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Optical disc device

A technology of an optical disc device and a light detection device, which is applied to the configuration/installation of the head, optical recording/reproduction, instruments, etc., and can solve problems such as inability to perform stable retrieval and large focus deviation

Inactive Publication Date: 2004-11-03
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the search of the track, under the influence of the transverse groove, the focus deviation becomes large, and stable search cannot be performed

Method used

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  • Optical disc device
  • Optical disc device
  • Optical disc device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0116] Below with Figure 1, figure 2 and Figure 10-Figure 12 , Figure 18 , Figure 23 The focus jump operation for moving from a certain information plane to another information plane in the optical disc apparatus according to the first embodiment of the present invention will be described. Among them, a two-layer disc having two information planes of L0 and L1 will be used in the description. However, it should be understood that this embodiment is also applicable to discs having more than two information planes, and will not be limited by the description of having two information planes.

[0117] Figure 10 It is a block diagram showing in detail the tracking control part in the DSP129 of Fig. 1; Figure 11 It is a waveform diagram showing the FE signal when the focus jumps from L0 to L1 and from L1 to L0, and the positive and negative pulse signals FEJMP pulse and TE signal generated by the waveform generator and applied to the focus control system.

[0118] Figu...

Embodiment 2

[0134] The optical disc device according to the second embodiment of the present invention can operate stably with respect to jumping of the disc or the like, and its configuration and operation will be described below.

[0135] As mentioned above, it is desirable to control the reflectance of L0 and L1 so that the amount of return light from L0 and L1 is approximately equal. property, the amount of return light from L0 and L1 will vary. This variation in the amount of returned light appears as a variation in the FE signal, the AS signal, or the RF signal as it is.

[0136] Once the amplitude of the FE signal deviates, when the information plane is moved under the focus jump, the gain of the focus control system changes, the lead-in becomes unstable, and the deviation becomes larger, which will affect the detection of the lead-in level of the target information plane. If it is falsely detected and becomes undetectable, stable movement cannot be performed.

[0137] Therefore,...

Embodiment 3

[0144] In the third embodiment of the present invention, similar to the above-mentioned second embodiment, the focus jump can be performed stably even against variations in the disc, etc., and its configuration and operation will be described below.

[0145] Therefore, in fact, since the deviation in the amount of return light from L0 and L1 is a deviation in the amplitude of the FE signal, AS signal, or RF signal as it is, the amplitude of the AS signal, RF signal, or its envelope detection signal is different from that of the FE signal. The amplitude is proportional to . Thus, the amplitude of the FE signal can be easily estimated from the amplitude of the AS signal, RF signal or its envelope detection signal.

[0146] In this way, in the present embodiment 3, when focusing is introduced on a 2-layer disc, two AS signals corresponding to L0 and L1 appearing synchronously with the S signal of the FE signal (not shown, see Figure 4 ) or the amplitude of the S-shaped signal o...

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Abstract

To realize high-speed and stable focus control of a two-focus head or a disk, having a plurality of information surfaces. In starting or restarting of a system, when a focal lens is moved close to a disk and then moved away from it, or moved away from the lens and then moved close to it; the amplitude of a S-shaped signal is measured, which appears on FE each time the focal point of the optical beam passes through each information surface, the gain of a focus detection system is switched such that the amplitude becomes a predetermined value, and thus an optimum drawing level is established. Then, when the lens is moved away from the disk from the uppermost point, or when it is moved close to the disk from the lowermost point, the focus control is operated on the information surface to which the focal point of the optical beam initially reaches and the drawing is completed. Thereafter, once the focus control is set inactive, the speed of the focal lens is increased / decreased, based on the FE signal level and the drawing level established on each information surface, and then the control is shifted to the next information surface.

Description

[0001] This application is a divisional application of the invention whose application number is "96113227.2", the application date is July 26, 1996, and the invention title is "optical disk device". technical field [0002] The present invention relates to an optical recording and reproducing device which optically records a signal on a recording medium using light beams from a light source such as a laser and reproduces the recorded signal. An optical recording and reproducing apparatus for controlling the converging state of a light beam on a recording medium to a predetermined converging state. Background technique [0003] As an existing optical recording and reproducing device, as recorded in Japanese Patent Laid-Open Publication No. 7-129968, it is an optical recording and reproducing device that condenses and irradiates light beams generated by light sources such as semiconductor lasers. The signal is recorded and reproduced on a disk-shaped recording medium rotating...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11B7/00G11B7/085G11B7/09
CPCG11B2007/0013G11B7/0945G11B2007/0006G11B7/08511G11B7/08
Inventor 渡边克也守屋充郎山田真一枝广泰明山元猛晴
Owner PANASONIC CORP