KR19980072248A - Optical pickup device for different optical discs - Google Patents

Abstract

The present invention relates to an optical pickup device for heterogeneous optical disks having different substrate thicknesses and wavelengths, and in particular, by separately configuring a plurality of light sources generating different wavelengths and transmitting or reflecting beams according to the wavelengths generated by the plurality of light sources. CD / DVD-based optical discs with different wavelengths can be recorded and played back, and the numerical aperture of the objective lens can be selectively transmitted through all or part of the beam depending on the wavelength of the transmitted or reflected beam. It is easy to adjust the numerical aperture without the need for a separate component, making it easy to reduce the thickness of the optical pickup device and to record / play back compatible CD / DVD-based optical discs having different thicknesses and recording densities. Become.

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 and digital video discs 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.

That is, in the case of CD-R, the medium of the disc uses a cyanine (blue pigment) dye, which has a property of having a reflectance only at 780 nm as shown in FIG.

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, a CD-R light source and a DVD light source are required to use the CD-R as a combined use. Therefore, a method of configuring two light sources in the same laser diode package and using the same pickup is proposed.

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

In addition, in order to read a CD or CD-R in a DVD player, it is necessary to adjust the numerical aperture (NA) of the objective lens.

That is, in the case of the combined CD / DVD, a light source having the same wavelength may be used, but since the thickness of the disk is different (for example, 1.2 μm for a CD and 0.6 μm for a DVD), spherical aberration is changed, and it is necessary to correct this.

For example, in the case of CD, the aperture ratio NA1 of the objective lens required should be smaller than the required aperture ratio NA2 in the case of DVD (NA2 NA1).

Accordingly, in order to control such aperture ratio, a liquid crystal shutter system for converting polarization directions according to power on / off, and a twin-lens system for mounting a DVD objective lens and a CD objective lens in one actuator are conventionally used. Several methods have been proposed.

However, the liquid crystal shutter method or the twin lens method requires a separate optical device to be added, resulting in heavy and complicated products, making it difficult to light and short and increase in price.

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 wavelengths, thereby making recording / playback compatible with optical discs having different wavelengths. There is provided an optical pickup device for heterogeneous optical disks to enable this.

Another object of the present invention is to selectively transmit all or a part of the beam according to the wavelength, thereby making it easy to adjust the aperture ratio of the objective lens to enable recording / playback compatibility of optical discs having different thicknesses and recording densities. An optical pickup device is provided.

A feature of the optical pickup device for heterogeneous optical disks according to the present invention for achieving the above object is a first light source for emitting a beam of a first wavelength, and a beam of a second wavelength different from the first wavelength A beam splitter for transmitting or reflecting the incident beam according to the second light source, the wavelength of the beam emitted from the first or second light source, and all or part of the incident beam according to the wavelength of the beam transmitted or reflected by the beam splitter. A light blocking portion for selectively passing through, a focusing portion for condensing a light beam on a corresponding surface of an optical disk having a different wavelength, recording density and thickness by maintaining a different numerical aperture according to the amount of light passing through the light blocking portion, and from the heterogeneous optical disk. And a first light detector and a second light detector for detecting the reflected light beams sequentially through the focusing unit, the light shielding unit, and the beam splitter, respectively.

Other features of the optical pickup apparatus for heterogeneous optical disks according to the present invention include 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 the first light source. 1, a beam splitter for transmitting or reflecting the incident beam according to the wavelength of the beam emitted from the second light source, and for adjusting the effective numerical aperture of the objective lens in order to reduce aberration caused by the difference in thickness of the disk in a part of the lens A focusing unit configured to selectively pass a part or all of the beams transmitted or reflected by the beam splitter to condense the light beams on the surfaces of different types of optical discs, and the reflected light beams from the heterogeneous optical discs; The first and second photodetectors for sequentially detecting the focusing unit and the beam splitter, respectively, are included.

