Because the value of a patent depends not only on the cost of obtaining a patent, but also on the use value of the patent, and in many cases it even depends entirely on its use value, which has little to do with the cost of obtaining a patent, it is decided that the patent evaluation method should be based on the present value method of income, but only in some special cases can the repeated cost method be adopted. The present value of income method is applied to patent evaluation, and the fundamental problem of calculation is how to find, judge, select and calculate various technical indicators and parameters in patent evaluation, that is, the amount of income, discount rate and profit period of patent right. Patent income refers to the expected income directly brought by patent rights. The calculation of income can usually be obtained by directly measuring excess income and measuring profit sharing rate. The key to the value of patent right is that it can obtain excess income. If an application for a patent right can't produce excess income at all, then it probably can't form intangible assets, or it can't be estimated by the present value method of income. The source of excess income lies in the increase of income and the saving of cost. Therefore, we can divide the patent right into increased patent and reduced patent.
Appraisers should calculate their excess returns according to different types. Profit sharing rate is used to calculate the benefits of patented technology, that is, based on the total benefits generated by patented technology investment, the benefits of patented technology are determined according to a certain proportion (profit sharing rate). The profit sharing rate reflects the contribution of patented technology to the whole profit. According to the United Nations Industrial Development Organization's analysis of the price of imported technology in developing countries such as India, it is considered that the profit sharing ratio is reasonable between 16-27%. Our theorists and appraisers think that the profit sharing rate is reasonable between 25-33%. These basic analyses have reference value in the actual business evaluation process, but it is more important to actually analyze the evaluated patented technology and determine a reasonable and accurate profit sharing ratio.