Provided is an objective lens which is used so that more information can be accumulated in a large-capacity optical disk and which has a further enhanced numerical aperture NA. The objective lens is a single lens having the numerical aperture NA and a refractive index n, and is configured so as to satisfy: NA≥0.91 and 1.61≤n<1.72.

An optical pickup device includes a semiconductor laser that emits a laser beam, and an object lens that concentrates the laser beam emitted from the semiconductor laser on an optical disc. In this optical pickup device, an optical axis of the object lens is inclined with respect to an optical axis of the laser beam that is incident on the object lens so as to generate flares caused by coma aberration on an entrance side in a forward direction of pits of the optical disc.

A drawing method according to an embodiment of the present disclosure includes, when performing drawing on a thermal recording medium that includes a light-transmitting member above a recording layer, obtaining information regarding the light-transmitting member, predicting an optical axis deviation of a laser beam in the recording layer from the information regarding the light-transmitting member, and calculating a correction amount from a result of the prediction of the optical axis deviation.

An optoelectronic assembly is disclosed. The disclosed assembly includes one or more lasers formed on a first substrate, and a programmable driver circuit formed on a second substrate configured as an integrated circuit. The first and second substrates are mounted on a third substrate in a stacked arrangement.

A drawing method according to an embodiment of the present disclosure includes, when performing drawing on a thermal recording medium that includes a light-transmitting member above a recording layer, obtaining information regarding the light-transmitting member, predicting an optical axis deviation of a laser beam in the recording layer from the information regarding the light-transmitting member, and calculating a correction amount from a result of the prediction of the optical axis deviation.

Provided is an objective lens which is used so that more information can be accumulated in a large-capacity optical disk and which has a further enhanced numerical aperture NA. The objective lens is a single lens having the numerical aperture NA and a refractive index n, and is configured so as to satisfy: NA≥0.91 and 1.61≤n<1.72.

An optoelectronic assembly is disclosed. The disclosed assembly includes one or more lasers formed on a first substrate, and a programmable driver circuit formed on a second substrate configured as an integrated circuit. The first and second substrates are mounted on a third substrate in a stacked arrangement.

An optical disc device includes: an optical pickup including a first laser light source that emits laser light, an objective lens that focuses the laser light emitted from the first laser light source onto an optical disc, and a light receiving element that receives reflected light from the optical disc, and performs photoelectric conversion on the reflected light received to output a received-light signal; an FS signal generator that generates an FS signal indicating the light amount of the reflected light from the optical disc, based on the received-light signal from the light receiving element; and a dirt determiner that determines that dirt is present in the optical pickup, when the peak level of the FS signal is less than a dirt determination threshold, and controls the light receiving element to increase the peak level of the received-light signal from the light receiving element.

There are provided an optical disk from which high-density data is reproduced and a reproduction apparatus that reproduces data from such an optical disk having high-density data recorded thereon. A photo-detecting section has two split detectors A and B in the direction of tracks on the disk. A signal processing section generates a TPP (Tangential Push-pull) signal made of a differential signal derived from detection signals from the detectors A and B, and further generates a reproduced signal by extracting from the TPP signal a high-frequency component signal in a record signal recorded on the disk. The signal processing section reconstitutes a high-frequency component signal in the record signal recorded on the disk by frequency-shifting the TPP signal obtained as a readout signal from a superimposed signal having the carrier signal and the record signal superimposed with each other.

An optical disc device includes: an optical pickup including a first laser light source that emits laser light, an objective lens that focuses the laser light emitted from the first laser light source onto an optical disc, and a light receiving element that receives reflected light from the optical disc, and performs photoelectric conversion on the reflected light received to output a received-light signal; an FS signal generator that generates an FS signal indicating the light amount of the reflected light from the optical disc, based on the received-light signal from the light receiving element; and a dirt determiner that determines that dirt is present in the optical pickup, when the peak level of the FS signal is less than a dirt determination threshold, and controls the light receiving element to increase the peak level of the received-light signal from the light receiving element.