Another feature of the optical pickup device for heterogeneous optical disks according to the present invention is that the first light source emits a beam of wavelengths used for the CD-based optical disc, and the beam of wavelengths used for the DVD-based optical disc. A collimator lens for advancing the beam of the wavelength generated by the first light source in parallel in a predetermined direction, a correcting lens for correcting the aberration of the beam generated from the second light source, and the collimator lens or the correcting lens A beam splitter that transmits or reflects an incident beam according to the wavelength of the beam passing through, a light shield that selectively passes all or a portion of the incident beam according to the wavelength of the beam transmitted or reflected by the beam splitter, and passes the light shield Focusing unit for focusing the light beam on the surface of the optical disk having different wavelengths, recording densities and thicknesses by maintaining different numerical apertures according to the amount of light And there consists.

Another feature of the optical pickup apparatus for heterogeneous optical disks according to the present invention is that the first light source emits a beam of a wavelength used for a DVD-based optical disk, and the beam of a wavelength used for the CD-based optical disk is emitted. A second light source, a beam splitter for transmitting or reflecting an incident beam according to a wavelength of a beam generated from the first or second light source, and a collimator lens for advancing light reflected or transmitted by the beam splitter in parallel in a predetermined direction And a light shielding portion for selectively passing all or a portion of the incident beam incident through the collimator according to the wavelength of the beam, and a different numerical aperture according to the amount of light passing through the light blocking portion to maintain the wavelength, recording density and thickness. And a focusing portion for focusing light beams on corresponding surfaces of different optical disks.

1 is a graph showing reflection characteristics of a typical CD-R disc medium.

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

FIG. 3 is a view illustrating a relationship between an optically coated region and an uncoated region formed in the objective lens of FIG.

4 is a graph showing coating characteristics applied to the optical coating region of FIG.

FIG. 5 is a cross-sectional view illustrating the light condensing on a CD-based optical disk by blocking a beam of a specific wavelength in FIG. 3 in an optical coating region. FIG.

FIG. 6 is a cross-sectional view of an incident beam irrespective of the wavelength of FIG. 3 condensing the beam onto a DVD-based optical disc by passing through the optically coated and uncoated regions unconditionally.

FIG. 7 is a cross-sectional view illustrating an example in which the optically coated and uncoated regions of FIG. 3 are formed on separate glass substrates.

FIG. 8 is a cross-sectional view illustrating the integration of a photo detector into a light source package in FIG.

Fig. 9 is a block diagram showing an embodiment in which the objective lens optical coating of the present invention is applied to a DVD infinity / CD finite optical pickup apparatus.

FIG. 10 is a block diagram showing an embodiment in which the objective optical coating of the present invention is applied to a DVD infinity / CD infinity optical pickup device. FIG.

Explanation of symbols for the main parts of the drawings

21: first light source 22: second light source

23 beam splitter 24 objective lens

24a: first side 24b: second side

24c: uncoated area 24d: optical coating area

25 optical disc 25a first information recording surface

25b: second information recording surface 26: collimator lens

27: half mirror 28: photo detector

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

2 is a block diagram of an optical pickup device for heterogeneous optical disks according to the present invention, wherein a first light source 21 for generating a light beam for CD-R, a second light source 22 for generating a light beam for DVD, and the first A beam splitter 23 for transmitting or reflecting the light beams generated according to the wavelengths generated by the second light sources 21 and 22, and an optical disc by adjusting the aperture ratio according to the wavelength transmitted or reflected by the beam splitter 23. It consists of the objective lens 24 which condenses on one point on the surface of (25).

At this time, between the second light source 22 and the beam splitter 23, a half mirror 27 and the beam splitter (reflecting the beam generated by the second light source 22 to the beam splitter 23) A collimator lens 26 is provided for making the beam reflected by 24 into parallel light.

In addition, a photo detector 28 is provided that detects through the half mirror 27 when a beam traveling in parallel through the collimator lens 26 is reflected off the disk and returned.

