JP2003141768A - Optical probe and optical pickup - Google Patents

Abstract

(57) [PROBLEMS] To provide a light emitting aperture that is hardly damaged, has a small light emitting aperture with high accuracy and high reproducibility, and performs a higher-speed tracking operation. A surface which is formed of the same material as a substrate made of a high refractive index material, has a tapered tapered surface on an outer wall, and faces a protruding portion having a light emitting portion having an elongated shape at a tip end. Is provided with a microlens 4 formed of the same material as that of the substrate 2 to prevent light incident on the microlens 4 from being reflected at the boundary between the microlens 4 and the substrate 2 and to utilize the incident light effectively. This incident light is passed through a micro lens 4
The light is condensed on the light emitting unit 5 to realize a very small light spot on the light emitting unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical probe for generating near-field light, an optical element for an optical pickup, and an optical pickup, and more particularly to increasing the recording density of an optical recording medium.

[0002]

2. Description of the Related Art Optical recording media typified by CDs and DVDs have been advancing toward high density and high density. As described above, in order to increase the density of the optical recording medium, it is necessary to shorten the wavelength λ of the incident light and increase the numerical aperture of the lens to miniaturize the recording bits of the optical recording medium. However, there is a limit to increase the resolution of light due to the diffraction limit of light, and it is impossible to miniaturize the recording bit of the optical recording medium beyond the diffraction limit and read the miniaturized recording bit without crosstalk.

An optical probe using near-field light is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-171380 as one of the solutions for miniaturizing the recording bit beyond the light diffraction limit. The optical probe shown in JP-A-2000-171380,
A rectangular light entrance opening is provided on one surface of the silicon substrate, and a light exit opening that collects and outputs the light incident from the light entrance opening is provided on the surface opposite to the light entrance opening. A guide wall is formed between the exit openings so that the cross section of the plane orthogonal to the light entrance opening is gradually smaller. The light exit opening is a one-dimensional rectangular opening with multiple light-shielding members on the long side. A plurality of apertures are formed at substantially equal intervals in the direction to form a plurality of apertures, and the slits are formed to reduce the weight and size of the optical probe and enable highly accurate tracking control.

In this optical probe, it is necessary to set the dimension of the short side of the rectangular shape on the light emission opening side to several tens of nm. When manufacturing this optical probe, a SiO ₂ layer formed on the surface and the back surface of the Si substrate by oxidizing the surfaces of the silicon substrate, by Rizogurafi from one SiO ₂ layer side such as surface,
A mask pattern of a resist film for forming the light entrance opening and the guide wall is formed. Anisotropic etching is performed from the mask pattern side to the back surface to form the light incident opening and the guide wall. A protective material is formed from the front side on the portion formed by this etching process, and a mask pattern made of a resist film for forming a light emission opening is formed on the back side using, for example, an electron beam drawing apparatus, and this mask pattern is formed. For example, the removal process is performed by using a fluoric acid buffer solution, the resist film is removed, and the protective material is removed to form the light emission openings arranged in a one-dimensional direction.

However, the thickness of the silicon substrate varies by several tens of μm between the substrates. The etching speed also greatly changes depending on the amount of silicon dissolved in the etching liquid, the amount of oxygen dissolved in the etching liquid, the delicate temperature, and the like. Therefore, from the etching speed measured in advance and the thickness of the silicon substrate, several tens of nm
It is very difficult in practice to stop the etching so that the opening size is formed.

Further, since a thick edge is formed around the small light emitting opening, the light emitting opening cannot be brought close to the recording medium up to a distance of several tens of nm. Then, the edge is removed. However, since the thickness of the portion having the light emission opening at this time is about 10 μm, the edge is very likely to be damaged during or after the removal.

The present invention solves the above disadvantages, the light emitting aperture is not easily damaged, has a fine light emitting aperture with high accuracy and high reproducibility, and is capable of performing a higher-speed tracking operation. An object of the present invention is to provide an optical pickup device capable of performing more accurate tracking control.

[0008]

An optical probe according to the present invention comprises a substrate made of a high refractive index material, a substrate made of the same material as the substrate, an outer wall having a tapered surface, and an elongated tip. It is characterized in that it has a protrusion having a light emitting portion in a shape and a condenser lens made of the same material as the substrate on a surface of the substrate facing the protrusion.

It is possible to divide the light emitting portion into slits by disposing a plurality of light shielding portions on the light emitting portion provided at the tip of the protrusion at substantially equal intervals in the long side direction of the elongated shape. desirable.

Further, it is preferable to provide a reinforcing member on the outer peripheral portion of the condenser lens or to provide a transparent substrate on the condenser lens side.

