KR100265414B1 - Multilayer compact disc and information detecting apparatus thereof using 3d multiple-wavelength whispering gallery laser - Google Patents

Abstract

PURPOSE: A data detector of a multiple layer CD(Compact Disk) is provided to save a large capacity of data by forming multiple track layers of a CD. CONSTITUTION: A 3D multiple wavelength whispering gallery laser(30) emits various kinds of laser beams(ray1,ray2) having different wavelength at different angles. A first and a second photodetector(PD1,PD2) detect the laser beams reflected from tracks in a first(L1) and a second layer(L2) of a double layer CD(32). Thereby, data recorded on two layers of the double layer CD are read out at the same time to promote synchronous parallel signal processing. In addition, to improve efficiency, NBRC(Narrow Band Reflective Coating) of the first and second laser beam is performed under the first and second layer. All of the first laser beam is reflected from the first layer, and data on the first layer are transferred to the first photodetector. Most of the second laser beam is transmitted from the first layer and is incident to the second layer. The second layer data are transferred to the second photodetector through the second layer.

Description

Multilayer compact disc and information detecting apparatus using using 3D multiple-wavelength whispering gallery laser}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact disc, and in particular, to form a plurality of track layers of a compact disc to store a large amount of information, and to track each layer using a 3D multi-wavelength whispering gallery laser. The present invention relates to a multi-layer compact disc information detection apparatus using a multi-layer compact disc and a three-dimensional multi-wavelength whispering gallery laser for reading out information stored in the apparatus.

To date, compact discs (CDs) have a huge market of 120 million CD players and 3 billion CDs in the United States alone. It is expanding to more and more applications such as video games. However, the conventional CD has a problem that can not store a large amount of information of more than 1 gigabyte. Therefore, it is required to dramatically increase the information capacity of the existing CD.

An object of the present invention is to provide a multi-layer compact disc capable of storing a large amount of information by forming multiple track layers of a compact disc.

Another technical problem to be achieved by the present invention is a multi-layer compact using a three-dimensional multi-wavelength whispering gallery laser for reading information stored in tracks of each layer of a multi-layer compact disc using a three-dimensional multiwavelength whispering gallery laser. It is to provide a disk information detection device.

FIG. 1A is a diagram illustrating a three-dimensional multi-wavelength vertical cavity whispering gallery laser, and FIG. 1B is a diagram illustrating wavelengths of lasers emitted according to an angle θ.

2 is a diagram illustrating a multilayer compact disc according to an embodiment of the present invention.

3 is a diagram illustrating a multi-layer compact disc information detection apparatus using a three-dimensional multi-wavelength vertical cavity whispering gallery laser according to an embodiment of the present invention.

4 is a view showing another embodiment of a multi-layer compact disc information detection apparatus using a three-dimensional multi-wavelength whispering gallery laser according to the present invention.

FIG. 5 illustrates a multiple polarization array using multiple polarization characteristics of a three-dimensional multiwavelength whispering gallery laser.

<Description of the code | symbol about the principal part of drawing>

L1-LN ... 1st layer-Nth layer,

C1 to CN ... First narrowband reflective coating to Nth narrowband reflective coating.

In order to achieve the above object, a multilayer compact disc according to the present invention includes a first layer provided with a plurality of tracks; And a second layer having a plurality of tracks stacked on the first layer, a first narrowband reflective coating below the first layer reflecting light of a first wavelength and transmitting light of a second wavelength And a second narrowband reflective coating for reflecting light of a second wavelength is provided below the second layer.

In addition, the multi-layer compact disc according to the present invention for achieving the above object, the first layer is provided with a plurality of tracks; And a second layer to an Nth layer having a plurality of tracks sequentially stacked on the first layer, and when n is an integer equal to or greater than 1 (N-1), an nth lower portion of the nth layer An nth narrowband reflecting coating is provided to reflect light of a wavelength and transmits light of an n + 1th wavelength, and an Nth narrowband reflecting coating to reflect light of an Nth wavelength is provided below the Nth layer. It is characterized by that.

