KR100562338B1 - Optical pickup apparatus - Google Patents

Abstract

An optical pickup apparatus for recording or reproducing information on an optical recording medium having a substrate and a signal recording surface includes a light source unit for generating and emitting a beam, and an optical member for condensing the beam from the light source unit on the signal recording surface of the optical recording medium. In addition, the information recorded on the optical recording medium can be recorded or reproduced. The optical member is composed of an incidence surface to which a beam from the light source unit is incident, a partial reflection surface, a concave reflection surface and an outgoing surface that partially reflects the beam passing through the incidence surface, and the partial reflection surface is configured to transmit the beam from the light source unit to its optical axis. The light is partially reflected in the approximately 90 ° direction, and the concave reflection surface reflects and condenses the beam reflected from the partial reflection surface toward the optical recording medium.

Optical pickup device, optical recording medium, optical disc, near field effect, remote field effect, partial reflection

Description

Optical pickup apparatus

1 is a view showing an optical pickup device according to a first embodiment of the present invention,

2 is a view for explaining each block of the optical member of the first embodiment of the present invention,

3 and 4 are views showing another example of the optical pickup apparatus according to the first embodiment of the present invention,

FIG. 5 is a diagram for explaining forming a hologram of the partially reflective surface of the optical member of FIG. 3 or 4;

6 is a view showing an optical pickup apparatus according to a second embodiment of the present invention,

7 is a view for explaining each block of the optical member of the second embodiment of the present invention,

8 and 9 illustrate another example of the optical pickup apparatus according to the second exemplary embodiment of the present invention.

10A and 10B are views for explaining forming a hologram of the partially reflective surface of the optical member of FIG. 8 or 9;

11 is a schematic diagram of an optical pickup apparatus according to the prior art,

FIG. 12 illustrates the shape of an optical spot formed on a signal recording surface of an optical recording medium in the optical pickup device of FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup apparatus for recording and reproducing information on an optical recording medium such as an optical disc. In particular, the present invention can be used or applied to both recording and reproducing by far field and near field effects. An optical pickup apparatus.

Background Art In recent years, densification of optical recording media such as optical discs and magneto-optical discs as a recording medium of a computer recording device, music, and image information has been advanced. In order to increase the density of the optical recording medium, it is necessary to reduce the size of the optical spot of the optical pickup apparatus for recording and reproducing information, and to miniaturize the optical pickup apparatus.

Due to this necessity, as proposed in US Pat. No. 6,275,453, a small optical pickup device using a transparent optical member that reflects incident light on a spherical or aspheric reflective surface and is directed perpendicular to the direction of incidence. However, this optical pickup device shown in FIG. 11 uses one non-axis reflecting surface 7 of the transparent optical member 6, so that the shape of the light spot finally incident on the optical disk 8 is not circular. As shown in Fig. 12, the shape spreads to the left so that the information stored on the optical disc cannot be reproduced or recorded. The shape of the optical spot is distorted because the incident beams incident on the signal recording surface of the optical disc have different convergence angles of marginal rays about the optical axis. That is, in Fig. 11, the values of θ1 and θ2 are different.

Accordingly, an object of the present invention is to provide an improved optical pickup device which solves the above-mentioned problems, wherein the shape of the optical spot focused on the optical recording medium is close to the ideal circular shape and enables high density recording and reproduction. To provide.

Another object of the present invention is to provide an optical pickup apparatus which can be used for recording and reproducing various kinds of optical recording media.

In order to achieve the above object, the present invention is an optical pickup device for recording information on or reproducing recorded information on an optical recording medium having a substrate and a signal recording surface, comprising: a light source unit for generating and emitting a beam and a beam from the light source unit; And an optical member for condensing on the signal recording surface of the optical recording medium.

The optical member reflects the beam from the light source unit,

A partial reflecting surface that partially reflects the beam emitted from the light source in the direction of approximately 90 ° to the optical axis;

The beam reflected from the partially reflective surface is reflected and collected again toward the optical recording medium, and is made of a concave reflective surface concave toward the optical recording medium.

