KR20030080878A - Micro Optic Device for pick-up - Google Patents

Abstract

PURPOSE: A small optical element for an optical pickup is provided to form components on a substrate to be mounted at a portable terminal, thereby storing information on a disk through the portable terminal. CONSTITUTION: A swing arm(51) connects an end of a substrate according to weight of an optical element(53), and has a reflecting mirror(55) formed at an end for converting a path of a laser beam to send the laser beam in a direction of an optical information recording medium(56). A slider(58) is placed between a lower part of the reflecting mirror and the optical information recording medium. The slider includes a suspension(59) connected with the swing arm, and an objective lens(57) and a solid immersion lens for focusing the laser beam. The slider maintains a certain gap with a surface of the optical information recording medium. A near field optical pickup system applies the laser beam horizontally proceeded to the surface of the medium to the medium.

Description

Micro Optic Device for pick-up

The present invention relates to a small optical element for optical pickup.

Recently, unlike the conventional optical pickup (pick up), in the data play (DataPlay), the pickup structure is simplified, and photoelectric devices such as laser devices LD and photodiodes PD are manufactured on one substrate. The optical pickup device is configured by blocking the remaining optical components into one, which is illustrated in FIG.

Fig. 1 shows a cross-sectional view of a miniature optical element for optical pickup according to the prior art, wherein the miniature optical element shown in Fig. 1 is a system for reading an optical disc 10 mounted on a swing arm.

This is to block the optical system configuration of the P / U (Pick Unit) such as a conventional beam splitter (beam splitter) and the lens into one, and the operation thereof will be described as follows.

A laser diode (LD) 1 and an LD submount 2 are attached onto the Si submount 3 to drive the LD 1 through a high frequency module (HFO) 4.

When the LD 1 is turned on, the light is reflected by the turning mirror 5 and moved upwards, and reflected by the beam splitter 11 of the periscope 6, and the ferry Go to the beam splitter 1 (7) of the scope (6) and reflect back up, and then pass through a quarter wave plate (QWP) 8 for isolating the light back to the LD (1). , OL) 9 focuses on the recording surface of the disc 10.

The light reflected back from the disk 10 is returned as it is, part of which is reflected by the QWP 8 and goes down, and the other part is reflected, and part of the beam splitter 1 7 goes down and the other is reflected. Reflected at (12) and down, the light transmitted from the beam splitter 1 (7) and the light reflected from the reflecting surface 12 are transferred through the PD (photo diode) fabricated on the surface of the Si submount 3. The signal is converted into a signal and the signal recorded on the disk 10 is read.

Here, the spacers 13 and 14 are mechanisms for assembly and the OE block 15 is an instrument for reading a write signal. The optical element is about 5 mm high and about 2 mm wide.

The structure of the optical pickup of DataPlay according to the related art described above has a height of about 5 mm and a width of about 2 mm, which is small and portable because of its height limitation in application to portable devices that are becoming lighter and lighter. There is a problem in that devices such as terminals cannot be mounted.

Therefore, in order to overcome this height limitation, the height of the optical element for the optical pickup is further limited to about 1 to 2 mm, and the width should be about 3 to 4 mm.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to miniaturize an optical device for optical pickup using a near field or a general optical field.

Another object of the present invention is to fabricate an existing optical pickup element composed of several components into a single body and to reduce the size thereof, and to apply it to a portable telephone or other portable product using the miniaturized optical element.

1 is a cross-sectional view of a miniature optical element for optical pickup according to the prior art.

2 is a perspective view and a plan view of a miniature optical element for optical pickup according to the present invention.

FIG. 3A shows a laser beam radiation form of a general LD, and FIG. 3B shows a radiation form of a laser beam corrected using a small cylindrical lens.

Fig. 4 shows the structure of the entire system in which the small optical element as shown in Fig. 2 according to the present invention is located, and in particular the optical system in the near field method.

Fig. 5A is a cross sectional view showing a combination of an objective lens and a swing arm in the case of a near field method.

FIG. 5B is a cross-sectional view showing a combination of an objective lens and a swing arm in the case of a general optical field method.

6 is a perspective view and a plan view of a miniature optical element for an optical pickup of a magneto-optical type according to a first embodiment according to the present invention.