Further, when the refractive index of the condenser lens, the substrate and the protrusion is n and the wavelength of the light incident on the condenser lens is λ, the long side of the elongated light emitting portion provided at the tip of the protrusion. Of the length a and the length b of the short side are a ≧ (λ / 2n), b <(λ
The shape of the light emitting portion may be determined so as to satisfy the condition of / 2n).

An optical pickup according to the present invention is an optical pickup having the above-mentioned optical probe, wherein the light emitted from the optical system is deflected between an optical system for emitting the recording / reproducing light and the optical probe. It has a light deflecting means for scanning in the long side direction of the elongated light emitting part.

A galvanometer mirror, a rotary polygon mirror, an acousto-optic deflector or an electro-optic deflector may be used as the light deflecting means.

Further, the electro-optical deflector is composed of a cubic electro-optical crystal, and an electrode is formed parallel to the light transmitting direction, and the width of the electrode is formed in a shape changing along the light transmitting direction. It is desirable that

Further, as an electro-optic crystal, LN (LiN
It is preferable to use a bO ₃ ) crystal and determine the shape of the electrode so that an electric field is applied parallel to the optical axis of the LN crystal.

Further, it is preferable to use a domain inversion type electro-optical crystal as the electro-optical crystal.

Further, it is desirable that the light incident on the electro-optic crystal be linearly polarized light in a direction parallel to the optical axis.

Further, in the optical pickup of the present invention, the optical probe is provided below the tip of the arm, and the optical system, the optical deflecting means, and the focusing means for changing the optical path of the light from the optical deflecting means to enter the optical probe. It is characterized by being installed on the upper part of.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of an optical probe of the present invention, (a) is a front view, (b) is a sectional view, and (c) is a rear view. As shown in the figure, the optical probe 1 includes a substrate 2 formed of a high refractive index material, for example, a Si material, and a protrusion 3 formed of the same material as the substrate 2 and provided on one surface of the substrate 1. The microlens 4 is formed of the same material as the substrate 2 and is provided on the surface of the substrate 2 facing the protrusion 3 and condenses light. As shown in the perspective view of FIG. 2, the protrusion 3 is formed in a truncated pyramid shape having a tapered side surface with a tapered tip, and an elongated light emitting portion at the apex of the truncated pyramid shape. Have 5. The long side of the elongated light emitting section 5 is longer than the wavelength of the laser light, and the short side of the elongated light emitting section 5 is formed to have a wavelength of several tens of nanometers or less, thereby generating near-field light and propagating light near the light emitting section 5. Let A metal light-shielding film 6 is provided on the surface of the substrate 2 on which the protrusion 3 is provided and on the side surface of the protrusion 3. The metal light-shielding film 6 is formed of, for example, Al, Au, or the like, and is formed by a thin film forming technique such as vapor deposition to a thickness that does not allow light to pass therethrough. For example, when the metal light-shielding film 6 is formed of an Al material, it is formed with a film thickness of about 30 nm or more.

An optical system 7 of an optical pickup using this optical probe 1 has a semiconductor laser element (hereinafter referred to as LD) 8 as a laser light source, a collimator lens 9a and a beam splitter 10 as shown in the configuration diagram of FIG. And a collimator lens 9b and a photodetecting device (hereinafter referred to as PD) 11, and a deflector 12 between the beam splitter 10 of the optical system 7 and the optical probe 1. The deflector 12 is composed of, for example, a galvanometer mirror 13 which is swung by a motor.

When information is recorded on the recording medium 14 or information recorded on the recording medium 14 is read by the optical system 7 of the optical pickup, the laser beam emitted from the LD 8 is collimated by the collimator lens 9a and becomes a beam. Splitter 1
It is reflected at a right angle of 0 and is reflected by the galvano mirror 13. The laser light reflected by the galvanometer mirror 13 enters the microlens 4 of the optical probe 1, passes through the substrate 2, and is focused on the light emitting portion 5 provided at the tip of the protrusion 3. The microlens 4 of the optical probe 1 that passes the laser beam focused on the light emitting portion 5, the substrate 2 and the protrusion 3 are made of the same high refractive index material, for example, Si having a refractive index of about 3.7 at 750 nm to 850 nm.
Since it is made of a material, it is possible to prevent the laser light incident on the microlens 4 from being reflected at the boundary between the microlens 4 and the substrate 2 and at the boundary between the substrate 2 and the protrusion 3.
The light incident on the optical probe 1 can be efficiently used. Further, the light incident on the microlens 4 of the optical probe 1 is scattered by the metal light-shielding film 6 and is condensed so that the light intensity at the light emitting portion 5 of the protrusion 3 becomes large, and the light is emitted in the vicinity of the light emitting portion 5. Information can be efficiently recorded or reproduced on the recording medium 14 by generating near-field light. Moreover, the light other than the light generated from the tip of the protrusion 3 can be blocked by the metal light shielding film 6 to improve the S / N of the read signal.