The beam separator 23 is formed by bonding two glass substrates and dichroic coating on the bonding surface.

In this case, the dichroic coating surface has a property of passing a beam of a specific wavelength and reflecting a beam of a different wavelength as a layer of several optical coatings.

Therefore, when incident beams of different wavelengths are incident through different surfaces of the beam splitter 23, the beams of one wavelength are transmitted and the beams of the other wavelengths are incident on the dichroic coating surface such that the beams are reflected. The beams passing or reflecting through the separator 23 have optical systems having the same paths as each other.

Therefore, CD-R / DVD playback compatibility can be achieved by using the same optical pickup device.

The beam that transmits or reflects the beam splitter 23 is focused on one surface of the optical disk 25 through the objective lens 24, and the aperture ratio is required for CD / DVD playback compatibility.

In this case, since beams having different wavelengths are incident on the CD and the DVD, the size of the incident mirror is adjusted using this difference.

That is, by forming an optical coating film for blocking a specific wavelength, for example, the wavelength for CD, in the remaining region except for the portion corresponding to the opening ratio (NA) for the CD, the wavelength for the DVD is transmitted as it is and the wavelength for the CD is incident by the optical coating film. Since the diameter of the mirror is adjusted, the incident light is not large, and spherical aberration is not large.

In an embodiment of the invention the optical coating is a dichroic coating.

That is, when the CD series uses a wavelength of 780 nm, the DVD series uses a wavelength of 635-650 nm, the NA required for the CD series is NA1 = 0.45, and the NA required for the DVD series is NA2 = 0.6.

At this time, when the focal length is F, the incident light of the CD series requires D1 = 2 · NA1 · F, the incident light of the DVD requires D2 = 2 · NA2 · F, and becomes D2 D1.

Accordingly, as shown in FIG. 3, the dichroic film reflecting the CD wavelength beam is not transmitted but is coated on the region 24d except for the incident diameter D1 corresponding to the case where the CD NA is 0.45.

4 is a graph showing the characteristics of the optical coating film applied to the optical coating region 24a, and shows reflection at 780 nm, which is the wavelength of the CD.

Accordingly, the wavelength for the CD passes through only the uncoated region 24c in the center portion as shown in FIG. 5, and the wavelength for the DVD passes through both the uncoated region 24c and the optical coating region 24d as shown in FIG. 6. You can play both CD and DVD using the objective lens.

However, in the non-coated area 24c and the optical coating area 24d, a path difference due to the thin film thickness may occur, which may distort the beam spot. After passing through the blade film, the phase difference between the uncoated region 24c and the light passing through the optical coating region 24d is adjusted to be? / 10 or less.

In this case, the optical coating film may be formed on the first surface 24a or the second surface 24b of the objective lens 24 as shown in FIG. 2, or may be optically formed on a separate optical glass plate 31 as shown in FIG. 7. After the coating film 31a is formed, it may be installed on the front surface of the objective lens 32.

2, the first information recording surface 25a of the optical disk 25 is an information recording surface of a DVD, the second information recording surface 25b is an information recording surface of a CD, and the second information recording surface 25b is a first information. It is located 0.6 mm further from the surface of the optical disk 25 than the recording surface 25a.

On the other hand, the beam reflected after the focus on the first information recording surface 25a or the second information recording surface 25b of the optical disk 25 is incident to the beam splitter 23 again through the opposite path, and again, the wavelength The beam splitter 23 is then transmitted or reflected to be incident on each photodetector.

At this time, the photo detector may be configured integrally with the light source, or may be configured separately.

In the embodiment of the present invention, the light detector for detecting the beam passing through the beam splitter 23 is integrated into the first light source 21 package as shown in FIG. 8, and the beam detector 23 detects the beam reflected from the beam splitter 23. The photodetector 28 is installed on the path of the collimator lens 26, which serves to advance the beam into parallel light, and the half mirror 27 reflecting the beam emitted from the second light source 22, wherein the photodetector 28 is provided separately from the second light source 22.