FIG. 7 is an operation diagram of the Wallerstone prism used in the pick-up optical element of the magneto-optical type as shown in FIG.

8 is a perspective view and a plan view of a compact optical element for optical pickup of a PC (Phase Change) type in a second embodiment according to the present invention.

* Explanation of symbols for main parts of the drawings

21, 71, 101: LD

22, 75, 105: LD submount

23, 74, 104: Si submount

24, 84, 113: right angle prism

27, 85, 114: reflection mirror

25, 89, 119: PBS

26, 88, 105, 117: CL

28, 86, 115: optical block 1

29, 87, 116: optical block 2

30: optical block 3 33: PD mount

32, 72, 102: sensor PD 34: laser beam path

35, 42, 62, 78, 199: laser beam

43: cylindrical lens

51, 61, 112: Swingarm

52: VCM 53: main optical element

55: reflection mirror 56, 66: disk

57, 64: objective lens 58: slider

59: suspension 60: spindle motor

65: driver

79, 93 Wallacestone Prism

73, 103: monitor PD

76, 106: right angle prism 1

77, 108: Light Angle Prism 2

81: PD cell for tracking 80: PD cell for RF signal

82: thermal barrier 91: s-polarization

92: p-polarized 100: Rf & TE signal PD cell

118: QWP 120: diffraction element

In the optical pickup small optical device according to the present invention for achieving the above object is formed by integrating the component on the substrate to have a height of 1 ~ 2mm including the substrate, the path of the laser beam optical information recording medium It is characterized in that it continues horizontally with respect to the surface of the.

In addition, according to the present invention, the optical pickup compact optical device connects an end portion of the substrate or forms the optical element thereon according to the weight of the optical element, and the laser is advanced horizontally by the optical element at the end portion thereof. A swing arm having a reflective mirror configured to redirect a beam by 90 degrees to send a laser beam toward the optical information recording medium, and positioned between the lower reflection mirror and the optical information recording medium, the lower reflection mirror and the optical information recording medium A slider positioned between and connected to the swing arm, and having an objective lens and a solid immersion lens attached thereto to focus the laser beam and to maintain a constant distance from the surface of the optical information recording medium, and the slider Near-field light including a suspension to fix the position to the lower portion of the swing arm It is characterized in that applied to the pickup system.

In addition, according to the present invention, a small optical element for optical pickup according to the weight of the optical element is connected to the end of the substrate or to form the optical element on the upper portion, and the end is horizontally advanced by the optical element A swing arm formed with a reflection mirror which redirects the path of the laser beam by 90 degrees to send the laser beam toward the optical information recording medium, and is positioned between the lower portion of the reflection mirror and the optical information recording medium, and focuses the laser beam by a driver. It is characterized in that it is applied to a general optical field (Far field) optical pickup system comprising an objective lens that is maintained at a constant distance from the surface of the optical information recording medium.

The present invention is characterized in that both of the case where the medium of the optical information recording medium is a magnetic recording medium and the case of a phase change recording medium.

The function of the present invention according to the above characteristics is to form an integrated optical component by integrating each component on the substrate in the form of the existing optical element sideways in the whole optical pickup system of the near-field method or the general optical field method 1 ~ It can be formed by limiting the height of the optical element to within 2mm, so that the size can be reduced, and when mounted on the portable terminal, a large amount of information can be stored on the optical information recording medium through the portable terminal, thereby exchanging media and transferring each other. Also, it can be used as a means for storing data such as PDA.

By using the point that the height of the optical element is high and the width is small compared to the height, each component is integrated on the substrate and manufactured in a compact form by dividing the existing optical element,

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

A preferred embodiment of an optical pickup compact optical element according to the present invention will be described with reference to the accompanying drawings.

2 is a perspective view and a perspective plan view of a miniature optical element for optical pickup according to the present invention.

As shown in Fig. 2, the optical element according to the present invention has a structure in which a conventional optical element is laid on its side.

A laser diode (LD) 21 and an LD submount 22 are attached onto the Si submount 23, and the light emitted from the light is reflected by a right angle prism 24.

The reflected light is reflected by the polarization beam splitter (PBS) 25 and proceeds to be collected by the collimation lens (CL) 26 to become parallel light, which is continuously reflected and reflected by the light reflection mirror 27 to the disk. Will proceed in the direction.