The laser light incident on the optical probe 1 is transmitted to the light emitting portion 5 provided at the apex of the protrusion 3 while the direction of reflecting the laser light is periodically changed by oscillating the galvanometer mirror 13. Scanning is performed in the direction of the long side of the light emitting unit 5.

Tracking error detection and tracking actuation are one of the processes for recording and reproducing information on the recording medium 14 by the optical system 7 of the optical pickup. On the recording medium 14, there is a land groove as a guide groove for guiding the track to each track except for the ROM type in which writing is not possible.
A so-called beam wobbling operation is performed by the galvano mirror 13 so that the position of the emitted light is swung with a width smaller than the track width. Then, when the emitted light hits the land or groove of the recording medium 14, and at that time, the PD 1 is reflected from the recording medium 14 and passes through the galvanometer mirror 13, the beam splitter 10, and the collimating lens 9b.
The deviation between the center position of the wobbling width of the emitted light and the center position of the track can be detected from the intensity of the reflected light incident on 2, and so-called track error detection can be performed.
Further, from this value, the galvano mirror 13 can be controlled by the control circuit from the PD 12 to the galvano mirror 13 so that the center position of the oscillation width of the emitted light coincides with the center position of the track.

When recording or reproducing on the recording medium 14, the galvano mirror 13 is swung to change the direction in which the laser light is reflected, and the light emission provided at the apex of the projection 3 of the optical probe 1 is changed. By scanning in the long side direction of the unit 5, recording or reproduction can be performed on a plurality of tracks of the recording medium 14. That is, in order to reduce the gap between the recording medium 14 and the optical probe 1, the optical probe 1
The recording medium 14 may be contact-slipped. In this case, from the viewpoint of friction and wear, the recording medium 1
The rotation speed of 4 should be slow. In this way, the recording medium 14
If the rotation speed of is slowed down, the recording / playback speed will slow down. On the other hand, since the long side of the light emitting portion 5 of the optical probe 1 has a length of a plurality of tracks, the long side of the light emitting portion 5 is set to the track 15 of the recording medium 14 as shown in FIG.
By positioning the optical probe 1 on the recording medium 14 via the suspension 16 and oscillating the beam for recording and reproducing, recording or reproducing can be performed on a plurality of tracks 15, The recording / reproducing speed can be substantially improved. In particular, when the tracking operation is performed, it is sufficient that the light emitting portion 5 has a dimension of two tracks in the long side direction.

Further, by making the light emitting portion 4 at the apex of the protrusion 3 of the optical probe 1 into a so-called elongated shape such as an oval shape or a rectangular shape, a substantially elliptical beam spot generated by inter-mode interference is formed. A small spot can be realized also in the major axis direction, that is, in the direction parallel to the polarization direction of incident light. That is, in the optical probe 1, the small spot and high efficiency are achieved at the same time by utilizing the inter-mode interference effect. However, when the shape of the light emitting portion 5 at the apex of the protrusion 3 is a square shape, a circular shape, or a similar shape, the shape of the beam spot generated by the inter-mode interference becomes an elliptical shape. That is, the beam spot diameter becomes small in the direction perpendicular to the polarization direction of the incident light, and high resolution exceeding the diffraction limit can be achieved, but in the direction parallel to the polarization direction of the incident light. The beam spot diameter was reduced to about half a wavelength, which made it difficult to achieve high resolution. On the other hand, the shape of the light emitting portion 5 at the apex of the protrusion 3 is a rectangle in which the direction parallel to the polarization direction of the incident light is the short side and the direction perpendicular to the polarization direction of the incident light is the long side. With the shape, the light is confined by the short side of the light emitting portion 5 in the direction parallel to the polarization direction of the incident light, which has been difficult to be made into a small spot, and the light is confined in the direction parallel to the polarization direction of the incident light. On the other hand, it is possible to reduce the spot size of the beam spot, and it is possible to achieve higher resolution and higher efficiency.

Specifically, the shape of the light emitting portion 5 of the protrusion 3 is such that the wavelength of the laser light incident on the optical probe 1 is λ, and the refractive indexes of the microlens 4, the substrate 2 and the protrusion 3 are n. Then, the length a of the long side needs to be in the range of a ≧ λ / 2n, that is, the length a of the long side needs to be equal to or larger than the cutoff diameter (λ / 2n) of the lowest order mode. In addition, the length b of the short side needs to satisfy a> b. Specifically, in the projection 3 made of silicon (refractive index n = 3.6), when the wavelength λ is 780 nm, a> 108 nm. If the length a of the long side is set to be equal to or larger than the cutoff diameter (λ / 2n) of the lowest order mode, the length b of the short side is
It doesn't matter how much or how small it is.

