Ravi Kamal Bali v. Kala Tech & Ors.

Facts

• The plaintiff (Ravi Kamal Bali) held a patent for a tamper-proof closure mechanism for containers
• The defendant (Kala Tech) manufactured and sold containers with a similar closure mechanism
• The plaintiff alleged that the defendant's product infringed his patent by incorporating the essential features described in his patent claims
• The defendant argued that its product worked on a different principle and did not fall within the scope of the patent claims

Issues

1. What methodology should be applied to determine patent infringement
2. Whether the defendant's product falls within the scope of the plaintiff's patent claims
3. What is the role of patent claims in defining the scope of the monopoly

Held

• Identify the essential integers (elements) of each patent claim
• Compare each integer with the corresponding feature of the alleged infringing product
• If all essential integers are present in the accused product, infringement is established
• Variations in non-essential features do not avoid infringement
• The doctrine of equivalents may apply where the accused product achieves substantially the same result in substantially the same way

Ratio Decidendi

Patent infringement is determined by comparing the claims of the patent specification with the alleged infringing product or process. The claims define the metes and bounds of the patentee's monopoly. Each essential element (integer) of the claim must be found in the accused product for literal infringement. Where literal infringement is not established, the doctrine of equivalents may apply if the accused product performs substantially the same function in substantially the same way to achieve substantially the same result.