KR100244179B1 - optical pickup device pick-up - Google Patents

Abstract

The present invention relates to an optical pickup device for condensing laser light onto an optical disk using a curved reflective objective lens. In particular, a beam is focused onto an information recording surface of an optical disk using a parabolic curved objective lens. In the reflective objective lens, the front and rear surfaces of which the beam is incident are combined into spherical and aspheric surfaces to focus the beam onto the information recording surface of the optical disk, or the aspherical lens and spherical reflection type on the optical path of the incident beam. The optical pickup is arranged by sequentially placing the objective lens on the information recording surface of the optical disk, or condensing the beam on the information recording surface of the optical disk with the incident side of the reflective objective lens as an aspherical lens and the reflective side as a spherical surface. Thinner and thinner for notebook computers equipped with CD-ROM or DVD-ROM Further, it is easy mass production is light weight a curved path having the aspherical surface or the aspherical surface effect can be injection molded in plastic.

Description

Optical pickup device pick-up

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup apparatus, and more particularly, to an optical pickup apparatus that ultra-thins an optical system by condensing laser light on an optical disk using a curved objective lens.

In general, a compact disc (CD) or a digital versatile disc (DVD) is classified into an optical system, a motor drive system, a signal system, and an operation system. In the optical system, an optical pickup device uses a laser light at a predetermined position of the disk. After projecting, it picks up the reflected light and converts it into an electrical signal.

1 is an optical system configuration diagram of such a general optical pickup device.

1, a laser diode (LD) package 11 generating laser light, a plane mirror 12 reflecting light emitted from the LD package 11 in a vertical direction, and light reflected from the plane mirror 12. And an objective lens 13 for condensing the light at a point on the surface of the optical disc 15, and an actuator 14 for moving the objective lens 13 in the horizontal and vertical directions.

The LD package 11 integrates an LD 11a that emits white light and a photodetector 11b that detects a reflected light beam from the disk 15. The LD 11a and the photodetector 11b are integrated. ) Are arranged side by side, and the beam incident into the LD package 11 is diffracted toward the photodetector 11b using the hologram 11c.

In the optical pickup device configured as described above, laser light generated from the LD 11a of the LD package 11 is incident on the plane mirror 12 through the hologram 11c.

The planar mirror 12 reflects the incident light vertically, and the objective lens 13 installed in the optical path of the reflected beam reflects the incident light by the movement of the actuator 14 provided with the objective lens 13. The light is condensed accurately on the information recording surface (15).

On the other hand, the light beam reflected from the information recording surface of the optical disk 15 is incident to the plane mirror 12 through the objective lens 13, which is the opposite path, and the plane mirror 12 is reflected by reflecting the incident beam in the vertical direction. The beam is incident on the LD package 11.

At this time, the LD package 11 is mounted with the LD 11a and the photodetector 11b side by side, and the beam incident on the LD package 11 is diffracted by the hologram 11c and the photodetector 11b. Incident.

The photo detector 11b 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 this case, the planar mirror of the general optical pickup device as shown in FIG. 1 has a planar inclined surface, and the optical path between the LD package and the objective lens is bent by 90 degrees using the planar mirror, so that other components are optimally designed. Even if the state is maintained, the distance between the planar mirror and the objective lens can no longer be reduced.

In addition, in order to focus the beam on the optical disk, a plurality of lenses such as a flat mirror and an objective lens are required.

Therefore, the thickness and volume of the optical pick-up device become large, and thus the optical system can not be miniaturized or thinned, and when applied to a notebook computer or the like, the thickness of the notebook computer becomes thick and bulky.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an optical pickup device that makes the optical system ultra-thin by replacing planar mirrors and objective lenses with aspherical to aspherical surfaces.

An object according to a first embodiment of the present invention is to provide an optical pickup device that makes an optical system ultra-thin by condensing a beam emitted from LD onto an information recording surface of an optical disk by using a parabolic curved objective lens.

The object according to the second embodiment of the present invention is to combine the front and rear sides of the beam incident in the curved reflective objective lens into spherical and aspherical surfaces to condense the light emitted from the LD onto the information recording surface of the optical disc, An optical pickup device that accurately corrects aberration and makes an optical system ultra thin.