Further, a micro lens 4 having a high numerical aperture for obtaining a small light spot diameter, for example, a solid immersion lens (Solid I
mmersion Lens, hereinafter referred to as SIL) may be used. For example, using light with a wavelength λ of 780 nm in vacuum, S
The numerical aperture of the microlens 4 made of IL is 1 and the projection 3 is
Supposing that the refractive index n of Si for forming is 3.7, it depends on the conditions such as the incident wavefront. However, considering the conditions of the wavefront that is actually obtained, the microlens 4 made of SIL causes the tip of the protrusion 3 to reach the tip. The beam diameter of 1 / e ² of the focused peak value is about 170 nm, and the beam diameter of half the peak value is about 100 nm. By setting the length b of the short side of the light emitting portion 5 of the protrusion 3 to several tens nm, for example, 50 nm, the size of the spot is limited by the length b of the short side, and the recording density can be further improved. .

Since the microlens 4, the substrate 2 and the protrusion 3 are made of Si which is a high refractive index material, the wavelength of light on the microlens 4, the substrate 2 and the protrusion 3 is the same as that of the microlens 4. It is shorter than when glass is used. Specifically, since the refractive index of glass is about 1.5, the wavelength in Si is 0.4 times that of glass. For example, light having a wavelength of 750 nm in vacuum becomes about 200 nm in Si. In this way, the wavelength of light is shortened in the microlens 4, the substrate 2 and the protrusion 3, so that the spot size is 0.4 times as large as when glass is used as the microlens 4, and higher density recording is realized. can do.

Further, as shown in FIG. 5, by providing the reinforcing portion 17 on the outer peripheral portion of the substrate 2 of the optical probe 1 on the microlens 4 side, the rigidity of the optical probe 1 can be increased and the microlens 4 can be provided. Can be easily manufactured.

A method of manufacturing the optical probe 1 will be described with reference to the process chart of FIG. First, as shown in FIG. 6A, a SiO ₂ layer 22 having a thickness of about 1 μm and a single crystal Si layer 23 having a thickness of about 5 to 10 μm are formed on a single crystal Si substrate 21 having a thickness of several 100 μm. So-called SOI substrates 20 that are stacked
To use. The refractive index of the single-crystal Si layer 23 has a wavelength λ =
The refractive index at 780 nm is very high, n = 3.7. Also, 5
A thickness of about μm shows a transmittance of about 40%. As shown in (b), a protrusion-shaped resin 24 is formed on the portion of the single crystal Si layer 23 where the protrusion 3 is to be formed, using photoresist or the like. Using the protrusion-shaped resin 24 as a mask, (c)
As shown in, the protrusion 3 is formed on the single crystal Si layer 23. Next, as shown in (d), a metal film 25 is deposited on the surfaces of the single crystal Si layer 23 and the protrusions 3. Then, as shown in (e), the metal film 25 at the tip of the protrusion 3 is formed by FIB.
Alternatively, the single crystal Si layer 2 is removed by chemical mechanical polishing or the like.
A metal light-shielding film 6 is formed on the surface of 3 and the side surface of the protrusion 3.
Next, as shown in (f), the central portion of the single crystal Si substrate 21 and the SiO ₂ layer 22 corresponding to the portion where the protrusion 3 is formed is removed, and the exposed protrusion 3 of the single crystal Si layer 23 is removed. Apply a photosensitive material (resist) to the position corresponding to. The thickness of the photosensitive material to be applied depends on the height of the microlens 4 formed on the single crystal Si layer 23, the etching rate of the Si material that is etched later using the photosensitive material as a mask, and the etching rate of the photosensitive material. Set by the ratio (selection ratio). For example, when the etching rates of both are equal (selection ratio 1), the height of the photosensitive material is made equal to the height of the microlens 4 to be formed. When the etching rate of the Si material is twice as high as the etching rate of the photosensitive material (selection ratio 2), the height of the photosensitive material may be 1/2 of the height of the microlens 4. As this photosensitive material,
A photoresist or a photosensitive dry film used in ordinary semiconductor manufacturing is used. Specifically, OFP
R-800 (positive resist), OMR-85 (negative resist) or the like may be used. The shape of the photographic mask used in the photolithography process changes depending on the selection of the positive type or negative type resist, but the basic forming procedure does not change. When a positive resist is used as the photosensitive material, the photosensitive material is exposed to light through a mask (photomask) formed with a pattern equivalent to the diameter of the microlens 4 on the photosensitive material. After that, develop. By this development, a pattern resin having a diameter of the microlens remains on the single crystal Si layer 23. Heat and pressure are applied to the remaining pattern resin, and due to the effects of gravity and surface tension,
As shown in (g), the convex lens-shaped resin 26 is formed. The temperature and pressure applied here vary depending on the shape of the pattern resin, but the temperature may be selected within the range of 200 to 400 ° C. and the pressure within the range of 1 to 10 atmospheric pressure. This formed convex lens-shaped resin 2
The single crystal Si layer 23 is etched (anisotropically etched) in the vertical direction by using 6 as a mask to produce the microlens 4 as shown in (h). As a means for this etching, dry etching which is usually used in a semiconductor manufacturing process can be used. Specifically, the reactive ion etching method (RIE) and the electron cyclotron resonance etching method (ECR) are used. The gas used for dry etching is selected depending on the substrate material. For example, when the substrate material is Si, CF ₄ , CHE _3, SF ₆ or the like is used. Further, a gas such as N ₂ , O ₂ or Ar may be mixed with the above etch gas to adjust the etching rate and the selectivity.

