| 摘要 |
A depolarization element includes high depolarization for light beams having coherence and plural wavelengths and also provides a projection type display device capable of reducing speckle noise. Unit regions, each formed of m regions (m≧4) having different phase differences generated for incident light, are disposed, and two regions extracted from the m regions have at least one combination of regions being different in area. When plural light beams having different wavelengths are incident, the composition of the Stokes vectors of the light beams emitted from the respective m regions is made nearly zero by setting the areas of the respective m regions and the generated phase differences, whereby the light beams having coherence and plural wavelengths can be converted so as to have the polarization state of natural light. |
