Optical pickup device and collimate lens

Abstract

It is possible to provide a small-size thin optical pickup device which can correct a coma aberration generated in a light collection optical system including an objective lens for an optical disc. The optical pickup device includes: a first coma aberration correction actuator (6) which has a first tilt drive unit for tilting the objective lens in a first tilt direction; and a second coma aberration correction actuator (7) which has a second tilt drive unit for tilting a coma aberration correction lens arranged between a light source and a start-up mirror for reflecting an outgoing light toward the objective lens, into a second tilt direction.

Description

technical field [0001] The present invention relates to an optical pickup device for reproducing information from an information recording medium typified by an optical disc or for recording information on an information recording medium, and a collimator lens equipped in the optical pickup device. Background technique [0002] A digital video disc (DVD) is known as an optical disc capable of recording large-capacity data because it can record digital information at a recording density about six times that of a read-only disc (CD). In recent years, as the amount of information to be recorded on an optical disc has increased, an optical disc with a larger capacity has been demanded. In order to increase the capacity of the optical disc, it is necessary to increase the recording density of information by reducing the size of the light spot formed by the light irradiated on the optical disc when recording information on the optical disc and when reproducing the information reco...

AI Technical Summary

Problems solved by technology

[0007] However, in a coma correction device using a liquid crystal element, there is a problem that only low-frequency angular deviation can be corrected, and it is difficult to reduce coma aberration generated in a wide range from low frequencies to high frequencies.

Therefore, the problem is that not only the mechanism is very complicated, but also there may be intermodulation distortion in the radial and tangential directions.

However, this situation is also the same as the case of the above-mentioned coma aberration correction transmission mechanism, and it is necessary to separately install the hangers in the radial direction and the tangential direction, which causes the problem that the resonance characteristics of the objective lens transmission mechanism are deteriorated, and the objective lens transmission mechanism is caused. upsizing

But, in this case, with regard to one objective lens, for example, the inclination of the objective lens can be adjusted and fixed when the objective lens actuator is installed on the optical pickup device; Tilt adjustment is performed without changing the positional relationship between the objective lens and the disc.

Moreover, these objective lenses are very small, and their position adjustment becomes a very difficult task

Therefore, a large-scale lens adjustment device and an adjustment work process are required.

[0017] In addition, in the above-mentioned BD, the information recording surface with a maximum of 2 layers is expected to increase in the future, and the distance between the information recording surface closest to the disc surface and the information recording surface farthest will be larger than it is now.

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