Step 1: Classification of assets.
  
- Current Assets: Cash, stock, debtors, etc. 
  
- Liquid Assets: Readily realizable assets like cash and bank. 
  
- Intangible Assets: Non-physical assets like goodwill, patents, trademarks, copyrights.  
Step 2: Identify patents and copyrights.
  
Patents and copyrights are legal rights, non-physical in nature, and generate future economic benefits. Thus, they are intangible assets.  
Step 3: Conclude.
  
Hence, patents and copyrights are classified as Intangible Assets.  
  
 
Final Answer:  
\[
\boxed{\text{Intangible Assets}}
\]