KR100205416B1 - Optical pickup device for different type optical disk - Google Patents

Abstract

The present invention relates to an optical pickup device for heterogeneous optical disks having different substrate thicknesses and wavelengths. In particular, a dichroic mirror is formed on one side, that is, a surface on which a beam having a wavelength for CD-R is incident. Light beams reflected from optical disks having different wavelengths and thicknesses by using NPBS coated with PBS or by attaching λ / 2 plates and coating dichroic mirrors on the λ / 2 plates. It can be detected using a detector, and all four sides of NPBS or PBS can be used, so that the space can be efficiently used, making it easy to reduce the thickness and weight of the optical pickup device and to reduce the price. Recording / playback compatibility becomes possible.

Description

Optical pickup device for different optical discs

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical pickup devices for heterogeneous optical discs having different substrate thicknesses and wavelengths, and particularly to compact discs (CDs) and digital video discs (DVDs) as well as recording in the same optical pickup device. The present invention relates to an optical pickup apparatus for heterogeneous optical discs, which enables recording / playback compatibility of a CD, that is, CD-R (Compact Disc Recordable).

The light source used for the optical pickup for DVD has a wavelength of 635 to 650 nm (visible light, red). A light source having a wavelength of 780 nm (infrared light) is required to simultaneously read a CD-R disc in the same player.

In other words, in the case of CD-R, the medium of the disc uses cyanine (blue pigment) dye, which has a property of having a reflectance only at 780 nm.

Therefore, since a light source of 780 nm is necessarily required, it cannot be used as a DVD light source.

At this time, the CD can be read at both 780 nm and 635 to 650 nm wavelengths.

As a result, in order to use a CD-R in a DVD player, a CD-R light source and a DVD light source are required, respectively. Therefore, a method of configuring two light sources in the same laser diode package and using the same pickup is proposed. have.

However, to actually use the same pickup, the distance between the two light sources must be close to within 100 nm, which is difficult to implement because the actual laser diode size itself exceeds this size.

In addition, in order to use CD-R in the optical pickup device for DVD, an optical detector for detecting the light beam reflected from the CD-based optical disk and an optical detector for detecting the light beam reflected from the DVD-based optical disk were required.

Therefore, since two optical detectors are required for one optical pickup device, the volume of the optical pickup device is large, making it difficult to reduce the thickness.

In this case, each of the photo detectors may be arranged side by side with the laser diode in the light source package to be integrated with the laser diode, or may be configured separately from the light source. In the case of the configuration, since the optical system configuration increases, there is a problem that the volume increases and the probability of error occurrence also increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to separately configure light sources having different wavelengths and to transmit or reflect beams according to the wavelength difference, thereby recording / recording of optical discs having different wavelengths. An optical pickup device for heterogeneous optical discs capable of playback compatibility.

Another object of the present invention is to coat a dichroic mirror on one side of a non-polarizing beam splitter (NPBS) that passes a certain amount of light beams and reflects the rest regardless of the wavelength or polarization direction. By using a single optical detector as well as using all of them, and detecting the reflected light beams from optical disks having different wavelengths and thicknesses, the size of the optical pickup device can be reduced and optical discs can be reproduced and compatible. In providing a pickup device.

Another object of the present invention is to attach a lambda / 2 plate on one side of a polarizing beam splitter (PBS) for transmitting or reflecting the incident beam in accordance with the polarization direction, the dichroic mirror on this lambda / 2 plate By placing a λ / 4 plate on the same optical path of the PBS and using all four sides of the PBS as well as detecting the reflected light beams from optical disks having different wavelengths and thicknesses using a single photo detector. An optical pickup apparatus for heterogeneous optical disks is provided in which the size of the pickup apparatus is reduced and the recording / playback compatibility of the optical disk is made possible.

