KR100446728B1 - Apparatus for near field optical recorder - Google Patents

Abstract

The present invention comprises a slider for mounting an opposing lens opposed to a surface of a disc, the near field optical recording and reproducing apparatus for recording or reproducing information by injecting near-field light onto the disk, the layer having the optical axes coinciding with each other. A main body having an objective lens mounted as a structure and the opposite lens; A first thin plate formed at a mounting position of the objective lens and coupled to the main body; A second thin plate coupled to the first thin plate on the opposite side of the main body to be laminated in a layered structure with a predetermined distance by the first thin plate and the space keeping means; A laser diode chip mounted on a surface of the second thin plate facing the first thin plate; A transmitter / receiver formed on a surface of the first thin plate facing the second thin plate, and configured to form a near field by injecting light emitted from the laser diode chip into the disc through the opposing lens; By presenting the structure of the slider configured to include, even when the light irradiating portion and the light receiving portion are both formed on the slider, the near field of the more advanced structure, which can protect the light transmitting and receiving portion from the heat generated in the light irradiation portion An optical recording and reproducing apparatus is provided.

Description

Near field optical recorder {APPARATUS FOR NEAR FIELD OPTICAL RECORDER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a near field optical recording and reproducing apparatus, and more particularly, to a heat shield structure in a slider mounted with an opposing lens and a light irradiating unit opposed to a surface of a recording medium.

An optical recording medium or a magneto-optical recording medium must have a small bit (or recording mark) size and a narrow track width to have a high density recording capacity. However, since the spot size of the light condensed on the recording medium to form a bit in the recording film of the recording medium is limited by the diffraction limit, there is a limit in improving the recording density.

In light of the trend of large-capacity information, new optical recording / reproducing methods are required to overcome the limitations of existing optical recording / reproducing methods. In recent years, research on near field recording / reproduction using near field, which is expected to significantly improve recording capacity, has been increasing.

The principle of near field optical recording and reproduction is as follows. Light entering the lens at an angle greater than or equal to the critical angle is totally reflected when traveling from a dense refractive index to a small one. At this time, due to total reflection of light, light of very small intensity exists on the surface of the lens, which is called an evanescent wave or dissipation wave. Using this evernet wave, it is possible to achieve high resolution, which is impossible because of the diffraction limit, which is the absolute limit of the resolution due to the diffraction phenomenon of light in the far-field. The near field optical recording and reproducing optical system totally reflects the light in the lens to generate an Evernet wave on the surface of the lens, and records and plays back by coupling the Evernet wave and the recording medium.

1 and 2 show a structure of a conventional near field optical recording and reproducing apparatus, in which FIG. 1 is a plan view and FIG. 2 is an enlarged cross-sectional view of a slider unit on which an opposing lens is mounted.

As shown in the drawing, the conventional near field optical recording and reproducing apparatus includes a swing arm 21 reciprocally rotatable with respect to a base, an actuator 23 providing a rotational driving force to the swing arm 21, and pneumatic pressure. And a slider 30 provided at an end of the swing arm 21 so as to scan the track of the optical disc 10 while being lifted with respect to the optical disc 10.

The slider 30 includes an objective lens 31 and an opposite lens 32 spaced apart from each other by a predetermined focal length, and a main body portion 33 for fixing the lens. Solid Immersion Lens (SIL) or Solid Immersion Mirror (SIM) is generally used.

2 illustrates an apparatus employing a refractive-type solid-impregnated lens as the opposing lens 32. The opposing lens 32 has a large incident angle at which light emitted from a light irradiator (not shown) and a transmitter / receiver 40 is large. The optical disk 10 is focused. As a result, the size of the light spot formed on the optical disc 10 can be reduced.

In general, the light irradiation unit uses a semiconductor laser, and the transmission and reception unit 40 includes a light detector and an optical path converting means. At this time, the optical path converting means directs the light emitted from the semiconductor laser toward the reflective mirror 34 and converts the traveling path of the light so that the light reflected from the optical disc 10 is returned to the photodetector.

The transmitter / receiver 40 irradiates laser light having a suitable diameter to the objective lens 31, and the reflection mirror 34 reflects the light incident from the transmitter / receiver 40 toward the objective lens 33. The objective lens 31 focuses incident light on the opposing lens 32, and the opposing lens 32 forms a near field on the optical disc 10.

On the other hand, as the distance between the light irradiating part and the transmitting and receiving part 40 and the opposing lens 32 is spaced apart, the possibility of an error due to the length of the path through which the light passes and the difficulty of the installation work of the optical system may be problematic. In order to solve this problem, it is possible to assume a structure in which both the light irradiation part and the light receiving part are formed on the slider.

