Laser diode module of optical scanner

A laser diode module of an optical scanner, comprising:

• a circuit board;
• a case fastened to a surface of the circuit board in a selected two-dimensional position thereon, the case having a laser diode embedded therein so as to produce a forwardly directed laser beam;
• a slider guide fastened to a front surface of the case and having a barrel shaped, upwardly directed guide surface which extends axially in a front-to-rear direction and a pair of further guide surfaces which are formed at either side of the barrel shaped guide surface and extend in a front-to-rear direction;
• a lens holder having a body and a pair of guide pieces, the body being seated on the barrel shaped guide surface of the slider guide such that it can slide thereon forward and backward and being formed with an inserting hole, the pair of guide pieces being on either side of the body and being seated on the pair of further guide surfaces of the slider guide;
• a collimator lens fitted into the inserting hole of the body of the lens holder for shaping laser beams emitted from the laser diode into parallel light beams;
• and
• a lens fastener fitted into the inserting hole of the body of the lens holder for preventing the collimator lens from shaking;
• and
• an upper cover coupled onto the slider guide such that it defines a shape which is symmetrical to the shape of the slider guide, for isolating the lens holder, the collimator lens and the lens fastener from the outside.