In addition, the optical member may preferably further include an incident surface on which the beam from the light source unit is incident and an exit surface on which the beam reflected from the concave reflection surface exits.

On the other hand, the partially reflective surface is preferably formed at an angle of approximately 45 ° or less with the optical axis of the incident beam, and the reflective grating or hologram may be formed on the partially reflective surface.

Hereinafter, with reference to the accompanying drawings will be described an embodiment according to the present invention. The present invention can be used for recording / reproducing all optical recording media such as a near field type high density optical recording medium as well as a conventional long field type optical recording medium such as a general compact disc (CD) or a digital multifunction disc (DVD).

First, referring to FIG. 1, an optical pickup apparatus according to a first exemplary embodiment of the present invention is illustrated. The optical pickup apparatus according to the first exemplary embodiment relates to an optical pickup apparatus using an infinite optical system, and includes an optical member 200 and a light source unit 100 that emits parallel beams. The light source unit 100 emits a parallel beam including a light emitting element that is a laser diode and a collimator lens.

The optical member 200 is formed of a plane incidence surface 210, a partial reflection surface 220, a concave reflection surface 230, and an emission surface 240, and is formed of a transparent optical material having a refractive index of 1.0 or more. .

The partial reflection surface 220 is formed to form an angle of 45 ° or less with the optical axis of the incident beam, and is a surface that transmits a part of the incident beam and reflects the rest. The concave reflecting surface 230 is a concave spherical or aspheric surface when viewed from the incident beam side, and is coated with a metal or other reflecting material to the outside thereof so as to reflect light propagating therein.

The exit surface 240 may be formed as a spherical surface, an aspherical surface, or a planar surface. When the exit surface 240 is formed as a spherical surface or aspherical surface toward the optical disk, the converging beam may further focus to increase the numerical aperture. 1 shows a spherical or aspherical surface having a large radius of curvature. In addition, although not shown, a replica lens may be formed on the planar exit surface 240 to reduce various optical aberrations. Replica lenses are used to enhance optical performance by coating materials with different optical properties in a plane, spherical or aspherical shape, on the exit surface, from several micrometers to several tens of micrometers thick. That is, it can be used to minimize the desired optical path aberration by removing various aberrations including spherical aberration, power increase, astigmatism, coma, chromatic aberration, etc. To chemical stability and can be used to improve optical properties.

On the other hand, the optical member 200 may be manufactured by dividing into several blocks for convenience in manufacturing and then bonding. For example, as shown in FIG. 2, the optical member 200 is divided into blocks of A to C, formed of a transparent optical material, and then bonded by partially reflective coating on the bonding surfaces of A and B, and the remaining blocks are respectively positioned. Bond to. At this time, the material of each block may be the same and have the same refractive index, or the material of each block may be different and have different refractive indices. Each block has a refractive index of 1.0 or greater.

It is also possible to divide each block according to the ease of the manufacturing process. That is, A and C blocks may be manufactured in one block, and B and D may be manufactured in one block, and the joint surface may be partially bonded and then bonded to each other.

The operating principle of the optical pickup device shown in FIG. 1 is that a parallel beam generated by the light source unit 100 is incident through the incident surface 210 of the optical member 200, and then a part of the incident beam is incident on the partial reflection surface 220. The beam reflects perpendicularly to the original traveling direction and is directed to the concave reflecting surface 230, and the beam reflected from the concave reflecting surface 230 so as to converge is passed through the partial reflecting surface 220 as it is to the exit surface 240. Is headed. At this time, since the beam toward the exit surface 240 is focused by the concave reflection surface 230 which is an on-axis optical system, the convergence angle of the edge rays becomes equal. Therefore, the shape of the beam spot formed on the optical disc 300 is close to the ideal circle. The emission surface 240 of the optical member 200 shown in FIG. 1 is composed of a spherical or aspherical surface that is convex toward the optical disk, thereby converging the converged beam to further converge to increase the numerical aperture.

