Unlock instant, AI-driven research and patent intelligence for your innovation.

Optical diffraction device and optical information processing device

A light diffraction and device technology, which is applied in the field of light diffraction devices, can solve problems such as CD becoming 0, focusing and tracking control adverse effects, and no polarization dependence.

Inactive Publication Date: 2006-04-19
PANASONIC CORP
View PDF2 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0070] As mentioned above, the device disclosed in JP-A-2001-14714 ( Figure 11 ) can efficiently guide short-wavelength DVD light to the disc surface, but since the polarizing hologram 109 is used, the signal from the CD may become zero due to the influence of the birefringence of the disc substrate.
This not only affects the reading of the RF signal, but also has a bad effect on the focus and tracking control
[0071] In addition, the device disclosed in JP-A-2000-76689 ( Figure 12 ), since the holograms 126 and 127 do not have polarization dependence, they are not affected by the birefringence of the disc substrate, but there is a problem of low light transmission efficiency
[0072] In this way, there has never been a hologram (light diffraction device) that exhibits high light transmission efficiency during the round trip of light and is not affected by the birefringence of the optical disc substrate.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Optical diffraction device and optical information processing device
  • Optical diffraction device and optical information processing device
  • Optical diffraction device and optical information processing device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0166] First, compare Figure 2 to Figure 5 , the first embodiment of the optical information processing apparatus according to the present invention will be described. The optical information processing apparatus of the present embodiment is an optical pickup including the optical diffraction device of the present invention. figure 2 The overall configuration of the optical pickup is shown in .

[0167] figure 2 The optical pickup is used in an optical disc device capable of writing data to and / or reading data from various optical discs. During the recording and reproducing operation, the optical disc device is rotated by a drive unit (not shown) such as a motor in the optical disc device.

[0168] The optical pickup of the present embodiment includes a light source for forming a plurality of light beams with different wavelengths, an objective lens for condensing the light beams to form light spots on the signal surface of the optical disc, and a light diffractive devic...

Embodiment approach 2

[0240] control Image 6 (a) to (c), the second embodiment of the optical diffraction device according to the present invention will be described.

[0241] Image 6 (a) is a cross-sectional view illustrating a configuration of a polarizing device including the optical diffraction device and the wave blocking plate of the present embodiment.

[0242] This polarizer includes a first glass substrate 15, a thin film periodic structure 16 formed on the glass substrate 15, an isotropic medium 17 formed on the glass substrate 15 to cover the thin film periodic structure 16, and an isotropic medium 17 provided on the isotropic medium 17. The wave blocking plate 21 on the top and the second glass substrate 14 provided on the wave blocking plate 21 . Here, the thin-film periodic structure 16 has refractive index anisotropy, and the wave blocking plate 21 is formed of a thin-film-like sheet.

[0243] The part of the diffraction grating of the above-mentioned polarizer is manufactured a...

Embodiment approach 3

[0265] control Figure 7 , another structure of the polarizing device having the optical diffraction device and the wave blocking plate of the present invention will be described.

[0266] The optical diffraction device of the present embodiment has a substrate 23 in which the refractive index anisotropy region 22 is periodically formed. The substrate 23 is formed of an anisotropic material such as lithium niobate, and the refractive index anisotropy region 22 is formed by proton exchange. A region whose polarity is reversed (thickness: d, proton exchange part) by methods such as .

[0267] The periodic structure of the substrate 23 is determined by the pair wavelength λ 1 The ordinary light and extraordinary light of , the refractive index is n respectively 0 , n 1 part of , and for wavelengths λ 1 The ordinary light and extraordinary light of , the refractive index is n respectively 01 , n 11 part of .

[0268] The above-mentioned numerical values ​​are set so as to s...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
thicknessaaaaaaaaaa
wavelengthaaaaaaaaaa
thicknessaaaaaaaaaa
Login to View More

Abstract

An optical diffraction device disposed in an optical path through which light beams having different wavelengths pass. The device has a periodical structure in which when, of the beams, a first light beam of wavelength lambda1 is linearly polarized along a first direction X, the first light beam is almost completely transmitted, and when the first light beam is linearly polarized along a second direction Y perpendicular to the first direction X, the first light beam is almost completely diffracted. Of the beams at least a part of the second beam having a wavelength lambda2 different from the first beam wavelength lambda1 is diffracted irrespective of its polarized state.

Description

technical field [0001] The present invention relates to a light diffraction device having different diffraction effects according to the wavelength and polarization state of light. In addition, the present invention relates to an optical information processing device capable of recording and / or reproducing data on various types of optical discs having different substrate thicknesses. Background technique [0002] In recent years, apparatuses for recording information on or reading information from recording media such as optical disks have become widespread. As recording media, CDs and DVDs are currently used, and optical disks based on new standards such as BD (Blu-Ray Disc) have also been developed. In this way, a variety of recording media are produced according to different standards, and specifications such as the wavelength of recording / reproducing light, recording density, recording capacity, and substrate thickness are different. However, a single device has been de...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G11B7/135G02B5/18G02B5/30G11B7/125
CPCG02B5/1809G11B7/1353G11B7/1275G02B5/18
Inventor 麻田润一西胁青儿
Owner PANASONIC CORP