Since the microlens 4 can be arranged close to the protrusion 3 in this manner, the numerical aperture NA can be increased, and the light utilization efficiency and the recording density can be improved.

As a method of forming a photoresist pattern for manufacturing the microlens 4, in addition to the reflow method described here, a so-called halftone mask pattern photomask 24a as shown in FIG. 7 is used. You can use it. Furthermore, the microlens 4 does not necessarily have to be a spherical lens, and may be an aspherical lens or an elliptical lens.

Further, as shown in FIG. 8, a plurality of light-shielding portions 1 are arranged at regular intervals of, for example, about 50 nm in the long side direction of the light emitting portion 5 provided at the apex of the protrusion 3 of the optical probe 1.
8 may be provided, and the light emitting portion 5 may be divided and arranged in a plurality of minute regions. The interval between the plurality of light shielding portions 18 is equal to the protrusion 3
It is determined by the resist pattern formed at the apex portion of, and its dimensional accuracy can be made extremely high.

In this case, the laser light which is incident on the optical probe 1 and is scanned in the long side direction of the light emitting section 5 is sequentially emitted from the minute area of the light emitting section 5 in the long side direction to the recording medium 14,
High-speed recording and reproduction can be realized. Further, the interval between the light shielding parts 18 that divide the light emitting part 5 into a plurality of minute regions is determined by photolithography / etching at the apex of the protrusion part 3, and therefore the interval can be made almost the same as the track pitch of the recording medium 14. it can. Therefore, as shown in FIG. 9, when the optical probe 1 is arranged by the suspension 16 with respect to the track row formed on the recording medium 14, the angle θ with the track 15 can be made small.

A method of manufacturing the optical probe 1 in which the light emitting portion 5 is divided into a plurality of minute regions by the light shielding portion 18 will be described with reference to the process chart of FIG. First, as shown in FIG. 10A, a SiO ₂ layer 22 having a thickness of about 1 μm and a single crystal Si layer 23 having a thickness of about 5 to 10 μm are formed on a single crystal Si substrate 21 having a thickness of several 100 μm. So-called SOI substrates 20 that are stacked
To use. As shown in (b), a protrusion-shaped resin 24 is formed on the portion of the single crystal Si layer 23 where the protrusion 3 is to be formed, using photoresist or the like. When forming the protrusion-shaped resin 24, the resin film thickness of the portion where the light-shielding portion 18 that divides the light emitting portion 5 into a plurality of minute regions is formed is made slightly thinner. This can be realized by reducing the exposure amount only in this portion and exposing through a photomask. This protrusion-shaped resin 2
Using the mask 4 as a mask, as shown in (c), the protrusion 3 having the groove 19 in the portion where the light shielding portion 18 is formed is formed in the single crystal Si layer 23. Next, as shown in (d), the single crystal S
A metal film 25 is deposited on the surfaces of the i layer 23 and the protrusions 3. Then, the metal film 25 on the tip portion of the protrusion 3 is removed by FIB or chemical mechanical polishing. By removing the metal film 25 at the tip of the protrusion 3, as shown in (e), the light-shielding portion 18 is left in the groove 19 at the apex of the protrusion 3,
The metal light-shielding film 6 is formed on the surface of the single crystal Si layer 23 and the side surface of the protrusion 3. Next, as shown in (f), the single crystal Si substrate 21 and SiO corresponding to the portion where the protrusion 3 is formed are formed.
The central portion of the _two layers 22 is removed to expose the exposed single crystal Si layer 23.
A photosensitive material (resist) is applied to a position corresponding to the protruding portion 3 of, and light is irradiated through a mask on which a pattern equivalent to the diameter of the microlens 4 is formed, and the photosensitive material is exposed and then developed. . By this development, a pattern resin having a diameter of the microlens remains on the single crystal Si layer 23. Heat and pressure are applied to the remaining pattern resin to form the convex lens-shaped resin 26 as shown in (g). Using the formed convex lens-shaped resin 26 as a mask, the single crystal Si layer 2 is formed.
3 is etched in a vertical direction (anisotropic etching) to produce a microlens 4 as shown in (h).
By forming the light-shielding portion 18 that divides the light emitting portion 5 into a plurality of minute regions by photolithography / etching, the light-shielding portion 18 and its interval can be formed with high precision.