The beam focused on the optical disc 300 is reflected on the signal recording surface of the optical disc and then directed back to the light source unit 100 via the optical member 200 and is incident on the light receiving element through a beam splitter and an optical system not shown in the light source unit 100. Thus, a signal recorded on the optical disc is reproduced or a signal is recorded on the optical disc.

Table 1 shows a specific example of the optical pickup device used in the form of a far field when the optical member 200 of FIG. 1 is used.

if Bending Radius (mm) and Shape Factor Distance (mm) Refractive index Entrance ∞ 1.5 1.51 Partial reflection ∞ Clockwise rotation around the x axis ADE -45.0 ° -1.0 (reflective) Reflective surface Concave reflection 5.9258 Conic constant K -1.0 Clockwise rotation around the x axis ADE -45.0 ° 2.6 Reflective surface Exit surface -2.536 Conic Constant K -14.214 0.6 air disk ∞ 0.6

If the optical pickup apparatus shown in FIG. 1 is a remote field optical pickup apparatus for an optical recording medium such as a CD or a DVD, an example in which the present invention is applied to a near field type optical pickup apparatus will be described with reference to FIGS. .

First, referring to FIG. 3, the optical pickup apparatus using the near field effect includes a light source unit 100 and an optical member 200 that emit parallel beams. The optical member 200 is composed of an incident surface 210, a partially reflective surface 220, a concave reflective surface 230, and an exit surface 240, and a refractive index thereof is usually formed of a transparent optical material having a high refractive index of 1.5 or more. In addition, the optical member 200 is an incident surface 210 is a plane, the partial reflecting surface 220 is a reflective grating or reflective hologram surface formed to form an angle of 45 ° or less with the optical axis of the incident light, concave reflective surface 230 Silver is a concave spherical or aspherical surface as viewed from the incident light side, and is coated with a metal or other reflective material on the outside thereof. The exit surface 240 is planar, and is disposed in close proximity to the optical disk 300.

In the near field method, although the numerical aperture must be high, when the partial reflecting surface 220 is inclined at 45 ° to the incident light and the diameter of the incident beam is d, the diameter of the incident surface 210 should be at least the diameter d of the beam. The degree of convergence θ of the beam reflected from the reflecting surface 230 and converged is

It becomes smaller than 26.5 degrees which satisfy | fills N, and numerical aperture becomes nx0.45 (where n is refractive index of an optical member) or less. Therefore, when the inclination angle (angle formed with the optical axis of the incident beam) of the partial reflection surface 220 is made smaller than 45 °, the numerical aperture of the near field optical system can be made higher than n × 0.45.

However, when the inclination angle of the partial reflection surface 220 is smaller than 45 °, since the reflection angle of the incident beam becomes larger than 45 °, the optical axis of the reflection beam at the partial reflection surface 220 is the concave reflection surface 230. It is shifted from the center of rotation of the axis and cannot proceed in the direction perpendicular to the incident beam. Therefore, grating is performed in order to proceed in a direction coinciding with the central axis of rotation of the concave reflection surface 230, that is, a direction perpendicular to the incident beam, to the concave reflection surface 230. Or a hologram is formed on the partially reflective surface.

The method of forming the grating or the hologram on the partial reflecting surface 220 is a reference beam (R) and the object beam (O) parallel to the partial reflecting surface inclined at the inclination angle φ of the designed partial reflecting surface as shown in FIG. The method of optically forming by interference and the method of mechanically forming a pattern of predetermined intervals can be used. After the partial reflection coating is applied to the grating or hologram thus formed and bonded to other blocks, the final optical member 200 may be manufactured by dividing into several blocks as described with reference to FIG. 2.