A feature of the optical pickup device for heterogeneous optical disks according to the present invention for achieving the above object is that the first light source for emitting a beam of a first wavelength, and the light beam for emitting a second wavelength different from the first wavelength A non-polarization beam splitter which is coated on one side with a second light source and a dichroic mirror which passes or reflects the incident beam according to the wavelength of the incident beam, and transmits a predetermined amount of light of the incident beam and reflects the rest; A focusing unit for condensing the light beam passing through the polarization beam splitter on the corresponding surface of the optical disk having different wavelengths, recording densities, thicknesses, and the like, and when the reflected light beam from the optical disk enters the non-polarization beam splitter through the focusing unit It is configured to include a light detector for detecting the reflected light beam in the polarizing beam splitter and converting it into an electrical signal.

According to another aspect of the present invention, there is provided an optical pickup apparatus for a heterogeneous optical disk, comprising: a first light source for emitting a beam of a first wavelength, a second light source for emitting a beam of a second wavelength different from the first wavelength, and one side A λ / 2 plate for changing the direction of linearly polarized light is attached, and the λ / 2 plate is coated with a dichroic mirror for passing or reflecting the incident beam according to the wavelength of the beam, and passing or passing the incident beam according to the polarization direction of the incident beam. A λ / 4 plate for separating the reflected polarized beam and converting the linearly polarized beam passing through the polarized beam splitter into a circularly polarized beam or a circularly polarized beam linearly polarized beam reflected from the information recording surface of the optical disk, and the λ / 4 A focusing unit for condensing the circularly polarized beam converted in the plate onto the corresponding surface of the optical disk having different wavelengths, recording densities, thicknesses, and the like, and the reflected light beam from the optical disk passes through the focusing unit and the λ / 4 plate When joined By detecting the reflected light beam of the light beam splitter can consists including an optical detector for converting into an electric signal.

1 is a block diagram of an optical pickup apparatus for a heterogeneous optical disk according to a first embodiment of the present invention.

2 is a block diagram of an optical pickup apparatus for a heterogeneous optical disk according to a second embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

11: first light source 12: second light source

13: non-polarization beam splitter (NPBS) 13a: non-polarization beam splitter

13b: dichroic mirror 14: collimator lens

15: objective lens 16: optical disk

16a: first information recording surface 16b: second information recording surface

17 sensor lens 18 light detector

23: polarizing beam splitter (PBS) 23a: polarizing beam splitting surface

23b: lambda / 2 plate 23c: dichroic mirror

25: λ / 4 plate

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example 1

1 is a block diagram showing the configuration of an optical pickup apparatus for heterogeneous optical disks according to a first embodiment of the present invention.

1 shows a first light source 11 for generating a CD-R light beam, a second light source 12 for generating a DVD light beam, and a dichroic mirror for transmitting or reflecting an incident beam according to the wavelength of the beam ( 13b) is coated on the surface where the light beam of the wavelength for CD-R generated from the first light source 11 is incident, and NPBS 13 which passes a predetermined amount of light of the incident beam and reflects the rest regardless of the wavelength or polarization direction. A collimator lens 14 for advancing the beam passing in parallel in a predetermined direction, an objective lens 15 for condensing the beam emitted in parallel from the collimator lens 14 at a point on the surface of the optical disk 16, and When the reflected light beam from the optical disk 16 is incident on the NPBS 13, the light detector 18 detects the beam reflected from the NPBS 13 and converts it into an electrical signal.

In this case, a sensor lens 17 is disposed between the NPBS 13 and the photo detector 18.

In addition, the dichroic mirror 13b is formed by dichroic coating on a surface on which the light beam of the CD-R wavelength of the NPBS 13 is incident.

Here, the dichroic mirror 13b of the NPBS 13 has a plurality of optical coatings as a layer to pass beams of a specific wavelength and reflect beams of a different wavelength.