As such, the photodetectors may both be of an integral type, both of them may be of a separate type, and may be of an integral type and of a separate type.

In the case of an integrated structure, as shown in FIG. 8, the laser diode 41 and the photo detector 42 are arranged side by side in the package of the light source, and the beam incident into the light source package using the hologram 43 is used to detect the beam 42. Diffract

The present invention configured as described above will be described with reference to FIG. 2.

In this case, it is assumed that the wavelength of the light beam generated by the first light source 21 is 780 nm, and the wavelength of the light beam generated by the second light source 22 is 635-650 nm, and the CD light detector is a package of the first light source 21. It is assumed that the light detector 28 for DVD is configured separately.

Here, since the objective lens 24 needs to be corrected for a DVD having a large numerical aperture NA, the aberration is corrected for a wavelength of 635 nm to 650 nm, and thus the wavelength is different when the CD or CD-R is reproduced. Therefore, a correction lens is needed to correct chromatic aberration caused by this.

However, in the case of not using such a correction lens, it is necessary to adjust the magnification by adjusting the distance between the laser diode and the disk.

In addition, the junction surface of the beam splitter 23 has a dichroic coating that transmits or reflects a beam according to the wavelength. The dichroic coating surface transmits light of 780 nm wavelength and reflects light of 635-650 nm wavelength. Assume that it is dichroic coated.

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 combined.

Hereinafter, the case of recording and reproducing a CD-based optical disc and the case of recording and reproducing a DVD-based optical disc will be described separately.

i) CD series optical disc

When a light beam having a wavelength of 780 nm generated by the first light source 21 is incident on the beam separator 23, it is transmitted by the coating property of the dichroic coating surface and is incident on the objective lens 24.

In this case, as shown in FIG. 3, the first surface 24a of the objective lens 24 reflects the uncoated region 24c that transmits both the wavelength for the CD and the wavelength for the DVD and the wavelength for the CD, and transmits only the wavelength for the DVD. The optical coating area 24d is formed, and the dichroic coating film for reflecting or transmitting the incident beam according to the wavelength is formed as shown in FIG. 4.

Therefore, the beam for CD transmitted through the beam separator 23 and incident on the objective lens 24 is transmitted in the uncoated region 24c and reflected in the optical coating region 24d, as shown in FIG. Is reduced.

When the beam diameter of the light beam is reduced, the objective lens 24 reduces the numerical aperture to the CD numerical aperture (i.e., 0.45) so that the optical beam passing through the uncoated region 24c can receive the second information recording surface 25b of the optical disk 25. In other words, the information is recorded on the information recording surface of the CD accurately so that the information is recorded on the CD or the recorded information is accessed.

On the other hand, the light beam reflected from the second information recording surface 25b is incident to the beam separator 23 through the objective lens 24.

Since the wavelength of the light beam incident from the objective lens 24 to the beam separator 23 is also 780 nm, the light is transmitted through the light source 21 after being transmitted.

In this case, as shown in FIG. 8, a laser diode 41 is disposed in parallel with the photodetector 42, and the beam incident on the light source 21 is diffracted by the hologram 43 to emit light. Incident to the detector 42.

The photo detector 42 converts the incident light beam into an electrical signal to obtain a high frequency signal, a focus error signal, and a tracking error signal.

ii) DVD series optical disc

When a light beam having a wavelength of 635-650 nm generated by the second light source 22 is reflected by the half mirror 27 and then enters the beam separator 23 through the collimator lens 26, the coating characteristic of the dichroic coating surface is applied. The light is reflected by the light and enters the objective lens 24.

