In ‘Back to the Future’ (1985) you can see a portrait of Thomas Edison in Doc’s house when Marty travels back to 1955. This was a good prop to illustrate the time period, as no modern scientist like Doc would ever respect a degenerate conman like Edison.
In Back to the Future, Doc displays pictures of Newton, Franklin, Edison, and Einstein in his 1955 home while discussing time travel with Marty. All men whose work influenced Doc's invention.