In addition, the multi-layer compact disc according to the present invention for achieving the above object, the first layer is provided with a plurality of tracks; And a second layer to an Nth layer having a plurality of tracks sequentially stacked on the first layer, and when n is an integer of 1 or more and N or less, polarization of light of the nth wavelength is below the nth layer. And an n-th polarizing reflective coating that provides strong reflection in the direction.

Multi-layer compact disc information detection apparatus using a three-dimensional multi-wavelength whispering gallery laser according to the present invention to achieve the above another object, three-dimensional multi-wavelength that generates a plurality of laser beams having different wavelengths in a single laser at different angles Whispering gallery laser; And a plurality of laser beams that are reflected after the plurality of laser beams generated by the three-dimensional multi-wavelength whispering laser are irradiated to tracks in each layer of the multilayer compact disc having a narrowband reflection coating portion below each layer. And a plurality of light detectors for detecting each.

In addition, the multi-layer compact disc information detection apparatus using a three-dimensional multi-wavelength whispering gallery laser according to the present invention to achieve the above another object, multiple polarization of a plurality of laser beams having different polarization characteristics in a single laser at different angles An array unit; And detecting a plurality of laser beams reflected after the plurality of laser beams generated by the multi-polarization array unit are irradiated onto tracks in each layer of the multilayer compact disc having a polarizing reflective coating under each layer. It characterized in that it comprises a plurality of photo detectors.

The multi-polarization array unit is a three-dimensional multi-wavelength whispering gallery laser for generating a plurality of laser beams having different polarization characteristics; And a plurality of light transmitting parts which input and output each laser beam generated by the three-dimensional multi-wavelength whispering laser for each polarization characteristic.

Hereinafter, exemplary embodiments of a multilayer compact disc information detecting apparatus using a multilayer compact disc and a three-dimensional multi-wavelength whispering gallery laser according to the present invention will be described with reference to the accompanying drawings.

FIG. 1A illustrates a 3D multi-wavelength whispering gallery laser using a 3D vertical-cavity surface-emitting laser (3D VCSEL) structure. FIG. 1B is a diagram showing the wavelength of the emitted laser according to the angle θ.

Referring to FIGS. 1A and 1B, a three-dimensional multiwavelength three-dimensional multiwave whispering gallery laser 10 emits a multi-wavelength laser beam from a single laser, and as a result of experiments, different wavelengths vary depending on an angle θ with the optical fiber 12. It can be seen that it emits a laser beam of.

The multi-layer compact disc information detecting apparatus using the multi-layer compact disc and the three-dimensional multi-wavelength whispering gallery laser according to the present invention uses the multi-wavelength radiation characteristics of the three-dimensional multi-wavelength whispering gallery laser as described with reference to the accompanying drawings. An embodiment according to the invention will be described in detail.

2 shows a multilayer compact disc according to the invention. The multilayer compact disc shown in FIG. 2 has a first layer L1 having a plurality of tracks and a second layer to an Nth layer LN having a plurality of tracks sequentially stacked on the first layer L1. ). In addition, when n is an integer equal to or greater than 1 (N-1), an n-th narrow band reflection coating part Cn reflecting light of the nth wavelength and transmitting light of the n + 1th wavelength to the lower portion of the nth layer. ) Is provided, and an N-th narrowband reflecting coating (CN) for reflecting light of the N-th wavelength is provided below the N-th layer. This will be described with reference to FIG. 3.

Figure 3 shows an embodiment of a multi-layer compact disk information detection apparatus using a three-dimensional multi-wavelength whispering gallery laser according to the present invention, a narrow-band reflective coating (C1, C2) at the bottom of each layer as a multilayer compact disk Is an embodiment in the case of using the double-layer compact disc 32 is provided.