The optical system presented here omits the objective lens so that the objective lens is positioned under the light angle prism 2 (27) to collect light to the disk.

The optical blocks 1, 2, 3 (optical blocks) 28, 29, and 30 are for supporting the light angle prism 24, the PBS 25, and the reflecting mirror 27, respectively.

The light partially transmitted from the PBS 25 is incident on the monitor photo diode (PD) 31, thereby adjusting the light intensity of the LD 21.

On the other hand, the light reflected from the disk is returned to pass through the PBS (25) to enter the sensor PD 32 for RF and TE signals.

Where the identification number 33 is a PD mount for supporting the sensor PD 32 for detecting the optical signal, the identification number 35 represents a laser beam after being reflected by the reflection mirror 27 after becoming parallel light, Identification number 34 represents the path of this laser beam 35.

The device may further include other elements according to the type of recording medium. First, when recording using a phase change (PC) material, QWP (isolation) for isolating the light returned to the LD 21 may be used. A quarter wave plate can be used after CL (26).

In the case of using a magneto optical (MO) recording medium, a Wallaston prism is placed behind the PBS 25 and the optical block 1 (28) and in front of the sensor PD 32 to obtain a polarized signal. Can be used to position.

FIG. 3A shows a laser beam radiation pattern of a general LD, and FIG. 3B shows a radiation pattern of a laser beam corrected using a small cylindrical lens.

The configuration of the small optical element for optical pickup as shown in FIG. 2 is a case where beam shaping is not performed assuming that the radiation form of the laser beam is symmetrical, otherwise the laser beam is elliptical in shape. Prism-shaped beamforming prisms can be used to make them nearly circular.

However, in the pickup configuration on the premise of small size, beam shaping may be performed by attaching a small cylindrical lens in front of the LD as shown in FIG.

When the laser beam 42 is emitted from the LD 21, as shown in Fig. 3A, the upper, lower, left, and right radiation angles are different, which means that the laser beams in the X and Y axes are different in size. However, in FIG. 3B, the radial angles of the upper and lower sides are equalized using the cylindrical lens 43.

The small optical element for pickup thus manufactured is low in height, and thus can be applied as a small micro-drive pickup, and can be applied to both a general optical field and a near field.

Fig. 4 shows the structure of the entire system in which the small optical element as shown in Fig. 2 according to the present invention is located, and in particular the optical system in the near field method.

Here, the swing arm 51 has its rotation axis fixed to the voice coil motor (VCM) 52, and the main optical element 53 of the small optical element is placed on the rotation axis of the swing arm 51. .

This is to reduce the positional shift during the swinging of the swing arm 51 due to the weight of the optical element 53, that is, the inertia, but the swing arm 51 when the weight of the optical element 53 is light. It may be placed in the middle or at the end.

Then, the reflective mirror 55 is attached to the swing arm 51 to reflect the parallel laser beam 54 from the optical element 53, thereby changing the light propagation direction by 90 degrees. ) Light in the direction of.

As shown in FIG. 4, the near-field method includes a slider 58 having an objective lens (OL) 57 and a solid immersion lens (SIL) attached to the swing arm 51, and a suspension for fixing it to the swing arm 51 ( 59, so that the slider 58 is below the reflective mirror 55 on the swing arm 51.

In the case of the near-field method, it is difficult to actively adjust the focus, so the focus is adjusted by keeping the thicknesses of the air layers of the disk 56 and the slider 58 constant without using a focus servo. .

The identification number 60 here is a spindle motor for turning the disk 56.

FIG. 5A is a cross-sectional view showing a combination of an objective lens and a swing arm in the near field method, and FIG. 5B is a cross-sectional view showing a combination of an objective lens and a swing arm in the case of a general optical field method. to be.

As shown in Fig. 5B, the laser beam 62 traveling in parallel to the swing arm 61 is reflected by the prism 63 to be incident on the objective lens OL 64, and to this OL 64. An actuator 65 is attached to adjust the distance between the disk 66 and the OL 64 to focus the laser beam on the disk 66.