An object according to a third embodiment of the present invention is to sequentially arrange an aspherical lens and a spherical reflective objective lens on an optical path of an incident beam, thereby condensing a beam emitted from the LD onto an information recording surface of an optical disk, thereby aberration is reduced. The present invention provides an optical pickup device that accurately corrects an optical system.

The objective according to the fourth embodiment of the present invention is to correct the aberration accurately by condensing the beam emitted from the LD onto the information recording surface of the optical disc, with the incident side of the reflective objective lens as an aspherical lens and the reflective side as a spherical surface. An ultra-thin optical pickup device is provided.

A feature of the optical pickup device according to the first embodiment of the present invention for achieving the above object is a light source and light for detecting the generation of the laser light and the reflected light beam from the optical disk is composed of a light emitting source and a light receiving source integrally And a reflective objective lens for condensing the light emitted from the light source vertically and then focusing it at a point on the surface of the optical disc.

The optical pickup apparatus according to the second embodiment of the present invention is characterized in that the light source and the light source are integrally formed so that the light source and the light detector for detecting the generation of laser light and the reflected light beam from the optical disk, and the front surface to which the beam is incident And a reflecting objective lens for reflecting the light emitted from the light source vertically and converging at one point on the surface of the optical disk, with the aspherical surface or the spherical surface on which the beam is reflected.

A feature of the optical pickup apparatus according to the third embodiment of the present invention is a light source and a light detector which are integrally formed with a light emitting source and a light receiving source to detect the generation of laser light and the reflected light beam from the optical disk, It comprises an aberration correcting aspherical lens for transmitting the beam and a reflective objective lens installed in the optical path of the beam passing through the aspherical lens to reflect the aberration-corrected incident beam vertically and to focus at a point on the surface of the optical disk It is.

An optical pickup device according to a fourth embodiment of the present invention is characterized in that the light source and the light source are integrally formed to detect a light beam generated from laser light and a reflected light beam from the optical disk, and the incident side is an aspherical lens. The reflective side surface is a spherical surface, and includes a reflective objective lens that vertically reflects a beam generated from the light source and then condenses it at a point on the surface of the optical disk.

1 is a configuration diagram of an optical system of a general optical pickup device

2 is an optical system configuration diagram of an optical pickup apparatus according to a first embodiment of the present invention

3 is an optical system configuration diagram of an optical pickup device according to a second embodiment of the present invention;

4 is a configuration diagram of an optical system of an optical pickup apparatus according to a third exemplary embodiment of the present invention.

5 is a configuration diagram of an optical system of an optical pickup apparatus according to a fourth exemplary embodiment of the present invention.

Explanation of symbols for main parts of the drawings

21: LD package 21a: LD

21b: photo detector 21c: hologram

22, 32, 43, 52: Reflective objective 23: Actuator

24: optical disk

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

First embodiment

2 is an optical system configuration diagram of an optical pickup apparatus according to a first embodiment of the present invention, in which an LD package 21 for generating laser light and a surface on which a beam is incident become a parabolic curved mirror 23a. 21 is integrally installed on the reflective objective lens 22 and the reflective objective lens 22 to reflect light emitted from the light vertically and to focus at one point on the surface of the optical disc 24. And an actuator 23 for moving the 22 in the horizontal and vertical directions.

The LD package 21 integrates the LD 21a for emitting white light and the photo detector 21b for detecting the reflected light beam from the disk 24, and the LD 21a and the photodetector 21b are integrated. ) Are arranged side by side, and the beam incident into the LD package 21 is diffracted toward the photodetector 21b using the hologram 21c.

On the other hand, the parabolic curved surface 23a of the reflective objective lens 22 is off-axis, that is, a non-axis parabolic mirror, which is an aspherical surface.

The aspherical parabolic curved mirror 22a has a radius r depending on the position of the incident beam, and the reflected beam always converges at one point on the optical axis, that is, on the information recording surface of the optical disk 24.

Here, the reflected beam is an aberration beam.