The apparatus of FIG. 3 is generated by a three-dimensional multiwavelength whispering gallery laser 30 and a three-dimensional multiwavelength whispering gallery laser 30 which generate different types of laser beams ray1 and ray2 having different wavelengths from different angles. Different types of laser beams ray1 and ray2 are irradiated to the tracks in the first layer L1 and the tracks in the second layer L2 of the dual layer compact disc 32, respectively, and are reflected by the laser beams ray1 and ray2. And first and second photodetectors PD1 and PD2 for detecting the light emission.

In the exemplary embodiment of FIG. 3, since a conventional compact disc has only one layer, and thus there is a limitation in the storage capacity of information, a dual-layer compact disc composed of two layers of first and second layers L1 and L2 ( 32). In addition, a three-dimensional multiwavelength whispering gallery laser 30 is used to generate a laser beam of different wavelengths at different angles in order to read information contained in two layers of tracks. First and second photodetectors PD1 and PD2 were used to detect the laser beams ray1 and ray2.

Here, the three-dimensional multi-wavelength whispering gallery laser 30 generates laser beams of different wavelengths in the range of 30 nm depending on the angle. The wavelength [lambda] is given by the following equation (1) by the non-vertical incident Fabry-Perot condition.

Where λο is the wavelength of the vertical cavity laser beam and n is the refractive index of the laser active layer. For example, when λο is 795 nm, the output wavelength λ varies from 795 nm to 764 nm, while the angle θ varies from 0 degrees to 90 degrees.

Accordingly, different angles θ1 and θ2 are determined as shown in FIG. 2, so that the first laser beam ray1 having the first wavelength λ1 is incident on the track of the first layer L1, and the second wavelength λ2. A second laser beam ray2 having a) is allowed to enter the track of the second layer L2. In addition, the laser beams reflected from the tracks of the respective layers are detected using the first and second photodetectors PD1 and PD2, respectively. In this way, the information amount of the existing compact disc can be doubled. In addition, the first laser beam ray1 and the second laser beam ray2 generated by the three-dimensional multi-wavelength whispering gallery laser 30 are the first layer L1 and the second layer L2 of the dual-layer compact disc 22. By reflecting from each track of the track and simultaneously detecting it in the first photodetector PD1 and the second photodetector PD2, information stored in two layers of the dual-layer compact disc 32 can be read out simultaneously and simultaneously Signal processing is possible. In addition, in order to increase efficiency, a narrow band reflective coating (NBRC) is applied to the first laser beam ray1 having the first wavelength under the first layer L2, and the second layer L2 is applied. Narrow-band reflective coating for the second laser beam (ray2) having a second wavelength on the lower surface of the), the first laser beam (ray1) is totally reflected in the first layer (L1) to provide information to the first photodetector Transmits to PD1, the second laser beam ray2 is almost transmitted through the first layer L1, enters the track of the second layer L2, reaches the second layer L2, and reaches the second layer L2. Information on the track of the N-axis is transmitted to the second photodetector PD2. Such narrowband reflective coatings are optional for double-layer compact discs, and in the case of multi-layer compact discs, narrowband reflective coatings are applied to each layer to increase efficiency while eliminating the loss of diffuse reflection generated in each layer.

4 is a generalization of the concept of FIG. 3 and illustrates an apparatus for detecting information of a multilayer compact disk having N layers as a multilayer compact disk.

The multilayer compact disc 42 may include a first layer L1 having a plurality of tracks and a second layer L2 to an Nth layer having a plurality of tracks sequentially stacked on the first layer L1. LN), where n is an integer equal to or greater than 1 (N-1), the lower portion of the nth layer Ln reflects the laser beam of the nth wavelength and the laser beam of the n + 1th wavelength An nth narrowband reflecting coating part (Cn) for transmitting is provided, and an Nth narrowband reflecting coating part (CN) for reflecting a laser beam of the Nth wavelength is provided below the Nth layer (LN). .

Reference numeral 40 denotes a three-dimensional multi-wavelength whispering gallery laser for generating N kinds of laser beams ray1, ..., rayN, and PD1 to PDN denote first to Nth photodetectors.