In this case, as shown in FIG. 3, the first surface 24a of the objective lens 24 reflects the uncoated region 24c that transmits both the wavelength for the CD and the wavelength for the DVD and the wavelength for the CD, and transmits only the wavelength for the DVD. Since the light beam reflected by the beam splitter 23 is incident, the uncoated area 24c and the optical coating area 24d of the first surface 24a of the objective lens 24 are formed. Is transmitted as shown in FIG.

Therefore, since the beam diameter of the light beam is not reduced, the objective lens 24 maintains the original numerical aperture (i.e., 0.6).

Therefore, the objective lens 24 transmits a light beam passing through both the uncoated region 24c and the optical coating region 24d by moving a movie of an actuator provided with the objective lens 24. The information is recorded on the information recording surface 25a, i.e., the information recording surface of the DVD, so that the information can be recorded on the DVD or the recorded information can be accessed.

On the other hand, the light beam reflected from the first information recording surface 25a is incident to the beam separator 23 through the objective lens 24.

Since the wavelength of the light beam incident from the objective lens 24 to the beam separator 23 is also 635-650 nm, the beam splitter 23 reflects the incident light and enters the collimator lens 26.

At this time, since it is assumed that the aberration of the objective lens is aligned with the DVD, the reflected beam is focused again by the collimator lens 26 and is incident on the half mirror 27.

The half mirror 270 transmits a part of the focused beam toward the photo detector 28.

The photo detector 28 converts the incident light beam into an electrical signal to obtain a high frequency signal, a focus error signal, and a tracking error signal.

In the present invention, the uncoated region 24c of the objective lens 24 may have an optical coating for transmitting all wavelengths, and the optical coating region 24d may have an optical coating for reflecting only a specific wavelength.

In addition, a separate optical glass plate 31 may be used as shown in FIG. 7 without integrating the optical coating of the objective lens 24 with the objective lens 24.

In addition, the characteristics of the coating film of the beam separator 23 and the coating film of the objective lens 24 may be the same or different depending on the configuration.

That is, when the two light sources are positioned opposite to FIG. 2, the characteristics of the coating film of the beam separator 23 and the coating film of the objective lens 24 are different.

In the present invention, instead of applying dichroic coating, by adding an annular band to the objective lens 24, both DVD and CD series can be reproduced.

Here, the position of the band is a numerical aperture near 0.45, i.e. the radius of the objective lens is a and the radius of the band is r.

In addition, the properties of the band may be such that the incident beam is blocked, or the phase of the incident beam may be changed 180 degrees.

Therefore, when the DVD-based wavelength is incident, all of them are transmitted. When the CD-based wavelength is incident, the band of the CD-based wavelength is separated into an effective part and a noise part.

In this case, rather than adjusting the incident diameter of the beam itself, the DVD and CD-based optical discs are reproduced by reducing the influence of the subbeam caused by the spherical aberration difference.

9 is another embodiment in which the objective lens optical coating according to the present invention is applied to a DVD infinity / CD finite system optical pickup apparatus, in which a laser diode and a light detector are integrated in the DVD light source 51 and the CD light source 52. The beam generated from the DVD light source 51 is incident on the collimator lens 52, and the collimator lens 53 advances the incident beam in parallel toward the beam separator 54.

In addition, the beam generated by the CD light source 52 is incident on the beam splitter 54 through the correction lens 58 for correcting the CD aberration.

The beam splitter 54 transmits or reflects an incident beam according to the wavelength of the beams generated by the light sources 51 and 52, and the beam transmitted or reflected is incident to the objective lens 56.

In this case, an optical glass plate 55 is disposed between the beam separator 54 and the objective lens 56, and an optical coating film for blocking the wavelength of the CD is disposed on the optical glass plate 55 corresponding to the opening ratio NA for the CD. It forms in the remaining regions except for the wavelength of DVD, and the wavelength of CD is reflected by the optical coating film.

Therefore, not only the DVD series recording / playback but also the CD series recording / playback are possible using one objective lens.