At this time, the light beam of the wavelength for CD-R generated in the first light source 11 has an optical path incident on the non-polarization beam separation surface 13a through the dichroic mirror 13b of the NPBS 13, The light beam having the wavelength for DVD generated from the two light sources 12 is reflected on the non-polarization beam separating surface 13a of the NPBS 13 and is incident on the dichroic mirror 13b and then again on the dichroic mirror 13b. Since the light paths are reflected and incident on the non-polarization beam splitting surface 13a, light beams having different wavelengths from the first and second light sources 11 and 12 have one light path.

Therefore, CD-R / CD / DVD recording / playback compatibility with the same optical pickup apparatus becomes possible.

In addition, light beams having different wavelengths generated at the first and second light sources 11 and 12 are transmitted through the NPBS 13 and the objective lens 15 coated with the dichroic mirror 13b. Is focused on one side, and the aperture ratio adjusting means may be added to the objective lens 15 for CD / DVD playback compatibility.

In this case, since the opening ratio adjusting means may be any method conventionally proposed, illustration and description are omitted.

At this time, the first information recording surface 16a of the optical disc 16 is the information recording surface of the DVD, the second information recording surface 16b is the information recording surface of the CD, and the second information recording surface 16b is the first information recording surface 16a. ) 0.6 mm away from the surface of the optical disk 16.

On the other hand, after focusing on the first information recording surface 16a or the second information recording surface 16b of the optical disk 16, the reflected beam is incident again to the NPBS 13 through the opposite path, and the NPBS 13 ), The light beam reflected by the light incident on the photodetector 18 passes through the sensor lens 17.

In this case, the NPBS 13, the collimator lens 14, the objective lens 15, the sensor lens 17 and the like are configured so that there is no chromatic aberration for each wavelength.

In the first embodiment of the present invention configured as described above, the wavelength of the light beam generated by the first light source 11 is 780 nm used for the CD-based optical disc, and the wavelength of the light beam generated by the second light source 12 is DVD-based. It is assumed that it is 635 to 650 nm used for the optical disk in

The dichroic mirror 13b that transmits or reflects the beam according to the wavelength is formed by dichroic coating on the surface where the beam of the CD-R wavelength of the NPBS 13 is incident. 13b) is assumed to be coated to transmit light at 780 nm wavelength and reflect light at 635-650 nm wavelength.

Here, 780 nm is a wavelength for CD-R, and 635-650 nm is a wavelength for DVD.

At this time, the CD can be read in both 780nm or 635 ~ 650nm, but in the present invention 780nm is used for the CD-R / CD / DVD combined use.

That is, the light beam of 780 nm wavelength generated from the first light source 11 is first incident on the dichroic mirror 13b of the NPBS 13, and the light beam of 780 nm wavelength is generated by the coating characteristic of the dichroic mirror 13b. All of them are transmitted and are incident on the non-polarization beam separation surface 13a of the NPBS 13.

The non-polarization beam splitting surface 13a transmits only a predetermined amount of the light beam passing through the dichroic mirror 13b regardless of the wavelength or polarization direction of the beam passing through the dichroic mirror 13b so that the collimator lens ( 14) and reflect the rest.

In addition, a light beam having a wavelength of 635 to 650 nm generated by the second light source 12 is first incident on the non-polarization beam separating surface 13a of the NPBS 13.

The non-polarization beam splitting surface 13a of the NPBS 13 reflects only a certain amount of light of a light beam having a wavelength of 635 to 650 nm to the dichroic mirror 13b and transmits the rest.

At this time, since the beam incident on the dichroic mirror 13b has a wavelength of 635 to 650 nm, it is reflected back by the dichroic coating characteristic and is incident on the non-polarization beam separation surface 13a of the NPBS 13.

The non-polarization beam splitting surface 13a transmits only a predetermined amount of the light beam reflected from the dichroic mirror 13b regardless of the wavelength of the beam reflected from the dichroic mirror 13b or the polarization direction, thereby allowing a collimator lens ( 14) and reflect the rest.

That is, the NPBS 14 has a property of reflecting 50% unconditionally and transmitting the remaining 50% irrespective of the property of the beam incident by the coating property of the non-polarization beam splitting surface 13a.