The optical pickup apparatus according to the present embodiment is for use in the optical disc 300 having the signal recording surface 301 on which information is recorded on the substrate 302. The parallel beam emitted from the light source unit 100 is incident on the incident surface 210 of the optical member 200, and is first diffracted and reflected in the reflective grating (or the reflective hologram) of the partially reflective surface of the optical member, so that the parallel beam is perpendicular to the incident beam. The concave reflective surface 230 is directed. The beam reflected from the concave reflection surface 230 so as to converge and passed through the partial reflection surface 220 as it is is collected at the exit surface 240. At this time, the exit surface 240 and the signal recording surface 301 of the optical disk are sufficiently close so that the information recorded on the signal recording surface 301 of the optical disk can be reproduced or the information can be recorded on the signal recording surface 301 of the optical disk by the near field effect. Will be.

Meanwhile, the optical pickup apparatus using the near field effect illustrated in FIG. 4 includes a light source unit 100 and an optical member 200 that emit parallel beams. The optical pickup device shown in FIG. 4 is similar to the optical pickup device shown in FIG. 3, but has a slightly different structure of an optical disc 300 that can be reproduced and recorded. That is, the optical disk 300 of FIG. 4 is a kind of reproducing and recording information recorded on the signal recording surface 301 by the light incident through the substrate 302. The present invention can be applied to an optical pickup apparatus for such an optical disk. . That is, the optical pickup device of FIG. 4 includes a light source unit 100 and an optical member 200 that emit parallel beams. The optical member 200 includes an incident surface 210, a partial reflective surface 220, a concave reflective reflective surface 230, and an exit surface 240, and the refractive index of the optical member 200 is formed of a transparent optical material having a high refractive index of 1.5 or more. In addition, the optical member 200 is an incident surface 210 is a plane, the partial reflecting surface 220 is a reflective grating or hologram surface formed to form an angle of 45 ° or less with the optical axis of the incident light, the concave reflective surface 230 It is a concave spherical or aspherical surface when viewed from the incident light side and coated with a metal or other reflective material on the outside thereof. The exit surface 240 is planar, and is disposed in close proximity to the optical disk 300.

In the optical pickup apparatus according to the present exemplary embodiment, the parallel beam from the light source unit 100 is incident on the incident surface 210 of the optical member 200, and then the reflection beam grating (or the reflective hologram) of the partially reflective surface 220 of the optical member 200 is performed. The first diffracted reflection is directed toward the concave reflective surface 230 in a direction perpendicular to the incident beam. The beam reflected from the concave reflection surface 230 so as to converge is passed through the partial reflection surface 220 as it is directed toward the exit surface 240. At this time, the converged light finally emitted from the emission surface 240 is focused on the signal recording surface 301 through the substrate 302 of the optical disk 300. At this time, the exit surface 240 and the substrate 302 of the optical disk are sufficiently close so that the information recorded on the signal recording surface 301 of the optical disk can be reproduced or the information can be recorded on the signal recording surface 301 of the optical disk by the near field effect. do.

On the other hand, in the case of near-field recording focused on the signal recording surface 301 through the substrate 302 as shown in FIG. 3 or 4, the signal recording surface is caused by the thickness of the optical member 200 and the thickness of the substrate 302 of the optical disk. The case where the light spot cannot be formed exactly at 301 occurs. In this case, it can be solved as proposed by the Infinite Optical System in the applicant's patent application 10-2002-0009877 "optical pickup device that can compensate for the thickness variation of the optical recording medium," the application is referred to herein Forms part of. That is, the light source unit 100 is composed of a light emitting element and a collimator lens, which is a conventional laser diode, and shifts the position of the light emitting element or collimator lens so as to correspond to the thickness variation of the optical member 200 or the optical recording medium substrate, thereby causing a thickness variation. By this, parallel light is made into divergent light or converging light, and finally the light recording surface is formed without aberration on the signal recording surface.

Next, referring to FIG. 6, an optical pickup apparatus according to a second exemplary embodiment of the present invention is illustrated. The optical pickup apparatus according to the second exemplary embodiment relates to an optical pickup apparatus using a finite optical system, and includes an optical member 200 and a light source unit 100 for emitting a diverging beam.

