A highlighter's a form of felt-tip pen which's used to highlight sections of documents in a vivid colour, while leaving the content beneath the marking unobscured. As such, highlighter ink's translucent. History In 1962 the first felt-tip pen was invented in Japan by Yukio Horie. A highlighter's a felt-tip pen filled with transparent fluorescent ink. Although Avery Dennison Corporation invented and trademarked the name Hi-Liter, they didn't invent the felt pen. Styles Many highlighters come in b… (More on Highlighter)