The collimator lens 14 advances the beam passing through the NPBS 13 in parallel to the objective lens 15, and the objective lens 15 is connected to the numerical aperture controlled by the numerical aperture adjusting device (not shown). Accordingly, the incident light beam is focused on the first information recording surface 16a or the second information recording surface 16b of the optical disk 16.

On the other hand, the light beam reflected from the first information recording surface 16a or the second information recording surface 16b passes through the objective lens 15 and the collimator lens 14 to the non-polarization beam separation surface 13a of the NPBS 13. Incident.

At this time, the non-polarization beam separation surface 13a of the NPBS 13 transmits a predetermined amount of the reflected light beam to the dichroic mirror 13b and reflects the rest to the sensor lens 17.

The sensor lens 17 corrects spherical aberration of the beam reflected from the NPBS 13 and focuses the light on the surface of the photodetector 18.

The photo detector 18 converts the incident light beam into an electrical signal to obtain a high frequency signal, a focus error signal, and a tracking error signal.

As such, the NPBS 13 has a beam path that reflects a predetermined amount of light to the photo detector 18 regardless of the wavelength or polarization direction of the light beam reflected from the optical disk 16. You do not have to do.

In addition, since dichroic coating is applied to one side of the NPBS 13 (for example, a surface into which a light beam having a wavelength for CD-R is incident), all four surfaces of the NPBS 13 can be used, so that a separate beam separation prism This eliminates the size of the optical pickup device and makes efficient use of space.

In this case, since the NPBS 13 transmits only 50% of the light incident to the incident beam and reflects the remaining 50%, the wavelength of the CD-R generated by the first light source 11 in the first embodiment is increased. When the beam passes through the NPBS 13, only 50% of the beam is directed to the optical disk 16, and only 50% of the beam reflected from the optical disk 16 enters the optical detector 18 through the NPBS 13 again. do.

This means that only 50% of the beams generated by the first light source 11 are incident on the optical disk 160 and only 25% are detected by the photodetector 18.

In addition, when the beam of the wavelength for DVD generated from the second light source 12 passes through the non-polarization beam separation surface 13a of the NPBS 13, only 50% of the beam is reflected by the dichroic mirror 13b and dichroic When the beam reflected from the blade mirror 13b passes through the non-polarization beam splitting surface 13a, only 50% of the reflected beam is directed to the optical disk 16, and only 50% of the beam reflected from the optical disk 16 is again. It enters into the photodetector 18 via the non-polarization beam splitting surface 13a of the NPBS 13.

This means that only 25% of the beams generated by the first light source 11 are incident on the optical disk 16 and only 12.5% are detected by the light detector 18.

Therefore, if only the playback operation is performed in the CD-R / DVD or CD / DVD player, the amount of light is sufficient, but the recording operation may not be performed properly because the beam loss is large in the recording operation.

Therefore, it is necessary to increase the amount of light incident on the optical disk 16 by reducing the beam loss.

Example 2

FIG. 2 is a block diagram of the optical pickup apparatus for a heterogeneous optical disk according to the second embodiment of the present invention, in which PBS and λ / 4 plates are used instead of NPBS of FIG. 1, and λ / 2 plates are formed on one side of the PBS. And the dichroic mirror on this λ / 2 plate to reduce beam loss, it is possible to accurately perform recording / playback operation on a CD-R / DVD or CD-R / CD / DVD player. .

2 shows a first light source 21 for generating a CD-R light beam, a second light source 22 for generating a DVD light beam, and a light beam having a wavelength for CD-R generated by the first light source 21. The λ / 2 plate 23b for changing the direction of linear polarization is attached to the incident surface, and the dichroic mirror 23c for transmitting or reflecting the incident beam to the λ / 2 plate 23b according to the wavelength of the beam. Is coated, from the collimator lens 24 and the collimator lens 24 for advancing or passing the beam passing through the PBS 23 in parallel in a predetermined direction, passing through or reflecting the incident beam according to the polarization direction. Λ / 4 plate 25 for converting the linearly polarized beams emitted in parallel into circularly polarized beams, an objective lens 26 for condensing the circularly polarized beams converted at λ / 4 on a surface of the optical disk 27, And when the reflected light beam from the optical disk 27 enters the PBS 23 through the objective lens 26, the λ / 4 plate 25, and the collimator lens 24, Detecting the beam which is reflected is composed of the photodetector 29 for conversion into an electric signal.