The optical member 200 is formed of an incident surface 210, a partially reflective surface 220, a concave reflective surface 230, and an exit surface 240, and is formed of a transparent optical material having a refractive index of 1.0 or more.

The incident surface 210 has a concave spherical or aspherical surface when viewed from the incident beam side, thereby reducing the aberration of the diverging beam.

The partial reflection surface 220 is formed to form an angle of 45 ° or less with the optical axis of the incident light, and is a surface that transmits a part of incident light and reflects the rest. The concave reflection surface 230 is a concave or aspherical surface concave when viewed from the incident light side, and is coated with a metal or other reflective material to the outside thereof.

The exit surface 240 is made up of a flat, spherical or aspherical surface. That is, it may be made of a spherical or aspherical surface convex toward the optical disk to increase the numerical aperture, or a replica lens may be formed to reduce various optical aberrations.

In the meantime, the optical member 200 may be manufactured by dividing the optical member 200 into blocks as in the first embodiment and then attaching them for convenience in manufacturing. For example, as shown in FIG. 7, the optical member 200 may be divided into blocks of E to H, and although not shown, an additional block may be formed toward the exit surface, and one block of E to G may be formed. It is also possible to produce a block of and combine with an H block. At this time, the material of each block may be the same to have the same refractive index, and the material of each block may be different to have a different refractive index from each other as in the first embodiment. Each block has a refractive index of 1.0 or greater.

The operating principle of the optical pickup device shown in FIG. 6 is that a diverging beam generated by the light source unit 100 is incident through the incident surface 210 of the optical member 200, so that a part of the incident beam is partially generated at the partially reflective surface 220. Is reflected perpendicularly to the optical axis direction of the beam toward the concave reflection surface 230, the beam is reflected so as to converge the beam from the concave reflection surface 230 is passed through the partial reflection surface 220 as it is directed toward the exit surface 240 do. At this time, since the beam toward the exit surface 240 is focused by the concave reflection surface 230 which is the forward axis optical system, the convergence angle of the edge rays becomes equal. Therefore, the shape of the beam spot formed on the optical disc 300 is close to the ideal circle.

The beam focused on the optical disc 300 is reflected on the signal recording surface of the optical disc and then directed back to the light source unit 100 via the optical member 200 and is incident on the light receiving element through a beam splitter and an optical system not shown in the light source unit 100. Thus, the signals recorded on the optical disc are reproduced or the signals are recorded on the optical disc.

Table 2 shows a specific example of the optical pickup apparatus of the remote field method when the optical member 200 of FIG. 6 is used.

if Bending Radius (mm) and Shape Factor Distance (mm) Refractive index Light source 6.0 air Entrance -6.0 3.0 1.514 Partial reflection Bending Radius ∞ Parallel Shift 1.127899 Clockwise Rotation -45.00 ° -1.62 (reflective) 1.514 Concave reflection Bending radius 7.16291 Conic constant -0.544021 Clockwise rotation value -45.00 ° 3.65 1.514 Exit surface -38.94882 0.832 air Disc face ∞ 0.6 1.514

If the optical pickup apparatus shown in FIG. 6 is a remote field optical pickup apparatus for an optical recording medium such as a CD or a DVD, an example in which the present invention is applied to an optical pickup apparatus of a near field method will be described with reference to FIGS.

First, referring to FIG. 8, an optical pickup apparatus using a near field effect includes a light source unit 100 and an optical member 200 that emit divergent beams. The optical member 200 is composed of an incident surface 210, a partially reflective surface 220, a concave reflective surface 230, and an exit surface 240, and a refractive index thereof is usually formed of a transparent optical material having a high refractive index of 1.5 or more. In addition, the optical member 200 is a spherical or aspherical surface in which the incident surface 210 is concave, and the partial reflective surface 220 is a reflective hologram surface formed to form an angle of 45 ° or less with the optical axis of the incident light, and the concave reflective surface 230 Silver is a concave spherical or aspherical surface viewed from the incident light side and coated with a metal or other reflective material on the outside thereof. The exit surface 240 is formed in a plane, and is disposed in close proximity to the optical disk 300.

