3 of the Chinese Patent Law.

 

Analysis of the SPC Opinions

 

In the description of the patent in question, the formula C=In/2πfVK has five parameters, namely, C (capacitance value), In, f (lightning wave frequency), V (rated voltage on the capacitor in the capacitor group) and K (safety factor), where In=I/N is determined by the total current of the capacitor group I and the number of capacitors in the capacitor group.
 

According to the contents disclosed in the description, this formula is applicable to the calculation of graphite discharge gap capacitance value C for different lightning waveforms, especially to solve the uncertainty problem of its calculation. The technical effect it achieves is: in "according to the capacitance value selection formula provided by the present invention, once the V of the device is determined (a lower limiting voltage can be selected), a relatively small (safe) capacitance discharge current In is selected, and the frequency f is estimated according to the lightning test waveform, the value of each capacitance in the π-shaped connection capacitance group can be calculated, therefore, the operability of the formula is strong, and it is suitable for use under the lightning wave impact shape such as 8/20μs, 10/350μs, 1.2/50μs. That is to say, the gist of the present invention is that the value C of each capacitor can be obtained by using the formula when In, f (lightning wave frequency), V (rated voltage on the capacitor in the capacitor bank) and K (safety factor) are determined.

 

The contents disclosed in the description shows that In, f, and V are related to the specific structure, design parameters and performance indexes of the discharge device, and need to be specified or calculated in advance. Therefore, in a discharge gap device with defined performance indexes and design parameters, the determination of the C value depends only on the other two parameters, namely K (safety factor) and f (lightning frequency).

 

The description does not give any information as to how the formula C=In/2πfVK was obtained, neither the theoretical derivation process nor the experimental basis on which it was obtained. For the value of K, K≥1 is specified in the description.

 

For the field of lightning protection, it is well known that the lightning waveform describes the characteristics of the current or voltage over time during the lightning discharge, while the lightning frequency describes the frequency characteristics of the lightning phenomenon, and the frequency component can be obtained by spectral analysis, usually containing a broadband frequency component, ranging from DC to several hundred megahertz.

 

For the above formula, four embodiments are given in the description of the patent in question, which are summarized as follows:

 

	In	V	K	f	C
The 1st embodiment	2.1/7 A	3000V	2	18X103Hz	440pF
The 2nd embodiment	3.2/8 A	3000V	3	18X103Hz	390pF
The 3rd embodiment	4.5/9 A	3000V	2	18X103Hz	737pF
The 4th embodiment	1.8/6 A	3000V	3	18X103Hz	295pF

 

In the above four embodiments, the lightning wave frequency f is selected as 18X10³Hz .

 

Further, to simplify the discussion of the problem, the author simplifies the above formula as C=afK, wherein a=In/2πV, for any specific discharge gap device, in the case of defined technical indexes and parameter ranges, a is a computational quantity greater than 0, which can be pre-calculated. With the K value fixed, C can be thought of as a linear function of f, and since f cannot be negative, in a Cartesian coordinate system, the formula can be expressed as a ray in the first quadrant from the origin of the coordinates. If the f-value is fixed, the slope of the ray changes as the K-value changes, as shown in the figure below:

 

 

According to the contents disclosed in the patent description in question, f can vary in the range of several hundred to hundreds of megahertz, and K can vary in the range greater than or equal to 1, and the range covered by the above formula in the coordinate system is shown in the shaded part. Obviously, the number of combinations of parameters (K,f) included in the shaded part is extremely large, even infinite. In addition, it should be noted that the above diagram is only a simplification of the diagram assuming that K and f are independent of each other, and if the values of K and f are related, the possible parameter combinations of (K, f) may be located in the region of a polygon or other patterns.

 

Among the four embodiments given in the description of the patent in question, f only gives one examplary value, f = 18X10³Hz, and K gives only two values, K = 2 and K = 3. Even if it is assumed that the four embodiments disclosed in the description are true and correct， and can achieve the technical effect they claim, how can a person skilled in the art be assured that the effect of the present invention can be achieved by an infinite number of possible combinations of f that varies in the range of several hundred to hundreds of megahertz and K that may take anyone of the value greater than or equal to 1 under the premise of satisfying the formula?