In this case, a sensor lens 28 is disposed between the PBS 23 and the photo detector 29.

In addition, the dichroic mirror 23c is formed by dichroic coating on a surface on which the light beam of the CD-R wavelength of the PBS 23 is incident.

Here, the dichroic mirror 23c coated on one side of the PBS 23 is a layer of several optical coatings, and has a property of passing a beam of a specific wavelength and reflecting a beam of a different wavelength.

At this time, the light beam of the wavelength for the CD-R generated from the first light source 21 first passes through the dichroic mirror 23c of the PBS 23 and the λ / 2 plate 23b to the polarization beam separation surface 23a. The light beam having the incident light path and the wavelength for DVD generated from the second light source 22 is first reflected by the polarization beam splitting surface 23a of the PBS 23 and incident on the λ / 2 plate 23b, and then Since the polarization direction is converted in the / 2 plate 23b and then is reflected by the dichroic mirror 23c to have an optical path incident on the polarization beam splitting surface 23a, the first and second light sources 21, The light beams of different wavelengths from 22 have one light path.

Therefore, CD-R / CD / DVD recording / playback compatibility with the same optical pickup apparatus becomes possible. The light beams having different wavelengths generated by the first and second light sources 21 and 22 are the PBS 23 and the objective lens 26 having the dichroic mirror 23c and the λ / 2 plate 23b. By condensing on one surface of the optical disk 27, the aperture ratio adjusting means may be added to the objective lens 26 for CD / DVD playback compatibility.

In this case, since the opening ratio adjusting means may be any method conventionally proposed, illustration and description are omitted.

At this time, the first information recording surface 27a of the optical disk 27 is the information recording surface of the DVD, the second information recording surface 27b is the information recording surface of the CD, and the second information recording surface 27b is the first information recording surface 27a. ) 0.6 mm away from the surface of the optical disk 27.

On the other hand, the beam reflected after focusing on the first information recording surface 27a or the second information recording surface 27b of the optical disk 27 is incident to the PBS 23 through the opposite path again. The reflected light beam is incident on the photo detector 29 via the sensor lens 28.

In the second embodiment of the present invention configured as described above, the wavelength of the light beam generated by the first light source 21 is 780 nm used for the CD-based optical disk, and the wavelength of the light beam generated by the second light source 22 is DVD-based. It is assumed that it is 635 to 650 nm used for the optical disk in

In addition, linearly polarized light of beams having different wavelengths emitted from the first and second light sources 21 and 22 is fixed to S waves, and the polarization beam separation surface 23a of the PBS 23 transmits P waves and S waves Suppose it reflects.

In addition, a dichroic mirror 23c is coated on one side of the PBS 23 (for example, a surface on which a light beam of a wavelength for CD-R is incident) to transmit or reflect the beam according to the wavelength. (23c) is assumed to be coated to transmit light at 780 nm wavelength and reflect light at 635 to 650 nm wavelength.

Here, 780 nm is a wavelength for CD-R, and 635-650 nm is a wavelength for DVD.

At this time, the CD can be read in both 780nm or 635 ~ 650nm, but in the present invention 780nm is used for the CD-R / CD / DVD combined use.

That is, when a linearly polarized beam of S-wave having a wavelength of 780 nm is generated from the first light source 21 and is incident on the dichroic mirror 23c of the PBS 23, all of them are transmitted by the dichroic coating characteristic and are λ / 2 plates. It enters into 23b.

