Lewis Howard Latimer

Longer-lasting lamp filaments. Early carbon filaments burned out quickly. Latimer, a self-taught draughtsman working for Hiram Maxim's lighting company, patented a better way of making carbon filaments in 1882, wrapping them in cardboard while they were baked so they did not crack. Cheaper, longer-lived bulbs followed. He later joined Edison's legal team as an expert on patents, and had earlier drawn the patent drawings for Alexander Graham Bell's telephone.