 

Since this patent also involved a related infringement litigation in the course of administrative lawsuit, namely the (2020) Zui Gao Fa Zhi Min Zhong No. 329 Case (hereinafter referred to as the infringement case), the SPC demonstrated the issue of whether the invention disclosure of the patent in question was sufficient from two perspectives in its administrative lawsuit decision on the case.

 

First of all, from the positive side, that is, from the perspective of the patent drafting itself, the issue of sufficient disclosure of the invention is analyzed by the SPC.

 

Pursuant to Article 6.1.3 of the SPC Provisions on Several Issues Concerning the Application of Law in the Trial of Administrative Cases Involving the Grant and Confirmation of Patent Rights (I), if the description does not fully disclose the specific technical content, resulting in excessive labor required to confirm that the technical solution defined by the claims can solve the technical problem to be solved by the invention or utility model, the people's court shall determine that the description and the claims related to the specific technical content do not comply with Article 26.3 of the Chinese Patent Law.
 

Specifically, with regard to the patent in question, the SPC held that according to the description of the patent, a person skilled in the art could conveniently and easily calculate the value of capacitance C according to the numerical range of the parameters given by In/2πfVK in the equation. However, when he or she selects the lightning wave frequency f and the safety factor K, he or she cannot know how to select the corresponding value of the lightning wave frequency that varies within the geometric progression range based on technical common sense. If he or she chooses a calculation parameter to determine the value of a limited capacitance from a wide range of values within the above-mentioned range, the interval of the above-mentioned range of values is not a finite, but an infinite range in which the frequency of "K≥1" and "lightning wave frequency" varies according to time and region, and the capacitance value derived is also a value within the infinite range.
 

In the description of the patent in question, when the technical solution limits the selection of the capacitance value of each capacitor in the capacitor group, K≥1 is defined, while K = 2 and 3 are adopted in the embodiments, and no further basis for the selection of the open interval of K is given in the description; at the same time, f is defined as the lightning wave frequency in the description of the patent in question, and f≈18×10³Hz is uniformly adopted in the all four embodiments, and the basis for such selection for different lightning waveforms is not further explained in it.

 

Accordingly, the SPC concluded that Company A did not give a clear explanation in the description, so that a person skilled in the art could not choose the values of the safety factor K and the lightning wave frequency f within a reasonable range without creative or excessive labor. Nor can a person skilled in the art select the specific values of the safety factor K and the lightning wave frequency f through a finite number of experiments, and then determine the capacitance value  through the formula C=In/2πfVK, which may be used in this field as reference.

 

In other words, according to the formula of the present invention, in the nearly infinite possible combinations of (K, f) as shown in the figure above, the description of the patent in question does not give sufficient embodiments or reasons to show that other combinations of (K, f) other than the four embodiments can also achieve the technical effect of the present invention.

 

To further strengthen its preceding conclusions, the SPC also made a detailed analysis and argument for the trial process of the infringement case.

 