In this case, since the λ / 2 plate 23b converts the direction of linear polarization, that is, the S wave is a P wave, and the P wave is a polarization converting plate which converts the S wave, the S wave having a 780 nm wavelength passing through the dichroic mirror 23 c is It is converted into a P wave and is incident on the polarization beam splitting surface 23a of the PBS 23.

Since the polarization direction of the 780 nm wavelength incident on the polarizing beam splitting surface 23a of the PBS 23 is P wave, the P wave passes through the polarizing beam splitting surface 23a of the PBS 23 as it is and the collimator lens 24 is used. Is incident to and focused on parallel light.

Further, the linearly polarized beam of S-wave having a wavelength of 635 to 650 nm generated from the second light source 22 directly enters the polarization beam splitting surface 23a of the PBS 23.

At this time, the beam incident on the polarization beam splitting surface 23a of the PBS 23 is S-wave, so it is reflected and incident on the λ / 2 plate 23b. The λ / 2 plate 23b converts the S-wave into a P wave. Convert.

The beam of wavelength 635 to 650 nm converted into P wave in the λ / 2 plate 23b is all reflected by the dichroic coating characteristic in the dichroic mirror 23c and is incident again to the polarization beam splitting surface 23a.

Since the polarization direction of 635 to 650 nm wavelength incident on the polarizing beam splitting surface 23a of the PBS 23 is P wave, the P wave passes through the polarizing beam splitting surface 23a of the PBS 23 as it is and is a collimator lens ( Incident to 24) and connected in parallel light.

Then, the linearly polarized beam of P-wave connected to parallel light through the collimator lens 24 is incident on the λ / 4 plate 25 which is a polarization converter.

At this time, when the P-wave, which is a linearly polarized beam, passes through the λ / 4 plate 25, it is converted into a right-turning circularly polarized beam.

Then, the right-turning circularly polarized beam is incident on the objective lens 26, and the objective lens 26 is the first information recording surface of the optical disk 27 in accordance with the numerical aperture adjusted by the numerical aperture adjusting device (not shown). The incident light beam is focused on the 27a or the second information recording surface 27b.

On the other hand, the light beam reflected from the first information recording surface 27a or the second information recording surface 27b is incident on the λ / 4 plate 25 via the objective lens 26.

At this time, when the right rotating circularly polarized beam is reflected from the first information recording surface 27a or the second information recording surface 27b, it is diffracted by the information carrier on the information recording surface and converted into a left rotating circularly polarized beam. Passing through the [lambda] / 4 plate 25 converts it into an S wave which is a linearly polarized beam.

The S-wave converted by the λ / 4 plate 25 is incident to the polarization beam splitting surface 23a of the PBS 23 via the collimator lens 24, and the polarization beam splitting surface 23a of the PBS 23 is Reflects all incident S waves.

The S-waves reflected from the PBS 23 are incident toward the sensor lens 28, and the sensor lens 28 concentrates the surface of the photo detector 29 after correcting spherical aberration of the reflected beam.

The photo detector 29 converts the incident light beam into an electrical signal to obtain a high frequency signal, a focus error signal, and a tracking error signal.

As described above, the second embodiment of the present invention uses PBS instead of NPBS, attaches a λ / 2 plate to one side of the PBS, and coats the dichroic mirror on the λ / 2 plate. By arranging the λ / 4 plate at the same time, and matching the linear polarization directions of the beams generated from the second and second light sources, space utilization can be efficiently performed by using all four surfaces of the PBS, and the first or second information recording surface of the optical disc Since the reflected light beam from the information recording surface has a beam path reflected by the λ / 4 plate and PBS to the photodetector, it is not necessary to configure separate photodetectors for the two wavelengths.

In addition, by using PBS, λ / 2 plate, and λ / 4 plate instead of NPBS, the amount of light emitted from the first and second light sources is passed or reflected in the PBS without loss, thereby recording the CD-R or DVD. Sufficient light efficiency can be obtained that can be used.

