US 6,643,303 B2 · Laser drive device, optical head, and optical information processor

Abstract

To provide a laser driving apparatus which is inexpensive and has high reliability in spite of using a plurality of light sources, since a multi-wavelength light source is required for treating different kinds of optical disks such as CD, DVD or the like. In a two-wavelength LD apparatus including: a semiconductor laser 1a; a semiconductor laser 1b; and a photo detector 2, optical outputs of the semiconductor lasers 1a, 1b are controlled by APC circuits 6a, 6b on the basis of respective voltage values of variable resistors 4a, 4b connected in series to the photo detector 2. Alternatively, in the two-wavelength LD apparatus including: the semiconductor laser 1a; the semiconductor laser 1b; and the photo detector 2, the optical outputs of the semiconductor 1a, 1b are controlled by the APC circuits 6a, 6b on the basis of respective intermediate potentials of variable resistors 4a, 4b connected in parallel with the photo detector 2.

Claims9

Dependent claims

A laser driving apparatus comprising:

n laser light sources L1 to Ln in which n is a natural number equal to or larger than 2;
a photodetector detecting rays emitted from said n laser light sources;
n variable resistors VR1 to VRn connected to said photodetector;
a voltage detector detecting n different values of voltages V1 to Vn related to said n variable resistors;
a controller controlling outputs of said laser light sources so that the detected voltage values are maintained at predetermined values, and
said n variable resistors VR1 to VRn are connected in series to one another, wherein
each of the n different values of voltages V1 to Vn detected is a voltage across both ends of one variable resistor within said n variable resistors, or a voltage across both ends of a serial circuit including at least two resistors within said n variable resistors.

4 more elements

A laser driving apparatus comprising:

n laser light sources L1 to Ln in which n is a natural number equal to or larger than 2;
a photodetector detecting rays emitted from said n laser light sources;
n variable resistors VR1 to VRn connected to said photodetector;
a voltage detector detecting n kinds of voltages V1 to Vn related to said n variable resistors;
a controller controlling an output of said laser light sources so that a detected corresponding voltage value has a predetermined value, and
a group of variable resistors within said n variable resistors are connected in series to one another and another group of variable resistors within said n variable resistors are connected in parallel with one another,
wherein for the group of variable resistors connected in series, each of different values of voltages detected is a voltage across both ends of one variable resistor within said group of variable resistors connected in series, or a voltage across both ends of a serial circuit including at least two resistors within said n variable resistors, and
wherein for the other group of variable resistors connected in parallel, said voltage detecting means detects voltages of middle potentials of the variable resistors connected in parallel relative to a reference voltage.

5 more elements

Dependencies are inferred from the claim text.

Laser drive device, optical head, and optical information processor

Life of this patent

Laser drive device, optical head, and optical information processor

Life of this patent

Abstract

Claims9