However, in this structure, since the semiconductor laser used in the light irradiation part has a larger amount of heat emitted at higher output, there is a concern that the performance of the transmitting and receiving part formed adjacent to the light irradiation part may be deteriorated. It is necessary to seek.

The present invention solves the above problems, and even when the light irradiation part and the light receiving part have a structure formed on the slider, the near field of the more advanced structure, which can protect the light receiving part from heat generated in the light irradiation part. It is an object to provide an optical recording and reproducing apparatus.

1 and 2 show the structure of a conventional near field optical recording and reproducing apparatus,

1 is a plan view

2 is an enlarged cross-sectional view of a slider unit on which an opposing lens is mounted;

3 to 6 show the structure of the near field optical recording and reproducing apparatus according to the present invention.

3 is a plan view

4 is a perspective view of the slider portion seen from the upper side of the second thin plate;

5 is a side view of the slider portion

6 is a cross-sectional view showing the structure of a reflective orthopedic prism;

** Explanation of symbols for main parts of drawings **

10 disc 21 swing arm

100: slider 110: main body

111: objective lens 112: opposing lens

120: first thin plate 121: through hole

130: second thin plate 131: laser diode chip

140: interval maintaining means 200: transmitter and receiver

210: beam splitter 211: exploded surface

220: collimating lens 230: reflective orthopedic prism

240: wave plate 250: light angle prism

260: photodiode IC. 300: thermal cutoff means

310: thermal barrier

In order to achieve the above object, the present invention comprises a slider for mounting an opposing lens that is opposed to a surface of a disc, the near field optical recording and reproducing for recording or reproducing information by injecting near field light onto the disc. An apparatus comprising: an objective lens mounted as a layered structure such that the optical axes coincide with each other, and a main body having the opposing lens; A first thin plate formed at a mounting position of the objective lens and coupled to the main body; A second thin plate coupled to the first thin plate on the opposite side of the main body to be laminated in a layered structure with a predetermined distance by the first thin plate and the space keeping means; A laser diode chip mounted on a surface of the second thin plate facing the first thin plate; A transmitter / receiver formed on a surface of the first thin plate facing the second thin plate, and configured to form a near field by injecting light emitted from the laser diode chip into the disc through the opposing lens; The present invention provides a near field optical recording and reproducing apparatus.

The slider may further include heat blocking means formed between the laser diode chip and the light receiving unit; It is preferable to provide additionally.

In addition, the heat shield means is preferably a heat shield wall formed of a resin on the surface of the first thin plate facing the second thin plate.

The transmitter / receiver includes: a beam splitter mounted to have an exploded surface for reflecting light emitted from the laser diode chip; A collimating lens mounted to the through-hole side to coincide with the optical axis of the light reflected or transmitted through the beam splitter; Reflecting means mounted to reflect light transmitted through the collimating lens toward the objective lens through the through hole; A wave plate mounted opposite the through hole of the beam splitter; A light angle prism for reflecting light transmitted through the wave plate; A photodiode IC mounted to irradiate the light reflected from the light angle prism; It is preferable to comprise.

In addition, either of the impregnated lens (SIL: Solid Immersion Lens) or the solid impregnated mirror (SIM) may be used for the opposing lens.

In addition, the reflecting means includes a refractive surface for refracting the incident light transmitted through the collimating lens at a predetermined angle; An optional transmission surface that totally reflects light incident from the refracting surface and combats light incident vertically; A total reflection surface for irradiating light to the opposing lens by totally reflecting the light totally reflected at the selective transmission surface and inciding it perpendicularly to the selective transmission surface; It is preferable that it is a reflection type shaping | molding prism comprised including.

Further, the first thin plate and the second thin plate are preferably composed of a silicon wafer.

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

3 to 6 show the structure of the near field optical recording and reproducing apparatus according to the present invention. Is a cross-sectional view showing the structure of a reflective orthopedic prism.

As shown, the near field optical recording and reproducing apparatus according to the present invention comprises a slider 100 for mounting an opposing lens 112 opposed to the surface of the disk 10 in close proximity.

Here, the slider 100 includes a main body having an objective lens 111 and an opposing lens 112 mounted as a layered structure such that the optical axes coincide with each other; A first thin plate 120 formed at a mounting position of the objective lens 111 and coupled to the main body 110; A second thin plate 130 coupled to the main body 110 of the first thin plate 120 at a predetermined interval by the first thin plate 120 and the space keeping means 140 at a predetermined interval; A laser diode chip 131 mounted on a surface of the second thin plate 130 that faces the first thin plate 120; Transmitting and receiving part which is formed on the surface of the first thin plate 120 facing the second thin plate 130, the light emitted from the laser diode chip 131 incident to the disk through the opposing lens 112 to form a near field ( 200); It is configured to include.