As described in the optical pickup apparatus of FIG. 3, the partially reflective surface 220 may have a high numerical aperture when the inclination angle is smaller than 45 °. Although the partial reflection surface 220 is formed to have an angle smaller than 45 ° with the optical axis of the incident light, a hologram is formed on the partial reflection surface in order to reflect the reflected light in a direction perpendicular to the incident light to the concave reflection surface 230.

The method of forming the hologram on the partial reflecting surface 220 interferes with the object beam O parallel to the reference beam R, which diverges on the partially reflecting surface inclined at the inclination angle φ of the designed partial reflecting surface as shown in FIG. 10A. Optically or by interfering with the diverging reference beam R and the diverging object beam O, as shown in FIG. 10B. The difference using a beam that emits an object beam or a parallel beam may be determined depending on whether the concave reflective surface 230 of the optical member is an aspherical surface approaching an ellipsoid or an aspherical surface approaching a parabola. After the partial reflection coating is applied to the hologram formed as described above, it is used by bonding with other blocks. The final optical member 200 may be manufactured by dividing into several blocks as described with reference to FIG. 7.

The optical pickup apparatus according to the present embodiment is for use in the optical disc 300 having the signal recording surface 301 on which information is recorded on the substrate 302. The beam emitted from the light source 100 enters the incident surface 210 of the optical member 200 and is first diffracted and reflected in the reflective hologram of the partially reflective surface of the optical member to concave reflective surface perpendicular to the optical axis of the incident beam. Headed to (230). The beam reflected from the concave reflection surface 230 so as to converge is passed through the partial reflection surface 220 as it is directed to the exit surface 240. At this time, the converged light finally emitted from the emission surface 240 is focused on the signal recording surface 301 through the substrate 302 of the optical disk 300.

Meanwhile, the optical pickup apparatus using the near field effect illustrated in FIG. 9 includes a light source unit 100 and an optical member 200 that emit divergent beams. The optical pickup device shown in FIG. 9 is a type for reproducing and recording information recorded on the signal recording surface 301 by the light incident through the substrate 302 as in the optical disk shown in FIG. The optical member 200 is composed of an incident surface 210, a partially reflective surface 220, a concave reflective surface 230, and an exit surface 240, and a refractive index thereof is usually formed of a transparent optical material having a high refractive index of 1.5 or more. In addition, the optical member 200 is a spherical or aspherical surface in which the incident surface 210 is concave, and the partial reflective surface 220 is a reflective hologram surface formed to form an angle of 45 ° or less with the optical axis of the incident light, and the concave reflective surface 230 Is concave or aspherical when viewed from the incident light side. The emission surface 240 is formed in a plane and is disposed in close proximity to the optical disk 300.

The optical pickup apparatus according to the present embodiment is for use in the optical disc 300 having a signal recording surface 301 on which information is recorded on the substrate 302. The divergent beam emitted from the light source unit 100 enters the incident surface 210 of the optical member 200 and is first diffracted and reflected in the reflective hologram of the partially reflective surface of the optical member, thereby concave reflective surface perpendicular to the optical axis of the incident beam. Headed to (230). The beam reflected from the concave reflection surface 230 so as to converge is passed through the partial reflection surface 220 as it is directed toward the exit surface 240. At this time, the converged light finally emitted from the emission surface 240 is focused on the signal recording surface 301 through the substrate 302 of the optical disk 300. At this time, the exit surface 240 and the substrate 302 of the optical disk are sufficiently close so that the information recorded on the signal recording surface 301 of the optical disk can be reproduced or the information can be recorded on the signal recording surface 301 of the optical disk by the near field effect. do.

8 and 9, although not shown, a replica lens may be added to the incident surface 210 of the optical member 200.

