4. In patent infringement litigation, the defendant should pay attention to the principle of "reversal of the burden of proof" when collecting evidence. Article 4, paragraph 1, of "Several Provisions of the Supreme People's Court on Evidence in Civil Litigation" stipulates that patent infringement litigation arising from invention patents for new product manufacturing methods , the unit or individual that manufactures the same product shall bear the burden of proof that the manufacturing method of the product is different from the patented method. The law specifically provides for the inversion of the burden of proof in such cases based on the parties' proximity to the evidence and the difficulty of obtaining the evidence. 5. Pre-litigation evidence preservation of intellectual property rights "Several Provisions on Legal Issues Concerning Cessation of Patent Rights Infringement Before Litigation", "Interpretation on Legal Issues Concerning Cessation of Pre-litigation Infringement of the Exclusive Rights of Registered Trademarks and Preservation of Evidence" and "On the Trial Interpretation of Several Issues Applicable to Laws in Copyright Civil Dispute Cases" stipulates that in patent, trademark, and copyright infringement cases, you can apply for pre-litigation evidence preservation. It can be seen that applications for pre-litigation evidence preservation are common in intellectual property infringement cases. After the preservation is implemented, the parties or interested parties shall file a lawsuit within the statutory time period. If no lawsuit is filed in court, such preservation measures should be lifted, or relevant evidence destroyed or returned, and the applicant will also be liable for compensation for the losses caused. In the process of pre-litigation evidence preservation, especially in cases of computer software infringement disputes, when preserving evidence from a computer, attention should be paid to the following: (1) When preserving evidence from a computer, the court should first ask the respondent to understand the information connected to the computer. The number of out-of-home network cables and other computers in the local area network can be cut off from the computer and other computers or stopped at the same time to prevent remote control and modification of the computer. (2) When preserving evidence, it is best for both parties to be present and the judge to perform the preservation operation or if there are no objections from both parties. (3) The evidence to be preserved shall be stored on court equipment or on equipment provided by the parties that has been inspected by both parties and has no content. (4) The preserved evidence carrier shall be sealed by the judge on the spot. (5) Record the entire above process in the transcript, signed by both parties. (6) If possible, it is best to videotape the entire process at the same time. ------Shenyang Intellectual Property Lawyer