FIG. 10 shows another embodiment in which the objective optical coating according to the present invention is applied to a DVD infinity / CD infinity optical pickup device. The DVD light source 61 and the CD light source 62 include a laser diode and a light detector. It is integrally formed and the beams generated by the light sources 61 and 62 are incident on the beam splitter 63.

The beam splitter 63 transmits or reflects an incident beam according to the wavelength of the beams generated by the light sources 61 and 62, and the beam that is transmitted or reflected is incident to the collimator lens 65 via the mirror 64. .

The collimator lens 65 advances the incident beam in parallel toward the objective lens 66.

The objective lens 66 uses a lens whose aberration is corrected for both the CD and the DVD, and the optical coating film for blocking the wavelength of the CD on the first surface of the objective lens 66 except for the portion corresponding to the opening ratio (NA) for the CD. The wavelength for the DVD is transmitted as it is, and the wavelength for the CD is reflected by the optical coating film.

Alternatively, the annular band described above may be formed in the objective lens 66 so that the effective light portion and the noise light portion are separated when the light passing through the lens reads the CD.

Therefore, not only the DVD series recording / playback but also the CD series recording / playback are possible using one objective lens.

As described above, according to the optical pickup apparatus for a heterogeneous optical disk according to the present invention, a plurality of light sources generating different wavelengths are separately configured, and different wavelengths are transmitted by transmitting or reflecting beams according to the wavelengths generated by the light sources. Recording / playback compatibility of the CD-based optical disc / DVD-based optical disc used can be made.

In addition, by selectively transmitting the whole or part of the beam according to the wavelength of the transmitted or reflected beam to adjust the numerical aperture of the objective lens, it is easy to adjust the numerical aperture without the need for a separate component, making it easy to reduce the thickness of the optical pickup device In addition, recording / playback compatibility of CD-based optical discs / DVD-based optical discs having different thicknesses and recording densities becomes possible.

Claims (25)