On the other hand, in the case of near field recording focused on the signal recording surface 301 through the substrate 302 as shown in FIG. 8 or 9, the signal recording surface is caused by the error of the thickness of the optical member 200 and the thickness of the substrate 302 of the optical disk. The case where the light spot cannot be formed exactly at 301 occurs. In this case, as described above with reference to FIG. 3 or 4, the position of the light emitting device used as the light source unit may be moved to adjust the image position according to the thickness variation. It can also be solved as proposed in the patent application 10-2002-0009877 "optical pickup device that can compensate for the thickness variation of the optical recording medium", and the information on the studying optical system forms a part of the present invention with reference to the present specification. . That is, the light source unit 100 is composed of a light emitting element such as a conventional laser diode, and moves the position of the light emitting element so as to correspond to the thickness variation of the optical member or the optical recording medium substrate, the light emitting element and the optical member of the present invention By shifting the distance finely, the thickness of the optical member 200 and the thickness variation of the optical disk are compensated to finally form an optical spot without aberration on the signal recording surface.

The optical pickup device according to the present invention can be applied not only to general optical field devices such as CDs and DVDs but also to near field type optical pickup devices, and thus has a wide range of application.

In addition, by using the partial reflecting surface and the concave reflecting surface, the angle formed by the beam coming from the light source unit and the beam which is finally focused can be set to 90 °, so that not only a small optical pickup device can be realized but also the light condensed on the optical recording medium. The shape of the spot can be made close to the ideal circle, so that high density recording and reproduction can be performed.

Furthermore, since the optical member of the present invention can be manufactured by dividing into several blocks, the mold used in the conventional beam splitter and the lens can be used, and thus the cost can be reduced and easily produced by manufacturing a new mold. It can manufacture.

Although the technical features of the present invention have been described above with reference to specific embodiments, those skilled in the art to which the present invention pertains may make various changes and modifications within the scope of the technical idea according to the present invention. It is obvious.

Claims (20)