As described above, according to the optical pickup device for heterogeneous optical disks according to the present invention, NPBS having a dichroic-coated NPBS having a light source having different wavelengths and having one side, that is, a surface on which the wavelength for CD-R is incident By using, the reflected light beams from optical disks having different wavelengths and thicknesses can be detected using one optical detector, and playback compatibility of optical disks having different wavelengths and thicknesses is made possible.

In addition, a PBS having a separate light source having a different wavelength and having a λ / 2 plate attached to one side, that is, a side to which a beam having a wavelength for CD-R is incident, is coated with a dichroic mirror on the λ / 2 plate. Thus, the reflected light beams from the optical disks having different wavelengths and thicknesses can be detected by using one optical detector, and since no optical loss occurs, recording / playback compatibility of optical disks having different wavelengths and thicknesses is made possible. .

In addition, the λ / 2 plate is attached to the surface where the beam of the wavelength of the CD-R is incident on the surface where the beam of the wavelength of the CD-R is incident or the dichroic mirror is attached to the λ / 2 plate. By using the coated PBS, since all four sides of the NPBS or PBS is used, space utilization can be efficiently made, and the optical pickup device can be made compact.

As a result, the optical detector and the use of NPBS or PBS maximize the space utilization, thereby making the volume of the optical pickup device small and simple, making it easy to reduce the thickness of the optical pickup device, lowering the price, and having different wavelengths and thicknesses. Disc recording / playback is compatible.

Claims (23)