Thus, the optical disk 24 is located between a radius r of the parabola curved mirror 22a and a half point of the radius r of the parabola curved mirror 23a.

According to the first embodiment of the present invention configured as described above, laser light generated from the LD 21a of the LD package 21 is incident on the parabolic curved mirror 22a of the reflective objective lens 22 through the hologram 21c. .

The parabolic curved mirror 22a reflects the incident light and condenses it on the information recording surface of the optical disk 24.

That is, since the parabolic curved mirror 22a is an aspherical surface, the beam reflected from the parabola curved mirror 22a forms a focus on the information recording surface of the optical disk 24 by the movement of the actuator 23.

On the other hand, the light beam reflected from the information recording surface of the optical disk 24 is incident on the parabolic curved mirror 22a of the reflective objective lens 22, which is the opposite path, and the parabola curved mirror 22a directs the incident beam in the vertical direction. The reflected beam is incident on the LD package 21 provided in the light path of the reflected beam.

At this time, the LD package 21 is mounted with the LD 21a and the photodetector 21b disposed side by side, and the beam incident on the LD package 21 is diffracted by the hologram 21c and the photodetector 21b. Incident.

The photo detector 21b 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 this case, the reflective objective lens 22 may be injection molded with plastic, so that the weight is light and easy to mass-produce.

In addition, since the reflection of the incident beam and the condensation on the optical disk 24 are made using one reflective objective lens made of a parabola curved mirror, a plurality of lenses are not required, and the thickness and volume of the optical system are reduced, thereby making it possible to ultra thin.

Second embodiment

3 is an optical system configuration diagram of an optical pickup apparatus according to a second exemplary embodiment of the present invention, which includes an LD package 31 for generating laser light, a front surface 32a through which a beam is incident, and a rear surface reflected after the beam is incident ( A reflective objective lens 32 which combines 32b) as an aspherical surface and a spherical surface to vertically reflect the light emitted from the LD package 31, and then focuses it at a point on the surface of the optical disc 34, and the reflective objective It is integrally installed on the lens 32, and comprises an actuator 33 for moving the reflective objective lens 32 in the horizontal and vertical directions.

The LD package 31 integrates an LD 31a for emitting white light and a photodetector 31b for detecting the reflected light beam from the disk 34. The LD 31a and the photodetector 31b are integrated. ) Are arranged side by side, and the beam incident into the LD package 31 is diffracted toward the photodetector 31b using the hologram 31c.

In addition, the reflective objective lens 32 is composed of one or more bonding surfaces by bonding one or more bonding lenses, and the refractive index of each of the bonding lenses is different.

Here, the front surface 32a on which the beam is incident is made transmissive and the rear surface 32b is made reflective.

The front surface 32a and the rear surface 32b combine spherical surfaces and aspherical surfaces as shown in Table 1 below.

Front Rear Aspheric surface Aspheric surface Aspheric surface Spherical Spherical Aspheric surface

Spherical Spherical

At this time, even if the front surface (32a) and the rear surface (32b) of the spherical surface, spherical surface by the combination of the two spheres has the effect of aspherical surface.

In addition, spherical and aspherical surfaces also have the effect of aspherical surface.

In this case, even when there are a plurality of joint surfaces, if one or more spherical surfaces and aspherical surfaces are appropriately combined with each other, aspherical effects are obtained.

Therefore, the aberration can be corrected more completely.

In the second embodiment of the present invention configured as described above, laser light generated from the LD 31a of the LD package 31 is incident on the incident surface 32a of the reflective objective lens 32 through the hologram 31c.

At this time, since the incident surface 32a is of a transmissive type, the incident beam passes through the front surface 32a as it is and enters the rear surface 32b.

Since the rear surface 32b is of a reflective type, the incident beam is reflected from the rear surface 32b and then forms an optical spot on the information recording surface of the optical disk 34 through the front surface 32a.

That is, since the front surface 32a and the rear surface 32b of the reflective objective lens 32 are combined with each other in spherical and aspherical surfaces to produce an aspherical effect, the beam reflected by the reflective objective lens 32 is an optical disk. Light spots are formed precisely on the information recording surface at (34).

