Patent ID: 7450476

Claim:
A light emitting module comprising: a base; a semiconductor laser that is disposed on the base and emits a laser beam of a predetermined wavelength; a cap surrounding the semiconductor laser; a beam shaping window that is fitted with a predetermined portion of the cap corresponding to the propagation path of the laser beam and shapes a transmitted laser beam while reflecting a portion of an incident beam; and a quarter wave plate that is disposed in the propagation path of the laser beam and in front of the beam shaping window and transforms a laser beam horizontally polarized after passing through the beam shaping window into a circularly polarized beam while converting a beam reflected from an optical disc into a vertically polarized beam; wherein the beam shaping window comprises a first surface that is inclined at an angle to an optical axis of the laser beam emitted by the semiconductor laser and refracts most of the beam emitted by the semiconductor laser in a direction perpendicular to a second surface and reflects the remaining portion of the beam; and wherein the second surface is perpendicular to the propagation direction of the beam refracted through the first surface and directs most of the beam emitted by the semiconductor laser.