OPTICAL COMPONENT HAVING WAVELENGTH SELECTING FUNCTION, AND OPTICAL PICKUP DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical component having a dichroic filter capable of enhancing the latitude of design by providing a phase adjusting layer capable of adjusting a phase while maintaining a desired transmittance characteristic for a wavelength on a specified layer constituting the dichroic filter and a reflection preventing film on the same optical plane and to provide an optical pickup device. SOLUTION: The optical component is provided with a substrate 10 and optical multi-layered films 12 on the substrate, consisting of plural optical layers having a wavelength selecting function for more transmitting light having on wavelength through the optical plane and more reflecting light having the other wavelength on the optical plane. The difference of the refractive index of an optical layer in contact with or the nearest to the substrate in the optical multi-layered film having the wavelength selecting function and the refractive index of the substrate is less than 0.3. A part 11 formed on the substrate and having no wavelength selecting function is the reflection preventing film having a refractive index and film thickness adjusted so as to have the reflection preventing function to the two used wavelength and consisting of at least one optical layer and layers 13 having a structure about equal to that of the reflection preventing film are disposed on an air side of the optical multi-layered films 12.