As shown in FIG. 11, the optical probe 1
The glass substrate 30 may be provided on the microlens 4 side. By providing the glass substrate 30 in this way, the rigidity of the optical probe 1 can be further increased, and
Photolithography for producing the microlens 4 can be facilitated. A method for producing the optical probe 1 having the glass substrate 30 will be described with reference to the process chart of FIG.

First, as shown in FIG. 12A, a SiO ₂ layer 22 having a thickness of about 1 μm and a single crystal Si having a thickness of about 5 to 10 μm are formed on a single crystal Si substrate 21 having a thickness of several 100 μm. Layer 2
A so-called SOI substrate 20 in which 3 is stacked is used.
Photosensitive material of the single crystal Si layer 23 of the SOI substrate 20
(Resist) is applied, and as shown in (b), a resist pattern is formed so as to leave a microlens-shaped resist pattern 31 and a portion 32 around which the glass substrate 30 is bonded. When forming this resist pattern, since the photosensitive material is applied to the flat surface of the single crystal Si layer 23, the photosensitive material can be applied uniformly, and the microlens-shaped resist pattern 31 is accurately formed. be able to.

Using this resist pattern as a mask, the single crystal Si layer 23 is etched in a vertical direction (anisotropic etching) to form the microlens 4 and the glass bonding portion 33, as shown in FIG. In this glass joint 33,
As shown in (d), the glass substrate 30 is placed. As the glass substrate 30, for example, # 77 manufactured by Corning Inc.
Use 40. Its thickness is about 0.1 mm to 3 mm. The electrode 34 is pressed onto the upper surface of the glass substrate 30 and the lower surface of the single crystal Si substrate 21, and the electrode 34 is placed in a nitrogen gas or in a vacuum.
While being heated to 350 ° C., a positive voltage of about 300 V is applied to the electrode 34 on the single crystal Si substrate 21 side for about 10 minutes to bond the glass substrate 30 to the glass bonding portion 33 made of single crystal Si. When joining the glass substrates 30, single crystal Si
There is a SiO ₂ layer 22 as an insulating layer between the substrate 21 and the glass bonding portion 33 made of single crystal Si, but the temperature is high,
Since the voltage is also high, a current penetrates or leaks and a current necessary for bonding flows, and the glass substrate 30 can be bonded to the glass bonding portion 33 by anodic bonding. Thereafter, as shown in (e), the electrode 34 is removed, and as shown in (f), the single crystal Si substrate 21 is removed and the SiO ₂ layer 22 is also removed.
Then, as shown in (g), a protrusion-shaped resin 24 is formed by photoresist or the like at the position of the single crystal Si layer 23 forming the protrusion 3 facing the microlens 4. Using the protrusion-shaped resin 24 as a mask, the protrusion 3 is formed as shown in (h). Next, as shown in (i), a metal film 25 is deposited on the surfaces of the single crystal Si layer 23 and the protrusions 3.
Then, the metal film 25 at the tip of the protrusion 3 is removed by FIB, chemical mechanical polishing, or the like, and as shown in (j),
The light shielding portion 18 is left on the apex portion of the protrusion 3, and the metal light shielding film 6 is formed on the surface of the single crystal Si layer 23 and the side surface of the protrusion 3.

When forming the protrusion 3 of the optical probe 1 to which the glass substrate 30 is attached, the single crystal Si layer 2 is formed.
Since the glass substrate 30 is attached to 3, the single crystal Si layer 23 can have a sufficient rigidity and the thickness of the single crystal Si layer 23 can be reduced, and the protrusion 3 to be formed can be brought close to the microlens 4. Therefore, the numerical aperture NA can be improved and the light utilization efficiency can be improved.

