| 摘要 |
An illumination system including at least one light source such as an electroluminescent element, e.g. a light emitting diode (LED), and at least one optical element whose surface is structured by diffraction and/or refraction type optical microstructures. In order to shape the beam, the optical element includes at least two sections whose optical microstructures and therefore optical properties are different from one another. The pattern of the microstructures in each of the at least two sections is, at least over a predetermined angular range, rotationally symmetric with respect to the optical axis or another symmetry axis. |
| 主权项 |
1. A flash light for a camera of a mobile communication device comprising an illumination system, said illumination system comprising at least one light source and at least one optical element that influences light emitted by the at least one light source, the light source and the optical element being arranged along an optical axis, wherein the optical element has a first surface directed towards the light source and a second surface pointing away from the light source, wherein at least one of said first and second surfaces is structured by at least one of diffraction and refraction type optical microstructures, and wherein the optical element comprises at least eight sections having the shape of a sector of a circle with a symmetry axis corresponding to the optical axis, wherein at least two of said sections have optical microstructures which are different from each other, and a pattern of the optical microstructures in said at least two sections is, at least over a predetermined angular range, rotationally symmetric with respect to at least one symmetry axis and wherein the at least one symmetry axis is parallel to, but spaced from, the optical axis, and wherein at least a first pair of said sections comprises a first pattern of microstructures, a second pair of said sections comprises a second pattern of microstructures, and a third pair and a fourth pair of said sections comprise a third pattern of microstructures, the optical element having rotational symmetry of order two. |