Meanwhile, FIG. 5 illustrates a multi-polarization array using the multi-polarization characteristics of the three-dimensional multiwavelength whispering gallery laser. The laser beam generated by the three-dimensional multiwavelength whispering gallery laser 52 is polarized because the output direction is radially symmetric. A laser beam is produced in which the characteristic 54 is polarized differently from 0 degrees to 360 degrees. Thus, using the multiple polarized outputs as shown, using optical fiber 50 or other separate optics, another multilayer compact disc can be fabricated. For example, in the case of a dual-layer compact disc using the polarization characteristics of a three-dimensional multiwavelength whispering gallery laser, a polarization sensitive reflective coating at the bottom of the first layer provides a strong reflection in the polarization direction of the first laser beam ray1. coating: PSRC), and the lower part of the second layer may be a polarizing reflective coating that provides strong reflection in the polarization direction of the second laser beam ray2. In the case of a double-layer compact disc having such a structure, the first laser beam ray1 is reflected by the first layer and transmitted to the first photodetector PD1, and the second laser beam ray2 passes through the first layer and then the second laser beam ray1 is transmitted. By reaching the layer, it is reflected by the coding surface of the underside of the second layer and transmitted to the second photodetector PD2 so that desired information can be read out in a simultaneous parallel processing manner.

As described above, the multi-layer compact disc information detecting apparatus using the multi-layer compact disc and the three-dimensional multi-wavelength whispering gallery laser according to the present invention can form multiple track layers of the compact disc and store information in large quantities. The information stored in the tracks of each layer of the layer compact disc can be read out in a simultaneous parallel process.

Claims (3)

When the first layer is provided with a plurality of tracks, and the second to Nth layer having a plurality of tracks sequentially stacked on the first layer, n is an integer of 1 or more (N-1) or less And an n-th narrow band reflective coating for reflecting light of an n-th wavelength and transmitting light of an n + 1th wavelength under the n-th layer, and light of an N-th wavelength is provided below the n-th layer. An apparatus for detecting information from a compact disc provided with an Nth narrowband reflective coating for reflecting, A three-dimensional multi-wavelength whispering gallery laser for generating a plurality of laser beams of different wavelengths in a single laser from the multilayer compact disc at different angles; And The plurality of laser beams generated by the three-dimensional multi-wavelength whispering laser are irradiated to the tracks in each layer of the multilayer compact disc having a narrow band reflection coating on the bottom of each layer, and then the plurality of laser beams are reflected. A multi-layer compact disc information detection apparatus using a three-dimensional multi-wavelength whispering gallery laser, characterized in that it comprises a plurality of photo detectors for detecting each. A nth layer including a first layer having a plurality of tracks, and a second layer to an Nth layer having a plurality of tracks sequentially stacked on the first layer, wherein n is an integer of 1 or more and N or less; An information detecting apparatus for detecting information from a multilayer compact disc having an n-th polarizing reflective coating that provides a strong reflection in the polarization direction of light of n-th wavelength at the bottom of the layer. A multiple polarization array unit for generating a plurality of laser beams having different polarization characteristics in a single laser to the multilayer compact disc at different angles; And Detecting a plurality of laser beams that are reflected after the plurality of laser beams generated by the multi-polarization array unit is irradiated to the tracks in each layer of the multilayer compact disc having a polarizing reflective coating on the bottom of each layer Multi-layer compact disc information detection apparatus using a three-dimensional multi-wavelength whispering gallery laser, characterized in that it comprises a plurality of photo detectors. The method of claim 2, The multi-polarization array unit is a three-dimensional multi-wavelength whispering gallery laser for generating a plurality of laser beams having different polarization characteristics; And And a plurality of light transmitting parts which input and output each laser beam generated by the three-dimensional multi-wavelength whispering laser for each polarization characteristic, and comprises a three-dimensional multi-wavelength whispering gallery laser.

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