As described above, the present invention uses the point that the height of the existing optical element is high and the width is small compared to the height, thereby making the existing optical element smaller and smaller, thereby applying both the near-field method and the general optical field method. In addition, both magneto-optical and phase-transfer methods can be applied depending on the recording medium.

6 is a perspective view and a plan view of a miniature optical element for an optical pickup of a magneto-optical type according to a first embodiment according to the present invention.

As shown in Fig. 6, in the case of a magneto optical (MO) system, a Wallerston prism 79 is placed behind the PBS 1 89 and the optical block 1 86 to obtain a polarized signal. And it can be used in front of the sensor PD (72).

The small magneto-optical device of the magneto-optical type is based on the Si 71, the sensor PD 72, and the monitor PD 73 based on the Si submount 74 serving as the bottom of the pickup. and the LD 71 is attached to the LD submount 75 so as to integrate circuits for electrical connection.

The laser beam 78 traveling in a direction parallel to the Si submount 74 is reflected by the light angle prisms 1, 2 (76) and 77 to the PDs 72 and 73 embedded in the floor. Let's join.

The sensor PD 72 is an RF signal that is a signal by recording data of a disc, a track error (TE) signal for finding a recording area (land and groove) of the disc, that is, tracking, and a disc. And optical signals such as focus error (FE) signals to adjust the distance between the objective lens (for Far Field) or disk and SIL (Near Field) so that the laser beam is focused on the disk. Measure

In addition, the arrangement and shape of the sensor PD 72 are determined according to the pickup configuration. For example, in the near field method, one beam method is used instead of the three beam method, and since only one laser beam is used to obtain a tracking signal with one beam push-pull, two-track tracking type is used. The PD cell 81 and the RF signal PD cell 80 for reading the recording signal split by the Wallerston prism 79 are positioned to the left and right of the tracking PD cell 81 in the middle. Done.

In addition, the monitor PD 73 is for controlling the power of the laser, and the larger the size, the slower the response speed can be designed in consideration of the size and sensitivity.

In this case, when the LD 71 is attached to the Si submount 74, a trench-like structure capable of thermally blocking the LD 71 and the PD 72, 73 is formed by Si etching to form the thermal barrier 82. This prevents thermal noise caused by the LD 71 from entering the PDs 72 and 73.

Identification number 84 represents a light angle prism, 85 represents a reflection mirror, identification number 87 represents an optical block 2, and identification number 88 represents CL.

FIG. 7 illustrates the operation of the Wallerstone prism used in the magneto-optical pick-up optical element as shown in FIG. 6. The Wallerstone prism refracts p-polarized light and s-polarized light having different polarization components in different directions. The present invention is designed to detect a difference in polarization components of a recording signal whose polarization is changed by a disk.

When the s-polarized light 91 and the p-polarized light 92 are incident at the same time as shown in FIG. 7, the Wallerstone prism 93 detects the s-polarized light 91 and the p-polarized light 92 at the same time. The left and right separate the s-polarized light 91 and the p-polarized light 92. The intensity of light in these three directions is 1 (left): 2 (middle): 1 (right).

FIG. 8 shows a perspective view and a plan view of a compact optical element for optical pickup of a PC (Phase Change) type in a second embodiment according to the present invention.

As shown in Fig. 8, in the case of a phase change (PC) system, a quarter wave plate (QWP) for isolating light returned to LD can be used after CL.

That is, the PC method removes the Wallerstone prism used for the magneto-optical method as shown in FIG. 8 and attaches the QWP 118 to the reflection mirror 114 after the CL 117 to reflect the medium through the PBS 119. It is possible to block the laser beam so that the returned light is incident only in the PD (102, 103) direction.

In addition, a diffraction element (grating) 120 may be inserted into the light angle prism 113 on which the laser is first reflected, and a three-beam tracking method using +1 order and −1 order may be used. When the three beams are used in this way, the sensor PD 103 is composed of three Rf & TE signal PD cells 100 as shown in the plan view of FIG. All three cells can be used to obtain tracking and RF signals.

In addition, the above two pickups do not use the CL 117 and the sensor lens, respectively, but have a distance from the LD 101 to the CL 117 and also a distance from the PD 103 to the CL 117. It is manufactured so that one lens has two functions.

