Patent ID: 7742382

Claim:
A laser converging apparatus comprising: a polarizing hologram element having a first area defined by a numerical aperture corresponding to a thickness of a first protective layer of a first disk medium and a second area inside the first area, the second area defined by a numerical aperture corresponding to a thickness of a second protective layer of a second disk medium, the thickness of the second protective layer being greater than the thickness of the first protective layer, the second area having a hologram pattern for transmitting first laser light linearly polarized in a first direction without diffracting the first laser light while diffracting and transmitting second laser light that is linearly polarized in a second direction crossing the first direction, the second laser light having the same wavelength as the first laser light; an objective lens having the numerical aperture corresponding to the thickness of the first protective layer, the objective lens converging the first laser light having passed through the first area including the second area onto an information surface on one side of the first protective layer, the objective lens converging the second laser light having passed through the second area onto an information surface on one side of the second protective layer; and a holder that holds the polarizing hologram element and the objective lens.