Optical head and optical disc apparatus

A technology of optical disc device and optical head, which is applied in the direction of beam guiding device, optical recording head, head configuration/installation, etc., which can solve the problems of unstable amplitude fluctuation and achieve high signal amplification effect

Inactive Publication Date: 2012-01-11
HITACHI CONSUMER ELECTRONICS CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Generally, the amplitude of the interference signal obtained by the interference of two lights depends on the phase difference (optical path length difference) between the two interfering lights. Amplitude fluctuation becomes unstable

Method used

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  • Optical head and optical disc apparatus
  • Optical head and optical disc apparatus
  • Optical head and optical disc apparatus

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Embodiment 1

[0058] Use the following figure 1 Embodiments of the present invention will be described.

[0059] figure 1 This is the basic embodiment of the optical head of the present invention. The light from the semiconductor laser 101 is converted into parallel light by the collimator lens 102 , passes through the λ / 2 plate 103 , and enters the polarization beam splitter 104 . The polarization beam splitter 104 has a function of transmitting almost 100% of p-polarized light (hereinafter referred to as horizontally polarized light) incident on the splitting surface and reflecting substantially 100% of s-polarized light (hereinafter referred to as vertically polarized light). In this case, by adjusting the rotation angle of the rotation of the optical axis of the λ / 2 plate, the intensity ratio of transmitted light and reflected light can be adjusted. The reflected light (hereinafter referred to as signal light) enters the special polarization beam splitter 105 first. The special pola...

Embodiment 2

[0103] This embodiment is another embodiment in which signal light and reference light are separated again after being combined. Figure 10A structural diagram showing this embodiment. In this case, the signal light is reflected by the optical disc 110 and passes through the polarizing beam splitter 104 following the opposite optical path as in the first embodiment. On the other hand, the reference light passes through the λ / 4 plate (axial direction: 45 degrees relative to the horizontally polarized light), is condensed on the mirror 1003 through the lens 1002 and is reflected to follow the opposite optical path, and reciprocates through the λ / 4 plate 1001, As a result, the polarized light is rotated by 90 degrees and reflected by the polarization beam splitter 104 , at which point the signal light and the reference light are combined in a perpendicular state. The multiplexed light beams are brought into a condensed state by the lens 1004 and then separated in parallel by the...

Embodiment 3

[0107] The present embodiment is another embodiment in which branching is performed to interfere signal light and reference light with mutually different phases, and the process of combining the branched signal light and reference light is performed simultaneously. Figure 12 A structural diagram showing this embodiment. This embodiment is the same as the first embodiment until the signal light and the reference light pass through the λ / 2 plate (axial direction: 22.5 degrees relative to the horizontally polarized light) 115 . The signal light and reference light are combined by the polarization beam splitter 1201, and two combined beams are emitted. At this time, the polarization states of the signal light and the reference light are as follows: Figure 13 As shown, the horizontally polarized component of the signal light passes through the polarization beam splitter 1201 and is multiplexed with the vertically polarized component of the reference light. Likewise, the vertica...

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Abstract

The present invention provides an optical head and an optical disc apparatus. In an interference-type optical head and optical disc apparatus, accordance of optical axes of signal light of a reflective light form an optical information medium and a reference light interfered with the singal light is difficult, and interference light is hard to be generated with high accuracy. Reference light for interference with signal light from an optical information recording medium is displaced and reflected by a corner cube prism or the like with high accuracy. The signal light and the displaced reference light are made parallel with each other with high accuracy. The signal light and the reference light are each split using a polarization splitter to generate interference light. Thus, regeneration signals are stabilized. Accordingly, an interference-type optical head and optical disc apparatus of higher quality than conventional ones can be provided.

Description

technical field [0001] The present invention relates to a higher S / N of a reproduced signal of an optical disc device. Background technique [0002] With regard to optical discs, the resolution of the optical system has almost reached the limit at the stage when the Blu-ray disc using blue semiconductor lasers and high NA objective lenses has been commercialized. In the face of further increase in capacity, it is necessary to consider multi-layer recording layers in the future. effective. In such a multi-layer optical disk, since the detection light intensity from each recording layer needs to be substantially the same, the reflectance from a specific recording layer has to be reduced. However, since the increase in the capacity of the optical disk also requires an increase in the dubbing speed of video and the like, the increase in the speed of the data transfer rate is also continuing. In this case, the S / N ratio (signal noise ratio). Therefore, in order to simultaneous...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B7/09G11B7/135
CPCG11B7/1381G11B7/005G11B7/1359G11B7/0051G11B7/1356
Inventor 三上秀治
Owner HITACHI CONSUMER ELECTRONICS CORP
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