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; Beam separation means for transmitting or reflecting the incident beam according to the wavelength of the beam generated by the first or second light emitting means; Light blocking means for selectively passing all or part of the incident beam according to the wavelength of the beam transmitted or reflected by the beam separation means; Focusing means for condensing a light beam on a corresponding surface of an optical disk having a different wavelength, recording density and thickness by maintaining a different numerical aperture in accordance with the amount of light passing through the light shielding means; And first and second optical detection means for detecting the reflected light beam from the heterogeneous optical disk sequentially through a focusing means, a light shielding means, and a beam separating means, respectively. The method of claim 1, wherein the first and second light emitting means An optical pickup apparatus for heterogeneous optical disks, characterized by emitting light beams of wavelengths used for CD-based optical disks and beams of wavelengths used for DVD-based optical disks. The method of claim 1, wherein the first and second light emitting means An optical pickup apparatus for heterogeneous optical discs, characterized in that it emits a beam of 780nm wavelength and a beam of 635-650nm wavelength, respectively. The method of claim 1, wherein the beam separation means An optical pickup apparatus for heterogeneous optical disks, wherein two glass substrates are bonded to each other and formed by dichroic coating on the bonding surface. The method of claim 1, wherein the light blocking means A specific wavelength is divided into a blocking region for blocking and a transmission region for transmitting an incident beam unconditionally regardless of the wavelength. 6. The optical pickup apparatus of claim 5, wherein a phase difference correction coating is formed in the transmission region to prevent distortion of the beam spot due to the characteristic difference between the blocking region and the transmission region. 7. An optical pickup apparatus for a heterogeneous optical disc according to claim 6, wherein the phase difference corrected by the coating of the transmission region is lambda / 10 or less. The method of claim 5, wherein the blocking area is An optical pickup apparatus for a heterogeneous optical disc, characterized in that the remaining region is excluded except for the portion corresponding to the opening ratio for the CD. The method of claim 1, wherein the light blocking means An optical pickup device for heterogeneous optical disks, wherein a separate glass substrate is placed in front of the focusing means, and an optical thin film coating for blocking a specific wavelength in a portion of the glass substrate selectively passes the beam according to the wavelength. . 10. The method of claim 9, wherein the optically coated region is An optical pickup apparatus for a heterogeneous optical disc, characterized in that the remaining region is excluded except for the portion corresponding to the opening ratio for the CD. The optical pickup apparatus for a heterogeneous optical disc according to claim 1, wherein the light shielding means and the focusing means are integrated. 12. The optical pickup apparatus for heterogeneous optical disks according to claim 11, wherein the light shielding means is formed by applying an optical coating to the objective lens of the focusing means. The method of claim 12, wherein the first surface of the objective lens An optical pickup apparatus for heterogeneous optical discs, characterized in that it is divided into a blocking region for blocking a specific wavelength and a transmission region for passing an incident beam regardless of the wavelength. The method of claim 1, wherein the light detecting means Optical pickup device for heterogeneous optical disk, characterized in that integral with the light emitting means. The method of claim 14, wherein the light detecting means An optical pickup apparatus for heterogeneous optical discs, characterized in that the beam incident by the integrated light emitting means is detected by diffraction with a hologram element. The method of claim 1, wherein the light detecting means Optical pickup device for heterogeneous optical disk, characterized in that configured separately from the light emitting means. 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; Beam separation means for transmitting or reflecting the incident beam according to the wavelength of the beam emitted from the first and second light emitting means; A band is provided on a part of the lens to reduce the influence of the aberration due to the difference in the thickness of the disk, thereby selectively shielding a part of the beam transmitted or reflected by the beam separating means to condense the light beam on the surfaces of different types of optical disks. Focusing means, And first and second optical detection means for detecting the reflected light beams from the optical disk sequentially through a focusing means and a beam separating means. 18. The optical pickup apparatus for heterogeneous optical disk according to claim 17, wherein the film formed on the lens is an annular film. 18. The optical pickup apparatus of claim 17, wherein the film formed on the lens is a blocking film for blocking the beam. 18. The optical pickup apparatus for heterogeneous optical disk according to claim 17, wherein the film formed on the lens converts the beam by 180 degrees. 18. The apparatus of claim 17, wherein the light detecting means Optical pickup device for heterogeneous optical disk, characterized in that configured separately from the light emitting means. 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 collimator lens for traveling the beam of the first wavelength in parallel in a predetermined direction; A correction lens for correcting the aberration of the beam of the second wavelength, Beam separation means for transmitting or reflecting an incident beam according to the wavelength of the beam passing through the collimator lens or the correction lens; Light blocking means for selectively passing all or part of the incident beam according to the wavelength of the beam transmitted or reflected by the beam separation means; And a focusing means for focusing the light beam on a corresponding surface of the optical disk having different wavelengths, recording densities, and thicknesses by maintaining different numerical apertures according to the amount of light passing through the light shielding means. Device. 23. The method of claim 22, wherein the first light emitting means emits a beam of a wavelength used for the DVD-based optical disk, and the second light emitting means emits a beam of a wavelength used for the CD-based optical disk. Optical pickup device for heterogeneous optical discs. 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; Beam separation means for transmitting or reflecting the incident beam according to the wavelength of the beam generated by the first or second light emitting means; A collimator lens for traveling the light reflected or transmitted by the beam separation means in parallel in a predetermined direction; Light blocking means for selectively passing all or a part of the incident beam incident through the collimator according to the wavelength of the beam; And a focusing means for focusing the light beam on a corresponding surface of the optical disk having different wavelengths, recording densities, and thicknesses by maintaining different numerical apertures according to the amount of light passing through the light shielding means. Device. The method of claim 24, wherein the first and second light emitting means An optical pickup apparatus for heterogeneous optical discs, characterized by outputting wavelengths used for CD-based optical discs and wavelengths used for DVD-based optical discs.