In the infringement case, Company A asserted that the choice of capacitance value of the alleged infringing product of Company B was in accordance with the formula C=In/2πfVK of the patent in question, that is, the choice of capacitance value of the allegedly infringing product was the same as that used by the patent in question. To verify whether the capacitance values of the six capacitors of the allegedly infringing product it purchased conformed to the formula in the description, Company A invited an appraisal institute to conduct an appraisal. The average capacitance value of the above six capacitors obtained at the 1kHz test frequency is determined as 1.06nF,that is C=1.06nF, and I adopts a specific current waveform, i.e., 8/20μs30KA and 10/350μs6KA, and measures the current flowing through the wire by "external wire" and an ammeter, and obtains "positive polarity 404A, negative polarity 480A" and "negative polarity 222A" respectively; N is the number of capacitors in the capacitor group, that is, 6; by multiplying the half-peak time in the above-mentioned current waveform, i.e., 20 μs and 350 μs, by 2, the period of the current waveform, i.e., 40 μs and 700 μs, and then the respective lightning wave frequencies f are calculated, i.e., 25 kHz and 1.4 kHz, respectively; V adopts the maximum limit voltage recorded in the allegedly infringing product, which is 2500V. The above parameters are respectively brought into the formula C=In/2 π fVK for calculation, determining K are positive polarity 162, negative polarity 192 and negative polarity 1588 respectively. By bringing the above parameters of another allegedly infringing product into the formula "C=In/2πfVK" for calculation, determining K are the positive polarity 121, the negative polarity 117 (8/20 μs current waveform) and 1040 (10/350 μs), respectively. In short, when appraising the allegedly infringing product, the appraisal institute derived the safety factor Ks used in the allegedly infringing products through the measured capacitance value C and the defined f value and other design parameters of the allegedly infringing product according to the above equation.

 

Based on the above identified facts in the infringement case, the SPC held that with reference to the measured value of C, the values ​​of K calculated according to the formula are positive polarity 162, negative polarity 192, negative polarity 1588, positive polarity 121 and negative polarity 117 (8/20μs current waveform), 1040 (10/350μs) respectively. The calculated result of K differs significantly from the four embodiments described in the involved patent description, in which K is chosen to be equal to 2 or 3. Company A did not explain how to select these values of K for calculating the corresponding capacitance values in the infringement litigation and the administrative lawsuit. In addition, when determining the technical features of the infringing product, Company A did not give a specific basis for the selection of the safety factor K value and the lightning wave frequency f, and only explained that they were empirical formula. But, according to the calculation formula C=In/2πfVK given by the present invention, the selection of parameters f and K has a non-negligible and significant influence on the calculation result of the final capacitance value.

 

Based on the analysis and argument of the above two aspects, the SPC concluded that for those skilled in the art, the method given by the patent in question cannot eliminate the uncertainty of the calculation of the capacitance value. Therefore, the technical means of selecting the capacitance value of each capacitor in the capacitor group defined by claim 1 of the patent in question cannot solve the technical problem raised in the description, and does not achieve the technical effect of determining the numerical value of each capacitor in the capacitor group with strong operability as claimed. The technical solution corresponding to independent claim 1 and its dependent claims in the description of the patent involved in the case is not fully disclosed, and the patent involved in the case does not comply with Article 26.3 of the Patent Law.

 

Things to Keep in Mind When Drafting Formula-related Inventions

 

Based on the SPC above ruling, the following is an overview of how to draft similar inventions using the formula C=In/2πfVK of the patent at issue as an example.

 

For the above formula, the definition of each parameter and variable are given in the description of the patent in question, namely: N is the number of capacitances of the π-shaped connection capacitor group, f is the lightning wave frequency, V is the rated voltage on the capacitor in the π-shaped connection capacitor group, K is the safety factor, and the range of K is given：K ≥ 1.

 

Although the CNIPA Reexamination and Invalidation Board and the BIPC held that the description and the embodiments had fully disclosed the invention in question, the SPC replied in the negative.

 

According to the above SPC ruling, as well as the patent attorneys’ practice, for inventions relating to formula, in order to meet the requirement of sufficient disclosure, this author believes that at least the following three conditions must be met:

 

1) Each parameter and variable involved in the formula should be clearly explained or defined. This is a very basic requirement.

 

2) If the range of variation of parameters, constants or variables impacts the technical effect achieved, the range of variation should be given; The contents or the number of embodiments disclosed in the description should be sufficient to enable a person skilled in the art to obtain its formula through logical deduction or inductive summary from the prior art, and to be confident that the effect of the invention can be achieved by taking any value within the limited range of relevant parameters or variables, without creative labor or excessive experimentation.

 

3) For formula with multiple parameters or variables, the interaction between them should be clarified or revealed.

