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Optical pickup device and optical disc device

A technology of optical pick-up and laser, which is applied in the direction of beam guiding device, optical recording head, optical recording/reproduction, etc., can solve the problems of increased number of components and cost, increased proportion of stray light, complicated adjustment of component configuration, etc. Achieve the effect of simple composition

Inactive Publication Date: 2012-02-08
SANYO ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] According to the technology of the above-mentioned Patent Document 1, it is necessary to accurately position the pinhole at the converging position of the laser light (signal light) reflected from the target recording layer, so there is a problem that the positioning operation of the pinhole is difficult.
If the size of the pinhole is increased for ease of positioning, the proportion of stray light passing through the pinhole increases, and signal degradation due to stray light cannot be effectively suppressed
[0010] In addition, according to the technology of Patent Document 2, in order to remove stray light, in addition to two 1 / 2 wavelength plates and two polarizing optical elements, two lenses are required, so the number of elements and cost increase, and the arrangement of each member is adjusted. complex problems exist
In addition, space is required for arranging and arranging these components, and there is also a problem of increasing the size of the optical system.

Method used

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  • Optical pickup device and optical disc device
  • Optical pickup device and optical disc device
  • Optical pickup device and optical disc device

Examples

Experimental program
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change example 1

[0109] In the above example, in Figure 5 Under the effect of astigmatism and change of traveling direction shown in (a), the light beams of signal light and stray light 1, 2 become Figure 5 (b) Such a distribution that such a beam is Figure 6 (b) shows the sensor pattern received. In this modified example, with the help of Figure 5 (a) Different astigmatism action and traveling direction changing action so that the light beams of signal light and stray light 1, 2 do not overlap each other on surface S0.

[0110] Figure 11 (a) is a figure which shows the structure of the anamorphic lens of this modification. The anamorphic lens of this modified example is divided into six regions around the optical axis. Areas A and D have an angle of 90 degrees in the circumferential direction (also referred to as the circumferential direction), and areas B, C, E, and F have an angle of 45 degrees in the circumferential direction. Each area has the same astigmatic function and the f...

change example 2

[0126] This modification uses the same Figure 11 (a) Different anamorphic lenses, so that the beams of signal light and stray light 1, 2 do not overlap.

[0127] Figure 14 (a) is a figure which shows the structure of the anamorphic lens of this modification. The anamorphic lens of this modified example is divided into 8 areas around the optical axis. The angle in the circumferential direction of each area is 45 degrees, and each has an astigmatism function and a traveling direction changing function as in the above-mentioned embodiment.

[0128] Regarding the astigmatism function, each of the regions A to H is designed so that, among the two boundaries between the other two adjacent regions around the optical axis of the laser light, not only the direction parallel to one boundary (plane direction) converging the light beams in the figure 1 The focal line position (S2) of (a) forms a focal line, and the beams are converged in a direction perpendicular to the boundary to ...

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Abstract

The invention provides an optical pickup device and an optical disc device, which can effectively remove stray light by a simple construction. The optical pickup device imparts different astigmatisms from each other to light fluxes in four light flux areas A through D formed around an optical axis of laser light, out of the laser light reflected on a disc. The optical pickup device also changes the propagating directions of the light fluxes in the light flux areas A through D to separate the light fluxes in the light flux areas A through D from each other. A signal light area where only signal light exists is defined on a detection surface of a photodetector. Sensing portions are arranged at a position corresponding to the signal light area. Accordingly, only the signal light is received by the sensing portions, thereby suppressing deterioration of a detection signal resulting from stray light.

Description

technical field [0001] The present invention relates to an optical pickup device and an optical disc device, and is particularly suitable for use when irradiating a recording medium on which a plurality of recording layers is laminated with laser light. Background technique [0002] In recent years, along with the increase in the capacity of optical discs, multi-layer recording layers have been advanced. By including a plurality of recording layers in one disc, the data capacity of the disc can be significantly increased. In the case of stacking recording layers, conventionally, one side is double-layered, but recently, in order to further increase the capacity, an optical disk having three or more recording layers on one side has been studied. Here, if the number of stacked recording layers is increased, an increase in the capacity of the disc can be promoted. On the other hand, however, as the interval between recording layers becomes narrower, signal degradation due to ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11B7/135G11B7/00
CPCG11B7/0909G11B2007/0013
Inventor 永富谦司
Owner SANYO ELECTRIC CO LTD