Identification number 104 is Si submount, identification number 105 is LD submount, identification numbers 106 and 108 are right angle prisms 1 and 2, identification numbers 115 and 116 are optical blocks 1 and 2 respectively, identification number 109 Denotes a laser beam and ID 112 denotes a swing arm.

As described above, the small optical device for optical pickup according to the present invention has the following effects.

The optical element is high and the width is small compared to the height, and each component is integrated into a substrate and manufactured in a compact form by dividing the existing optical element into a side shape. In this case, about 1GB of information can be stored in a disk through a portable terminal to exchange media and transfer each other, and can also be used as a data storage means such as a PDA.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (8)

Small optical element for optical pickup, characterized in that the component is formed by integrating the component to the substrate to have a height of 1 to 2 mm including the substrate, and the path of the laser beam continues horizontally with respect to the surface of the optical information recording medium. . The method of claim 1, The optical information recording medium is formed by connecting an end portion of the substrate or forming the optical element thereon according to the weight of the optical element, and changing the path of the laser beam horizontally advanced by the optical element at the end portion by 90 degrees. A swing arm having a reflection mirror configured to send a laser beam in a direction; A suspension positioned between the lower portion of the reflective mirror and the optical information recording medium and connected to the swing arm, and an objective lens and a solid immersion lens are attached to focus the laser beam, and a surface of the optical information recording medium. A slider for maintaining a constant interval; And And irradiating the optical information recording medium with a laser beam horizontally directed to the surface of the optical information recording medium by a near-field optical pickup system including a suspension for fixing the slider to be positioned below the swing arm. Compact optical element for optical pickup. The method of claim 1, The optical information recording medium is formed by connecting an end portion of the substrate or forming the optical element thereon according to the weight of the optical element, and changing the path of the laser beam horizontally advanced by the optical element at the end portion by 90 degrees. A swing arm having a reflection mirror configured to send a laser beam in a direction; A general optical field type light including an objective lens positioned between the reflecting mirror and the optical information recording medium, focusing the laser beam and maintaining a constant distance from the surface of the optical information recording medium by a driver. And a pickup system for irradiating an optical information recording medium with a laser beam traveling horizontally with respect to the surface of the optical information recording medium. The method of claim 1, When the optical information recording medium is a magnetic recording medium, each component of the optical element is An LD submount formed on the substrate and supporting a laser diode (LD) thereon; A polarization beam splitter (PBS) for separating and outputting the laser beam output from the LD according to polarization; A collimating lens (CL) for condensing the laser beam output from the PBS to produce parallel light and outputting the laser beam to the reflective mirror; A monitor photodetector integrated with the substrate and configured to enter a laser beam partially transmitted from the PBS and to adjust light intensity; A sensor photodetector integrated with the substrate and configured to detect a recording signal and a tracking error signal when light reflected from the optical information recording medium passes through the PBS; And a Wallerston prism formed on the substrate so as to be positioned between the PBS and the sensor photodetector, and refracting a laser beam in a different direction according to polarization to detect a polarization signal of the recording signal. Small optical device for optical pickup, characterized in that the. The method of claim 1, When the optical information recording medium is a phase change recording medium, each component of the optical element is An LD submount formed on the substrate and supporting a laser diode (LD) thereon; A polarization beam splitter (PBS) for separating and outputting the laser beam output from the LD according to polarization; A collimating lens (CL) for condensing the laser beam output from the PBS to produce parallel light and outputting the laser beam to the reflection mirror; A monitor photodetector integrated with the substrate and configured to enter a laser beam partially transmitted from the PBS and to adjust light intensity; A sensor photodetector integrated with the substrate and configured to detect a recording signal and a tracking error signal when light reflected from the optical information recording medium passes through the PBS; And a quarter wave plate (QWP) for isolating light returned to LD on the reflective mirror surface facing the CL. The method according to claim 4 or 5, Located between the LD and the PBS, and further comprises a cylindrical lens for processing a laser beam output from the LD, the optical pickup small optical element. The method according to claim 4 or 5, And the distance between the LD and CL and the distance between the monitor photodetector and CL is the same. The method according to claim 4 or 5, And a thermal barrier having a trench structure for blocking thermal noise between the LD and the photodetector on the substrate.