In the above description, # 7740 manufactured by Corning Incorporated in the United States was given as an example of the material for the glass substrate 30, but the material is not particularly limited thereto, and # 7740 manufactured by Corning Incorporated in the United States is used.
It is also possible to use 7070 or SW-3 of Iwaki Glass. Moreover, although the case where anodic bonding is used as a method of bonding the single crystal Si layer 23 and the glass substrate 30 has been described, the invention is not limited to this and direct bonding at room temperature may be used. At room temperature bonding, after mirror-polished silicon wafers, glass substrates, and metal substrates are so-called RCA cleaned, two FAB (Fast Atomic Beam) of Ar are simultaneously irradiated to each of the two substrates in the vacuum chamber for about 300 seconds, 10MP
Crimping with the pressure of a. Bonding strength after returning to atmosphere is 12M
Pa or more.

The case where the galvano mirror 13 is provided as the deflector 12 for scanning the laser light incident on the optical probe 1 in the long side direction of the light emitting portion 5 has been described.
As shown in FIG. 2, a polygon mirror 40 is used as the deflector 12, and the laser beam reflected at a right angle by the beam splitter 10 is incident on the optical probe 1 while periodically changing the direction in which the laser beam is reflected by the polygon mirror 40. Alternatively, scanning may be performed in the long side direction of the light emitting portion 5 provided at the apex portion of 3. In this case, the polygon mirror 40 may be moved in the tracking actuation direction shown by an arrow C in FIG. 11 in order to match the center position of the swing width of the emitted light with the center position of the track 15 of the recording medium 14.

As shown in FIG. 14, as the deflector 12, an acousto-optical deflector (hereinafter referred to as an AO deflector) 41 for controlling the deflection direction by an input AC voltage is provided and reflected at a right angle by the beam splitter 10. AO
The light emitting portion 5 provided on the apex portion of the protrusion 3 upon entering the optical probe 1 while periodically changing the deflection direction by the modulator 41
You may make it scan in the long side direction. In this case, in order to wobble the laser light for detecting the tracking error, the AC voltage applied to the AO deflector 41 is set to an AC voltage having a frequency fluctuation corresponding to the required swing width.
By detecting the tracking error by this, by controlling the center frequency of the AC voltage frequency fluctuation from this value,
The AO deflector 41 can be controlled so that the center position of the emitted light deflection width and the track center position of the recording medium 14 coincide with each other. As this AO deflector 41, Ti: LiN
bO ₃ , LiTaO ₃ , ZnO, or the like can be used.

Further, as shown in FIG. 15, an electro-optical deflector (hereinafter referred to as EO deflector) 42 is provided as the deflector 12, and the laser light reflected at a right angle by the beam splitter 10 is deflected by the EO deflector 42. The light may be incident on the optical probe 1 while periodically changing the direction and scanning may be performed in the long side direction of the light emitting portion 5 provided at the apex of the protrusion 3. In this case, the PD 12 is passed from the recording medium 14 through the optical probe 1.
The light incident on is converted into an electric signal by the PD 12, which is input to the feedback circuit 43 to change the amplitude of the AC voltage and output a signal for controlling the EO deflector 42. To wobble the beam for tracking error detection, this AC voltage applied to the EO deflector 42 is made an AC voltage having an amplitude corresponding to the required deflection width. By this, a tracking error is detected, and the bias value of the AC voltage is controlled from this value to control the EO deflector 42 so that the center position of the emitted light deflection width and the track center position of the recording medium 14 coincide with each other. You can This EO
As the deflector 32, Ti: LiNbO ₃ or LiTaO
₃ or the like can be used.

The shape of the electro-optic crystal 44 that constitutes the EO deflector 42 is as shown in the front view of FIG.
It is a cube as shown in the side view of FIG.
It is preferably long in the direction and thin in the z direction perpendicular to the surface on which the electrode 45 is formed. Length (width) of the electrode 45 in the y direction
Are formed so as to change in the x direction. The simplest form of this electrode 45 is a right triangle or a trapezoid as shown in FIG. The refractive index of the electro-optic crystal 44 changes when an electric field is applied. Here, in particular, the Pockels effect in which the refractive index changes in proportion to the electric field is used.
Since the electric field is applied only to the portion where the electrode 45 is formed in the electro-optical crystal 44, the electrode 45 is applied from the voltage source 46.
An electric field generated by applying a voltage to the electrode increases or decreases the refractive index of a portion of the electrode 45 as compared with that of other portions. As a result, according to Snell's equation, the light transmitted through the electro-optical crystal 44 is refracted in the electro-optical crystal 44 and the emitted light is deflected. By irradiating the optical probe 1 with the emitted light, it is possible to scan in the long side direction of the light emitting portion 5 at the tip of the protrusion 4.

