Objective Lens Actuator with Two Lenses Aligned in Radial Direction for Ultra-slim Type BD Drive

Abstract

A new objective lens actuator for an ultra-slim type Blu-ray Disc drive was developed. The actuator has a configuration in which two objective lenses mounted on a holder of the moving part are aligned in the radial direction of the disc. This radial direction layout of two lenses reduces the distance in the tangential direction between each objective lens center and the gravity center of the moving part. Therefore, the amplitude at the pitching mode resonance frequency can be decreased. Calculated pitching phase deviation of the developed actuator is under 15° in the conditions of driving force center displacement of 0.3 mm, gravity center displacement of 0.05 mm, and objective lens center displacement of 0.1 mm.