At this time, the incident of the beam generated from the LD package 31 and the emission of the beam to the optical disk 34 are made on the same surface, that is, the front surface 32a.

On the other hand, the light beam reflected from the information recording surface of the optical disk 34 is incident on the front surface 32a of the reflective objective lens 32, which is the opposite path.

At this time, since the front surface 32a is of a transmissive type, the incident beam passes through the front surface 32a as it is and enters the rear surface 32b.

Since the rear surface 32b is a reflective type, the incident beam is reflected from the rear surface 32b and then incident again into the LD package 31 through the front surface 32a.

At this time, the LD package 31 is mounted with the LD 31a and the photodetector 31b disposed side by side, and the beam incident on the LD package 31 is diffracted by the hologram 31c and photodetector 31b. Incident.

The photo detector 31b converts the incident light beam into an electrical signal to obtain a high frequency signal, a focus error signal, and a tracking error signal.

Similarly, the reflective objective lens 32 can also be injection molded from plastic or the like, which is light in weight and easy to mass-produce.

In addition, the use of one reflective objective lens for aspheric effect of reflection of the incident beam and condensation on the optical disk eliminates the need for a plurality of lenses, thereby making the thickness and volume of the optical system small and ultra-thin.

Third embodiment

4 is an optical system configuration diagram of an optical pickup apparatus according to a third embodiment of the present invention.

LD package 41 for generating laser light, aberration correction aspheric lens 42 for transmitting a beam generated in LD package 41, and installed in an optical path of a beam passing through the aspherical lens 42 A reflective objective lens 43 which reflects the incident beam vertically and then focuses it on a point on the surface of the optical disc 45, and is integrally provided with the aspherical lens 42 and the reflective objective lens 43 and integrally provided with the aspherical lens And an actuator 44 for moving the 42 and the reflective objective lens 43 in the horizontal and vertical directions.

The LD package 41 is mounted by arranging the LD 41a and the photodetector 41b side by side as in the first and second embodiments, and are incident into the LD package 41 using the hologram 41c. The beam is diffracted toward the photodetector 41b.

The incident surface 43a of the reflective objective lens 43 is a spherical surface coated with a reflecting mirror.

The spherical surface has a different focusing position of the reflected beam depending on the position of the incident beam, so that the beam is not focused to one point.

However, aspheric effect is obtained by combining the aspherical lens 42 and the spherical surface 43a of the reflective objective lens 43.

Therefore, the aberration can be corrected more completely.

In the third embodiment of the present invention configured as described above, laser light generated from the LD 41a of the LD package 41 is incident on the aspherical lens 42 through the hologram 41c.

The beam whose aberration is corrected by the aspherical lens 42 is incident on the incident surface 43a of the reflective objective lens 43.

At this time, since the incident surface 43a is spherical but has an aspherical effect by being combined with the aspherical lens 42 installed at the front end, the beam reflected vertically from the incident surface 43a of the optical disk 45 An optical spot is formed on the information recording surface.

On the other hand, the light beam reflected from the information recording surface of the optical disk 45 is incident on the incident surface 43a of the reflective objective lens 43 which is the opposite path.

The beam incident on the incident surface 43a is reflected in the vertical direction and is incident on the aspherical lens 42.

The beam whose aberration is corrected by the aspherical lens 42 is incident on the LD package 41.

At this time, the beam incident on the LD package 41 is diffracted by the hologram 41c and is incident on the photodetector 41b.

The photo detector 41b converts the incident light beam into an electrical signal to obtain a high frequency signal, a focus error signal, and a tracking error signal.

Similarly, the reflective objective lens 45 can also be injection molded from plastic or the like, which is light in weight and easy to mass-produce.

In addition, by placing the aspherical lens and the reflective objective lens on the same optical path, the thickness and volume of the optical system can be reduced, thereby making it possible to make ultra thin.

