Samsung Electronics Co., Ltd.

Yong-jun Cho

Pyong-yong Seong

Jong-koog Lee

Sung-du Kwon

Kun-soo Kim

Jun-Hyuk Lee

Hyun-cheal Bang

Eun-goo Kim

Seung-man Han

Hyun-seob Choi

Chun-gi Kim

Jung-koog Lee

An apparatus and method for detecting beam power generated by a plurality of light sources, using a single device. The apparatus includes a light-receiving unit that receives the beam power generated by one of a plurality of light sources, and an amplifying unit that selects a gain, amplifies the beam power received by the light-receiving unit according to the selected gain, and outputs the beam power amplified as a detected beam power. According to the apparatus and method, received beam power (or amplification gain) is amplified by a gain determined according to the characteristics of the respective light sources. Thus, it is possible to provide the detected beam power in consideration of a sufficient dynamic range for the each light source, thereby realizing effective APC.

Apparatus and method for detecting beam power in optical drive

In order to improve the frequency characteristic of a laser power monitor device and the precision of laser power control when low-speed recording is performed, there is provided a laser power monitor device for an optical recording and/or reproducing apparatus, the laser power monitor device including a photo diode unit to receive part of a light emitted from a laser diode and output a current proportional to optical power, and a monitor circuit to receive the current output from the photo diode unit, convert the received current into a voltage, and outputs the voltage to an automatic laser power control circuit, and the photo diode unit includes a plurality of photo diodes connected to the monitor circuit to supply current to the monitor circuit. The laser power monitor device further includes a switch unit, wherein the switch unit is located between the photo diode unit and the monitor circuit to receive a signal on a current recording speed and switch so that the number of photo diodes supplying current to the monitor circuit is reduced as the recording speed is increased.

Laser power monitor device, optical pickup including the same, and optical recording and/or reproducing apparatus including the same

An optical pickup for a recording medium includes a light source, an objective lens, a main photodetector, and a front photodetector. The configuration of the optical pickup enables converging or diverging of light to be incident on a plate beam splitter so that light can be received at an effective light receiving region of a front photodetector without interference due to internal reflection occurring in the plate beam splitter. In the alternative, a wedge beam splitter in the optical pickup includes first and second mirror planes at a predetermined angle to transmit and reflect incident light at a predetermined ratio. In the optical pickup, an amount of light that is exactly proportional to an output power of the light source can be detected, where the output power of the light source can be accurately controlled, thereby improving a linearity of the output power of the light source.

Optical pickup and a wedge beam splitter

A laser power control device for use in an optical recording and/or reproducing apparatus that records data on and/or reproduces data from an optical recording medium by driving a laser diode with a laser diode driver. The device includes: a peak power monitor which monitors a peak power by a sample-and-hold operation, the peak power being output by the laser diode when pits are formed in the optical recording medium; an elimination power monitor which monitors an elimination power by the sample-and-hold operation, the elimination power being output by the laser diode when a space between pits of the optical recording medium is formed; a peak power setter which sets a peak power in the laser diode driver based on a monitoring result of the peak power monitor; an elimination power setter which sets an elimination power in the laser diode driver based on a monitoring result of the elimination power monitor; and a bias power setter which sets a bias power in the laser diode driver based on the monitoring results of the peak power monitor and the elimination power monitor.

Laser power control device

Growing community of inventors

Gyeonggi-do, South Korea

Yong-jun Cho