Patent ID: 7242444

Claim:
A method of manufacturing a microstructure element dividing a machining area into five or more sub-areas, said machining area being one of faces of an output-side dust-preventive transparent plate, and said sub-areas being of a band-shape; forming a first shape in a first any one of the sub-areas, said first shape composed of a flat portion and a refracting surface, said refracting surface being adjacent to said flat portion and formed in a V-shaped groove; forming a second shape at a another sub-area that is located farther from any one of the sub-areas than an adjacent area to the first any one of the sub-areas, taking another any one of the sub-areas as a new reference, wherein said second shape is also composed of a flat portion and a refracting surface formed adjacent to said flat portion in a V-shape and repeating the forming of other shapes in the same manner as that of forming the second shape, taking the another sub-area on which the second shape is formed as the new reference, wherein the first shape and the second shape are formed in different shapes from each other.