Fourth embodiment

5 is an optical system configuration diagram of an optical pickup apparatus according to a fourth embodiment of the present invention, in which an LD package 51 for generating laser light, the incident side surface 52a is an aspherical lens, and the reflective side surface 52b is a spherical surface. The reflective objective lens 52 reflects the beam generated from the LD package 51 vertically, and the aberration correcting aspherical lens and the spherical surface are integrally formed in one medium. The aspherical surface is perfectly combined with the aspherical surface. The volume can be reduced while correcting.

The reflective objective lens 52 is different from the plane 52a on which the beam generated by the LD package 51 is incident and the plane 52c on which the beam is emitted to the optical disk 54.

That is, the reflector is coated on the spherical surface and the beam reflected from the spherical surface is incident on the optical disk 54 through the emission surface 53a.

In the fourth embodiment of the present invention configured as described above, laser light generated from the LD 51a of the LD package 51 is incident on the incident side surface 52a of the reflective objective lens 52 through the hologram 51c.

Since the incident side surface 52a is an aspherical lens, the incident beam is transmitted to the reflective side surface 52b after the aberration is corrected.

The reflective side surface 52 has a spherical surface, but is combined with the aspherical lens of the incident side surface 52a to have an aspherical effect, so that the reflective side surface 52 reflects the incident beam vertically and then through the exit surface 52c. An optical spot is formed on the information recording surface of the optical disk 54.

On the other hand, the light beam reflected from the information recording surface of the optical disk 54 is incident on the reflective side surface 52b through the exit surface 53c of the reflective objective lens 43 which is the opposite path.

The reflective side surface 52b reflects the incident beam vertically and then enters the LD package 51 through the aspherical lens of the incident side surface 52a.

At this time, the beam incident on the LD package 51 is diffracted by the hologram 51c and incident on the photodetector 51b.

The photo detector 51b converts the incident light beam into an electrical signal to obtain a high frequency signal, a focus error signal, and a tracking error signal.

Similarly, the reflective objective lens 54 can also be injection molded in plastic or the like, which is light in weight and easy to mass-produce.

In addition, by integrating an aspherical lens and a spherical reflective objective lens of one spherical medium, the thickness and volume of the optical system are reduced while the aberration is more accurately corrected, thereby making it possible to achieve ultra-thin thickness.

As described above, since the optical system can be made extremely thin according to the first to fourth embodiments of the present invention, when the CD-ROM or DVD-ROM including the optical pickup device is mounted on the notebook computer, the thickness and volume of the notebook computer can be reduced. do.

According to the optical pickup device according to the present invention as described above, by replacing the conventional flat mirror and objective lens with a reflective objective lens made of parabola curved surface or a curved surface which produces an aspherical effect by combining the spherical surface and the aspherical surface, The thickness can be reduced to about 3mm.

Therefore, the optical system can be made extremely thin, and the thickness and volume of a notebook computer on which a CD-ROM or DVD-ROM is mounted can be made thin.

In addition, since the curved surface having the aspherical surface or the aspherical effect can be injection-molded with plastic or the like, it is light in weight and easy to mass-produce.

Claims (16)

delete delete delete delete delete A light source and a light detector which are integrally formed with a light emitting source and a light receiving source to detect the generation of laser light and the reflected light beam from the optical disk; And a reflective objective lens for converging the light emitted from the light source vertically, with the front surface where the beam is incident and the rear surface where the beam is reflected as the aspherical surface or the spherical surface, respectively. Optical pickup device. delete delete delete delete delete delete delete delete A light source and a light detector which are integrally formed with a light emitting source and a light receiving source to detect the generation of laser light and the reflected light beam from the optical disk; An aspherical lens for correcting aberration for transmitting a beam generated from the light source; And a reflective objective lens installed in the optical path of the beam passing through the aspherical lens to reflect the aberration-corrected incident beam vertically and to focus at a point on the surface of the optical disk. A light source and a light detector which are integrally formed with a light emitting source and a light receiving source to detect the generation of laser light and the reflected light beam from the optical disk; The optical pick-up apparatus, characterized in that the incident side is an aspherical lens and the reflective side is a spherical surface, and includes a reflective objective lens for reflecting the beam generated from the light source vertically and condensing at a point on the surface of the optical disk. .

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