A trademark logo is a graphic symbol or design usually combined with type. It is a "mark" used to identify a brand of product or service.
Marketing
The "RR" of Rolls-Royce, the "three stripes" of Addidas, or the script text of Coca-Cola are logos - as are Mr. Clean, Playboy Bunny, Michelin Man, Mickey Mouse and the Gerber Baby.
A well designed logo is an important marketing tool for inventors. It can effectively distinguish an invention from similar products or brands in the marketplace.
It can give immediate recognition for a product, or communicate a desirable impression that will allow a company to have a competitive advantage.
Licensing
A trademark logo is also a tool that helps to license an invention. It can become more valuable, or as valuable, as a successful invention because of collateral licensing opportunities.
An inventor in San Diego invented durable surfing shorts. He designed a logo for his shorts, which was two footprints with ten circular toes and the name "Hang Ten". Today, it is licensed to manufacturers around the world for practically anything to do with surfing - earning millions in revenues.
Many companies, such as Gucci, Walt Disney and Starbucks, license their "marks" for use on other merchandise.
Trademark rights do not expire so long as the mark continues to be used. This is an effective strategy in extending the monopoly of an invention. Wham-O's flying disc trademark known as "Frisbee" is an example of the effectiveness of a trademark after a patent has expired.
Having a good trademark can help license your invention. It is an additional tool that can be included in a business plan as part of a marketing strategy. Trademarks are also relatively inexpensive to register, although you own the rights to your own design whether it is registered or not.