Double-layer CD reading head based on phase turnover

A read head, double-layer technology, applied in optical recording heads, beam guides, etc., can solve problems such as high cost and complex structure

Inactive Publication Date: 2004-02-04
SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Both structures of the above-mentioned prior art [2] and [3] have the problems of complex structure and high cost

Method used

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  • Double-layer CD reading head based on phase turnover
  • Double-layer CD reading head based on phase turnover
  • Double-layer CD reading head based on phase turnover

Examples

Experimental program
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Embodiment Construction

[0020] like Figure 4 In the structure shown, the laser light source 1 has a wavelength of 632.8nm. The illumination beam produced by the He-Ne laser is collimated by the collimator lens 2, and then passes through the first semi-transparent and semi-reflective beam splitter 3, and a beam of light transmitted by it passes through the first The phase plate 4 , the second beam splitter 7 , the third beam splitter 8 , and the lens 9 focus on the first layer of the double-layer optical disc 10 . After being reflected, pass through lens 9, the 3rd beam splitter 8 and the second beam splitter 7 imaging again on the receiving surface by charge coupler (CCD) as detector 6; Another bundle of reflected light passes through second reflector 14 and After two reflections by the first mirror 13 , the second phase plate 12 , the negative lens 11 , the third beam splitter 8 and the lens 9 are used to focus on the second layer of the double-layer optical disc 10 . After being reflected by the ...

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PUM

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Abstract

In the double-layer CD reading head based on phase turnover, the laser beam emitted by the laser source and through collimation lens is splited in the first beam splitter mirror, the transparent laser is made to pass through the first phase board, the second beam splitter mirror, the third beam splitter mirror and the objective and focused onto the first layer of the double-layer CD; and the reflected laser is made to pass through the second reflector, the first reflector, the second phase board, the negative lens, the third beam splitter mirror and the objective and is focused onto the second layer of the double-layer CD. The two laser beams join finally in the detector. The present invention has simple structure and can read precisely CD with relatively high storage density.

Description

technical field [0001] The invention relates to a read-out head for a double-layer optical disc based on phase inversion, in particular suitable for reading a double-layer digital video disc (referred to as DVD). Background technique [0002] The prior art [1] (see J.Taylor, DVD Demystified (McGraw-Hill, New York, 1997)) uses a dual-layer DVD reading system that first focuses on reading information on one layer, and then changes it mechanically. The focus is on the second level, because it is time-sharing reading, which affects the data reading speed. [0003] The prior art [2] (see S. Stankovic, et al, "Integrated optical pickup system for axialdual focus", Appl. ) system, so that it has different focal lengths for the two polarization states of the transverse electric mode (TE) and the transverse magnetic mode (TM), so that different layers can be read by using beams of different polarization states. [0004] Prior art [3] (see R.Katayama, et al, "Dual-wavelength optical...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11B7/135G11B7/14
Inventor 周常河赵帅刘立人
Owner SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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