Laser texture apparatus using laser diode [hard disks]

A laser diode (LD) is used for a laser texture apparatus to form bumps on the Ni-P plated aluminum substrate for hard disks. The laser diode module of the apparatus comprises a LD, a collimator lens, a polarization beam splitter, a quarter wave plate and an objective lens for irradiating a pulsed laser beam on a surface on the substrate. The power of the LD is 300 mW and the numerical aperture of the objective lens is 0.8 for applying high power density. The shape of the bumps made by the apparatus is similar to that of the bumps made by laser texture apparatus comprising a high power continuous wave laser and an electro-optic modulator. The bump height is adjustable from 10 nm to 35 nm by changing the scanning length and the spindle speed.