delete delete delete An optical pickup apparatus for recording information or reproducing recorded information on an optical recording medium having a substrate and a signal recording surface, A light source unit generating and emitting a beam; An optical member for condensing the beam emitted from the light source to the signal recording surface of the optical recording medium Including, The optical member An incident surface to which the beam from the light source unit is incident; A partial reflecting surface that partially reflects the beam passing through the incident surface in a direction approximately 90 ° with the optical axis; A concave reflecting surface that reflects and condenses the beam reflected from the partially reflecting surface back to the optical recording medium, and is concave toward the optical recording medium; An emission surface from which the beam reflected from the concave reflection surface exits Including, And the partial reflecting surface is formed to form an angle of approximately 45 ° or less with the optical axis of the incident beam, and a grating is formed on the partial reflecting surface. An optical pickup apparatus for recording information or reproducing recorded information on an optical recording medium having a substrate and a signal recording surface, A light source unit generating and emitting a beam; An optical member for condensing the beam emitted from the light source to the signal recording surface of the optical recording medium Including, The optical member An incident surface to which the beam from the light source unit is incident; A partial reflecting surface that partially reflects the beam passing through the incident surface in a direction approximately 90 ° with the optical axis; A concave reflecting surface that reflects and condenses the beam reflected from the partially reflecting surface back to the optical recording medium, and is concave toward the optical recording medium; An emission surface from which the beam reflected from the concave reflection surface exits Including, And the partial reflecting surface is formed to form an angle of approximately 45 ° or less with the optical axis of the incident beam, and a hologram is formed on the partial reflecting surface. The method according to claim 4 or 5, And the optical member is a plurality of blocks bonded to each other. The method according to claim 4 or 5, And a light beam emitted from the light source unit is a collimated beam. The method according to claim 4 or 5, And a divergent beam from which the light from the light source is emitted. The method according to claim 4 or 5, And the optical pickup apparatus performs optical recording and reproduction by a far field effect. The method according to claim 4 or 5, And the refractive index of the optical member is 1.5 or more, and the emission surface of the optical member is located in close proximity to the optical recording medium to perform optical recording and reproduction by a near field effect. The method of claim 10, And the optical member is formed so that the beam reflected from the second reflecting surface is focused at the exit surface of the optical member. The method of claim 10, The optical recording medium is to record and reproduce information on the signal recording surface through the substrate, And the optical member is formed such that the beam reflected from the concave reflection surface is focused on the signal recording surface through the emission surface and the substrate of the optical member. delete An optical pickup apparatus for recording information or reproducing recorded information on an optical recording medium having a substrate and a signal recording surface, A light source unit generating and emitting a beam; An optical member for condensing the beam emitted from the light source to the signal recording surface of the optical recording medium Including, The optical member An incident surface to which the beam from the light source unit is incident; A partial reflecting surface that partially reflects the beam passing through the incident surface in a direction approximately 90 ° with the optical axis; A concave reflecting surface that reflects and condenses the beam reflected from the partially reflecting surface back to the optical recording medium, and is concave toward the optical recording medium; An emission surface from which the beam reflected from the concave reflection surface exits Including, And the incidence surface is selected from a plane, a spherical surface, and an aspherical surface, and a replica lens is formed on the incidence surface. delete An optical pickup apparatus for recording information or reproducing recorded information on an optical recording medium having a substrate and a signal recording surface, A light source unit generating and emitting a beam; An optical member for condensing the beam emitted from the light source to the signal recording surface of the optical recording medium Including, The optical member An incident surface to which the beam from the light source unit is incident; A partial reflecting surface that partially reflects the beam passing through the incident surface in a direction approximately 90 ° with the optical axis; A concave reflecting surface that reflects and condenses the beam reflected from the partially reflecting surface back to the optical recording medium, and is concave toward the optical recording medium; An emission surface from which the beam reflected from the concave reflection surface exits Including, And the emission surface is selected from a plane, a spherical surface, and an aspherical surface, and a replica lens is formed on the emission surface. An optical pickup apparatus for recording information or reproducing recorded information on an optical recording medium having a substrate and a signal recording surface, A light source unit generating and emitting a beam; An optical member for condensing the beam emitted from the light source to the signal recording surface of the optical recording medium Including, The optical member A partial reflecting surface that partially reflects the beam emitted from the light source portion in a direction approximately 90 ° with the optical axis; A concave reflecting surface that reflects and condenses the beam reflected from the partial reflecting surface back to the optical recording medium and is concave toward the optical recording medium Including, The optical pickup device, characterized in that the concave reflection surface is coated with a metal film on the outside. An optical pickup apparatus for recording information or reproducing recorded information on an optical recording medium having a substrate and a signal recording surface, A light source unit for generating and emitting a collimated beam, including a light emitting element and a collimator lens for making light emitted from the light emitting element into a parallel beam; An optical member for condensing the beam from the light source unit on the signal recording surface of the optical recording medium; Position adjustment unit connected to the light emitting element or collimator lens, to move the position of the light emitting element or collimator lens Including, The optical member A partial reflecting surface that partially reflects the beam emitted from the light source portion in a direction approximately 90 ° with the optical axis; A concave reflecting surface that reflects and condenses the beam reflected from the partial reflecting surface back to the optical recording medium and is concave toward the optical recording medium Including; And adjusting the position of the light emitting element or the collimator lens to compensate for the thickness variation of the optical member or the optical recording medium. An optical pickup apparatus for recording information or reproducing recorded information on an optical recording medium having a substrate and a signal recording surface, A light source unit including a light emitting element to generate and emit a divergent beam; An optical member for condensing the beam from the light source unit on the signal recording surface of the optical recording medium; A position adjusting unit connected to the light emitting device to move the position of the light emitting device; Including, The optical member A partial reflecting surface that partially reflects the beam emitted from the light source portion in a direction approximately 90 ° with the optical axis; A concave reflecting surface that reflects and condenses the beam reflected from the partial reflecting surface back to the optical recording medium and is concave toward the optical recording medium Including; And adjusting the position of the light emitting element to compensate for the thickness variation of the optical member or the optical recording medium. The method of claim 6, And wherein each block is formed of a material having a refractive index of 1.0 or greater.

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