Patent query

[SAJE]

What is the name of your state (outside U.S.)?

To whom it may concern,

I was wondering how significant a change, or modification, must be made to an existing patented design in order for you to bypass that patent? Case in point, I had a product manufactured in Hong Kong based on another design. I never set out to copy the design only improve upon it, so I used a different more efficient lighting system and constructed it with lighter materials. Last week however, I received a solicitors letter on behalf of the company whose design I referenced, claiming I was infringing upon their patent. Although the outward appearance of my product and theirs are quite similar are the improvements
I made sufficient enough to set the two apart and therefore counteract their patent?

Kind regards,

SAJE.

[seniorjudge]

US law only.