 

Referring to the simplified formula C=afK above, since f and K are both variables, there is a range of variation for each of them, and it is obvious that their different combinations of values impact the calculation of C value. If f and K are independent of each other, a plurality of embodiments of the combination of (K, f) with different values should be given, which is sufficient to show that any combination of (K, f) in a given range can achieve the effect of the invention. However, if f and K are related to each other, and the range of values of them impacts each other, that is, the value or range of one parameter will impact the value or range of another parameter, then it is required to disclose the way in which they impact each other, or to give directions on how to determine another parameter or variable based on one parameter or variable.

 

Specifically, with regard to the patent in question, it is clear that the drafting of the description only satisfies the first condition, not the second and third. The reason why the second condition is not satisfied is that in practical application, f can vary in the range of several hundred to hundreds of megahertz, and the embodiment only gives a specific lightning wave frequency value of f=18X10³Hz; For the open interval of K≥1, there are an infinite number of possible ranges, and only the embodiments of K of 2 and 3 are given. Therefore, for the specific range of values of f and K, it is obvious that the embodiments disclosed in the patent in question are not sufficient to support the formula summarized by the patent in question. The reason why the third condition is not met is that the description does not disclose whether there is an interaction between the values of f and K, and whether f and K are independent of each other or impact each other.

 

For this author, the basic drafting requirements summarized above are consistent with the SPC opinion in the ruling, that is, "if the claim contains technical features defined by the equation of two or more characteristic variables (i.e., the parameters), , then the relationship between the numerical range selected for the parameters of the equation and the technical effect obtained shall be clearly stated in the description of the invention," and "within the numerical range of the relevant parameters involved in the equation, in principle, all numerical values should be disclosed to the extent that the desired technical effect can be achieved without creative or excessive effort, so that a person skilled in the art can know at the time of implementing the invention whether the numerical value or numerical interval of the parameters determined by the invention has solved the technical problem and achieved the technical effect claimed in the description," and "when determining that the description of the parameters-involved invention sufficient disclosure or not, the more unconventional the method, the more clear and detailed information should be provided in the description." If the parameter information is unclear, so that a person skilled in the art cannot identify the necessary technical means to solve the technical problem in question based on the content of the disclosure as a whole and common technical knowledge, it may be determined that the description does not meet the requirement of sufficient disclosure".

 

If a patent attorney can base on the above-mentioned SPC ruling and the suggestions made in this article on the drafting of inventions relating to formula, carefully analyze the invention, identify the key parameters or variables in the formula, and identify the relationship between the parameters or variables, so that a person skilled in the art can summarize or generalize the formula according to the disclosed content without excessive labor, the patentability and the stability of the  patents or patent application will be greatly increased, and the creative work of the inventors sufficiently protected.

 

 

Author:

 

Mr. Richard Yong Wang

 

Mr. Wang received his bachelor's degree in 1991 from the department of computer science of East China Normal University and his master's degree from the Institute of Computing Technology of the Chinese Academy of Sciences in 1994. In 2005, he received degree of master of laws from Renmin University of China. From 1994 to 2006, Mr. Wang worked with China Patent Agent (HK) Ltd, as a patent attorney and director of Electrical and Electronic Department. Mr. Wang joined Panawell in January 2007.

 

Mr. Wang is a member of the All-China Patent Attorneys Association (ACPAA), Sub-Committee of Electronic and Information Technology of ACPAA, LES China and AIPPI China, and FICPI China.

 

In the past years, Mr. Wang has handled thousands of patent applications for both domestic and foreign clients, and he has extensive experiences in application drafting, responding to office actions, patent reexamination and invalidation proceeding, patent administrative litigation, infringement litigation, software registration and integrated circuit layout design registration. As a very experienced patent attorney and attorney-at-law, Mr. Wang also participated in many patent litigation cases on behalf of a number of multinational companies as leading attorney. Mr. Wang's practices include computer hardware, computer software, communication technology, semiconductor devices and manufacturing process, automatic control, household electrical appliances, and etc.