First light emitting means for emitting a beam of a first wavelength, second light emitting means for emitting a beam of a second wavelength different from the first wavelength, and beam separation for passing or reflecting an incident beam according to the wavelength of the incident beam The non-polarization beam separation means which transmits a predetermined amount of light of the incident beam and is coated on one side of the article and reflects the rest of the light beam, and the optical beam passing through the non-polarization beam separation means are different in wavelength, recording density, thickness, etc. Focusing means for condensing on the surface, and optical detection means for detecting the reflected light beam from the non-polarization beam separation means and converting the reflected light beam from the optical disk into the non-polarization beam separation means through the focusing means and converting it into an electrical signal. Optical pickup device for heterogeneous optical disk, characterized in that comprises a. 2. The heterogeneous optical disc according to claim 1, wherein the first and second light emitting means emit a beam having a wavelength used for the CD optical disc and a beam having a wavelength used for the DVD optical disc. Optical pickup. The optical pickup apparatus for a heterogeneous optical disc according to claim 1, wherein the first and second light emitting means emit light beams having a wavelength of 780 nm and beams having a wavelength of 635 to 650 nm, respectively. The optical pickup apparatus of claim 1, wherein the beam splitter of the non-polarization beam splitter is a dichroic mirror. The optical pickup apparatus of claim 1, wherein the non-polarization beam separation means is made by dichroic coating on a surface on which a beam of a wavelength used in a CD-based optical disk is incident. The non-polarization beam separation means according to claim 1, wherein a beam having a wavelength used for a CD-based optical disk first passes through a beam separator and then enters a non-polarization beam separation surface, and only a predetermined amount of light of the incident beam is non-polarized. An optical pickup apparatus for heterogeneous optical disks, characterized in that the optical path passes through the beam separation surface and enters the optical path incident to the focusing means. The non-polarization beam separation surface according to claim 1, wherein the non-polarization beam separation means has a beam of a wavelength used for a DVD-based optical disk first being incident on the non-polarization beam separation surface, and only a predetermined amount of incident light is reflected by the beam separator. The optical pickup apparatus for heterogeneous optical disks, characterized in that the light beam is incident to the light path passing through the non-polarization beam separation plane and incident to the focusing means. The optical pickup apparatus for a heterogeneous optical disc according to claim 1, wherein the focusing means is provided with an aperture ratio adjusting means. The optical sensor of claim 1, wherein the light detector comprises: a sensor lens for correcting spherical aberration of the light beam reflected from the non-polarization beam splitter; and a light for detecting and converting a light beam whose spherical aberration is corrected from the sensor lens into an electrical signal. Optical pickup device for heterogeneous optical disk, characterized in that consisting of a detector. 2. The heterogeneous optical disk according to claim 1, wherein a collimator lens is installed between the non-polarization beam separation means and the objective lens of the focusing means so that the light beam passing through the non-polarization beam separation means proceeds in parallel to the objective lens. Optical pickup device. First light emitting means for emitting a beam of a first wavelength; Second light emitting means for emitting a beam of a second wavelength different from the first wavelength; A first polarization transducer for changing the direction of linearly polarized light is attached to one side, and the first polarization transducer is coated with a beam splitter for passing or reflecting the incident beam according to the wavelength of the beam. Polarizing beam separating means for passing or reflecting; A second polarization converter for converting the linearly polarized beam passing through the polarization beam splitting means into a circularly polarized light beam or converting the circularly polarized beam reflected from the information recording surface of the optical disk into a linearly polarized beam; Focusing means for condensing the circularly polarized beam converted by the second polarization converter on a corresponding surface of an optical disk having a different wavelength, recording density, thickness, and the like; And a light detecting means for detecting the reflected light beam from the polarizing beam separating means and converting the reflected light beam from the optical disk into the polarizing beam separating means through the focusing means and the second polarization converter. Optical pickup device for heterogeneous optical disk. 12. The heterogeneous optical disc according to claim 11, wherein the first and second light emitting means emit a beam of a wavelength used for the CD-based optical disc and a beam of a wavelength used for the DVD-based optical disc, respectively. Optical pickup. 12. The optical pickup apparatus for heterogeneous optical disks according to claim 11, wherein the first and second light emitting means emit light beams having a wavelength of 780 nm and beams having a wavelength of 635 to 650 nm, respectively. 12. The optical pickup apparatus of claim 11, wherein the beam splitter of the polarizing beam splitting means is a dichroic mirror. The optical pickup apparatus for heterogeneous optical disks according to claim 11, wherein the polarization beam separation means is formed by dichroic coating on a surface on which a beam having a wavelength used for a CD-based optical disk is incident. 12. The optical pickup apparatus of claim 11, wherein the first polarization converter of the polarization beam splitting means is a λ / 2 plate. 12. The method of claim 11, wherein the polarization beam separation means is a beam of the wavelength used for the CD-based optical disk first passes through the first polarization transducer when the incident to the beam splitter, the first polarization transducer converts the direction of polarization The optical pickup apparatus for heterogeneous optical disks, characterized in that the light beam is converted into a light path that is incident to the focusing means. 18. The optical pickup apparatus for heterogeneous optical disks according to claim 17, wherein the beam having a wavelength used for the CD-based optical disk incident to the beam splitter is S-wave. The method according to claim 11, wherein the polarization beam separation means reflects the incident beam to the first polarization transducer when a beam of wavelength used for the DVD-based optical disk is incident, and beams the beam whose polarization direction is converted in the first polarization transducer. And entering the separator, and when the incident beam is reflected by the beam separator, the reflected beam proceeds in the optical path incident on the focusing means as it is. 12. The optical pickup apparatus of claim 11, wherein the second polarization converter is a λ / 4 plate. 12. The optical pickup apparatus for heterogeneous optical disks according to claim 11, wherein the focusing means is provided with an aperture ratio adjusting means. 12. The optical detector of claim 11, wherein the light detector comprises: a sensor lens for correcting spherical aberration of the light beam reflected from the polarization beam splitter; and a photo detector for detecting and converting a light beam whose spherical aberration is corrected from the sensor lens into an electrical signal. Optical pickup device for heterogeneous optical disk, characterized in that consisting of. 12. The heterogeneous optical disc according to claim 11, wherein a collimator lens is installed between the polarization beam separation means and the second polarization converter to allow the light beam passing through the polarization beam separation means to travel in parallel to the second polarization converter. Optical pickup.