That is, in the near field optical recording / reproducing apparatus according to the present invention, the light irradiation section and the light receiving section have a structure in which both the light irradiation section and the light receiving section are formed on the slider on which the opposing lens is mounted, and the first thin plate 120 and the light receiving section on which the light irradiation section is mounted. Since the second thin plate 130 on which the 200 is mounted has a structure in which the second thin plate 130 is spatially separated, the performance of the transmitting and receiving unit can be prevented from being degraded by conduction through the thin plate of heat generated from the light irradiation unit.

In addition, the slider 100 includes a heat shield means 300 formed between the laser diode chip 131 and the light transmitting and receiving unit 200; It may be provided additionally.

Here, the heat blocking means 300 may be implemented by a heat blocking wall 310 formed of a resin, as shown in FIG. This may prevent heat generated in the laser diode chip 122 from being transmitted to the transmitter / receiver 200 by direct radiation.

The transmitter / receiver 200 may have any structure in which light emitted from the laser diode chip 131 is incident to the disk 10 through the opposing lens 112 to form a near field, but the slider 100 having a fine structure may be used. It is preferable to take the following configuration from the viewpoint of being formed on the).

That is, in the near field optical recording and reproducing apparatus according to the present invention, the transmitting / receiving unit 200 includes a beam splitter 210 mounted to have a decomposition surface 211 reflecting light emitted from the laser diode chip 122; A collimating lens 220 mounted to the through-hole 121 to coincide with the optical axis of the light reflected or transmitted through the beam splitter 210; Reflecting means 230 mounted to reflect the light passing through the collimating lens 220 toward the objective lens 111 through the through hole 121; A wave plate 240 mounted on the opposite side of the through hole 121 of the beam splitter 210; A light angle prism 250 for reflecting light transmitted through the wave plate 240; Photodiode IC mounted to irradiate the light reflected from the light angle prism 250. 260; It is configured to include.

In addition, in the present invention, all the elements constituting the optical system are mounted on the first thin plate 120 and the second thin plate 130 in the form of very small elements (chips), and the thin plates 120 and 130 are placed on the slider body 110. It is characterized by being bonded as a layered structure.

Here, the thin plates 120 and 130 may be formed of a metal material or the like, but it is more preferable to use a silicon wafer in view of processability such as grooves or through holes for forming a circuit by printing and positioning elements. Do.

Therefore, by printing the circuit on the surface of the silicon wafer, forming a groove for positioning the optical element, and then combining the optical elements as shown in the drawing, a slitter having an ultra-compact and ultra-light optical system can be formed by a simple process. It can be formed.

In addition, in fabricating the two thin plates 120 and 130 on which the optical elements are mounted as a layered structure as described above, an optical system is formed on the surface of each silicon wafer once, and the two silicon wafers are predetermined by the space keeping means 140. After joining at intervals of, the ease of mass production can be ensured by cutting to a predetermined size.

The opposing lens 112 may use either a solid immersion lens (SIL) or a solid immersion mirror (SIM).

The reflecting means 230 includes a refractive surface 231a for refracting the incident light transmitted through the collimating lens 220 at a predetermined angle; An optional transmission surface 231b which totally reflects the light incident on the refracting surface 231a and causes the light incident on the vertical surface to be overkill; A total reflection surface 231c for irradiating light to the opposing lens 112 by totally reflecting the light totally reflected from the selective transmission surface 231b and incident perpendicularly to the selective transmission surface 231b; It is preferable that it is the reflective shaping prism 231 comprised.

The light incident from the collimating lens 220 causes the light to be refracted at a predetermined angle while passing through the refractive surface 231a, is totally reflected on the selective transmission surface 231b, and then totally reflected on the total reflection surface 231c, thereby again selecting the transparent transmission surface 231b. By being incident perpendicularly to), the selective transmission surface 231b is irradiated with the opposing lens 112.

To this end, a reflection coating film should be formed on the total reflection surface 231c, and a reflection coating film should not be formed on the refractive surface 231a and the selective transmission surface 231b.

On the other hand, as shown in FIG. 6, when the refractive index of the reflective shaping prism 231 is n, and the angle between the refractive surface 231a and the selective transmission surface 231b is θ, the reflective prism ( The following relation holds between the diameter Hi of the light incident on the refracting surface 231a and the diameter Ho of the light reflected from the total reflection surface 231c and transmitted through the selective transmission surface 231b.

Therefore, by appropriately adjusting the refractive index n of the reflective shaping prism 231 and the angle θ formed between the refractive surface 231a and the selective transmission surface 231b, the light incident on the reflective prism 231 The ratio of the diameter Hi and the diameter Ho of the reflected and transmitted light can be adjusted.

Using this principle, the height of the reflecting means 230 can be reduced even under the premise of satisfying the condition that the light incident from the collimating lens 220 should be reflected at right angles and irradiated toward the opposite lens 112. Ultimately, the thickness of the slider 100 may be reduced.

In addition, basically, the light irradiated from the laser diode chip 131 has an elliptical cross section as laser light. When the light passes through the reflective prism 231 having a structure in which the refractive index (n) and the angle (θ) are properly adjusted. The light is converted into light having a circular cross section.

That is, when the reflective shaping prism 231 having the above structure is mounted on the slider 100, the effect of beam shaping can be obtained.

The operation of the near field optical recording and reproducing apparatus according to the present invention will be described below.

The light irradiated from the laser diode chip 131 is reflected at the decomposition plane 211 of the beam splitter 210, is converted into parallel light while passing through the collimating lens 220, and is shaped by the reflective shaping prism 231. And it is reflected to face the through-hole 121.

At this time, the heat generated from the laser diode chip 131 is blocked by the heat shield means 300 implemented by the double structure of the thin plate (120,130) and the heat shield wall 310 of the present invention, Excessive delivery to the 200) side is prevented.

The light collected by the objective lens 111 and the opposing lens 112 formed below the through hole 121 reproduces or records a signal on a disk (not shown), and then, the opposing lens 112 and the objective lens 111 The light is collected while passing through the collimation lens 220 through the path of the reflective shaping prism 231.

Such light is transmitted straight through the decomposition surface 211 of the beam splitter 210 as it is, causing the deformation of the polarization deflection pattern while passing through the wave plate 240, and is reflected by the light angle prism 250, The photodiode IC transmits a signal.

The present invention provides a near field optical recording / reproducing apparatus having a more advanced structure that can protect the transmitting / receiving unit from heat generated in the light irradiation unit even when both the light irradiation unit and the light receiving unit are formed on the slider.

Claims (8)

A slider comprising a slider body and a mounting thin plate tightly coupled to an upper surface of the slider body, an objective lens and an opposing lens mounted on the slider body, a laser diode chip mounted on the thin plate to irradiate light onto the objective lens, A near field optical recording and reproducing apparatus, comprising: a transmitting / receiving unit mounted on a thin plate to inject light irradiated from the laser diode chip onto a disk through the objective lens and an opposite lens to form a near field; On the opposite side of the main body of the mounting thin plate is provided with a heat dissipation thin plate cover coupled in a layered structure at predetermined intervals by the mounting thin plate and the interval maintaining means, so that the transmitting and receiving unit Near field optical recording and reproducing apparatus, characterized in that the heat generated from the laser diode chip is installed to be discharged to the outside through the heat radiation thin plate cover. The method of claim 1, The slider is A heat shield means formed between the laser diode chip and the light transmitting and receiving portion and connecting the mounting thin plate and the heat dissipating thin plate cover; Near field optical recording and reproducing apparatus further comprising. The method of claim 2, The thermal cutoff means And a heat shielding wall formed by a resin so as to connect the mounting thin plate and the heat dissipating thin plate cover between the mounting thin plate and the heat dissipating thin plate cover. The method of claim 1, The transmitter and receiver A beam splitter mounted to have an exploded surface for reflecting light irradiated from the laser diode chip; A collimating lens mounted to the through-hole side to coincide with the optical axis of the light reflected or transmitted through the beam splitter; Reflecting means mounted to reflect light transmitted through the collimating lens toward the objective lens through the through hole; A wave plate mounted opposite the through hole of the beam splitter; A light angle prism for reflecting light transmitted through the wave plate; A photodiode IC mounted to irradiate the light reflected from the light angle prism; Near field optical recording and reproducing apparatus, characterized in that configured to include. The method according to any one of claims 1 to 4, And said opposing lens is a solid-impregnated lens. The method according to any one of claims 1 to 4, And said opposing lens is a solid impregnation mirror. The method of claim 4, wherein The reflecting means A refracting surface that transmits the light passing through the collimating lens and refracted at a predetermined angle; An optional transmission surface that totally reflects light incident from the refracting surface and combats light incident vertically; A total reflection surface for irradiating light to the opposing lens by totally reflecting the light totally reflected at the selective transmission surface and inciding it perpendicularly to the selective transmission surface; A near field optical recording and reproducing apparatus, characterized in that it comprises a reflective orthopedic prism. The method according to any one of claims 1 to 4, And the first thin plate and the second thin plate are silicon wafers.