Generally, the formula of the index ellipsoid showing the state of the refractive index of the crystal in the Pockels effect can be expressed by the following formulas (1) and (2) using the electro-optic constant tensor and the applied electric field vector.

[0046]

[Equation 1]

As the electro-optic crystal 44, an LN crystal (LiN
When bO ₃ ) is used, the value of each component of the electro-optical constant tensor is as shown in the following formula (3).

[0048]

[Equation 2]

As shown in FIG. 17, consider a case where an electric field Ez is applied in the z-axis direction, which is the optical axis of the electro-optic crystal 44 made of an LN crystal, and light propagates in the x-direction. Here, the optical axis means a direction in which the propagating light propagating through the crystal is always an ordinary ray without depending on the polarization. From the above formulas (1) to (3), the refractive index ellipsoid becomes the following formula (4).

[0050]

[Equation 3]

[0051] represents a case in refractive index _n o, _{n e} is the refractive index _{n z} in the refractive index _{n y} and z polarization of y-polarized light when the electric field Ez = 0. Since the change in the refractive index due to the application of the electric field Ez is small, it can be approximated by the following expression (5).

[0052]

[Equation 4]

By this approximation, the index ellipsoid can be expressed by the following equation (6).

[0054]

[Equation 5]

Therefore, the refractive index changes between y-polarized light and z-polarized light as shown in the following expression (7).

[0056]

[Equation 6]

Here, consider a case where a region having a refractive index distribution is formed as shown in FIG. 18 and light having a beam diameter D is propagated. Focusing on the light passing through the upper end of the beam (referred to as beam A) and the light passing through the lower end of the beam (referred to as beam B) in FIG. 18, the times T _A and T _B required for the beams A and B to pass through the crystal are When the speed is c ₀ , it can be expressed by the following equations (8) and (9).

[0058]

[Equation 7]

Therefore, when the beam A reaches the crystal edge, the beam B jumps out of the crystal by the distance Δx shown in the following equation (10).

[0060]

[Equation 8]

Therefore, since the phases of light are aligned, the light is deflected by the angle θ shown in the following equation (11).

[0062]

[Equation 9]

Further, assuming that this beam is placed in the waste of a Gaussian beam, the diffraction spread half-vertical angle at infinity is given by the following expression (12).

[0064]

[Equation 10]

From this equation (12), the amount by which N spots of one spot radius can be moved when focused
(The number of decomposition points N) can be expressed by the following equation (13).

[0066]

[Equation 11]

From the above, the electro-optic crystal 44 made of the LN crystal can be used as a deflector by providing the electrode 45 of a right triangle or a trapezoid as shown in FIG. Further, the decomposition point N of the light incident on the LN crystal using the equations (7) and (13) can be expressed as the following equation (14).

[0068]

[Equation 12]

[0069] In the case of the LN _{crystal, r 33> r 13, n} o ≒
Since it is n _e, it is parallel to the optical axis where the effect of deflection is large,
That is, polarized light in the z-axis direction (z-polarized light) is made incident. Further, in order to enable tracking signal detection, it is necessary to move the beam from the center of the recorded mark by about the radius thereof. That is, the number of decomposition points required for the deflection element must be 1 or more. Aiming at this, using LN crystal, for example, the thickness is 2 mm, the width w is 10 mm, and the length is 40 m.
For example, as shown in FIG. 19, an electrode 45 having an inclination of 2/40 at the end was formed on the electro-optic crystal 44 of m. In a deflector having such a size, the number N of decomposition points is (15) below for polarized light parallel to the optical axis.
The decomposition score N = 1 can be realized at about V. Where the wavelength is
830nm, and the refractive index _{n o} = 2.2.

[0070]

[Equation 13]

Electro-optic crystal 44 composed of this LN crystal
As shown in FIG. 20, when the electric field is applied parallel to the optical axis and the linearly polarized light E _z parallel to the optical axis direction is incident in the x-axis direction, the amount of movement (deflection amount) of the outgoing beam Figure 2
1 (b), that of the vertical light E _y is shown in FIG. 21 (a). As is clear by comparing the two, it can be seen that the former case has a larger movement amount. That is, the beam can be swung with a lower voltage.

Next, the case where a domain inversion (ferroelectric polarization inversion) type electro-optic crystal is used as the EO deflector 42 will be described with reference to the top view of FIG. 22A and the sectional view of FIG. The EO deflector 42 includes a voltage source 4 for the electrode 45.
When a voltage is applied from No. 6, an electric field is generated in the electro-optic crystal 44. In this EO deflector 42, a plurality of electro-optic crystals 44 are wedge-shaped and are alternately stacked as shown in FIG. 7A, and a portion 44a shown by hatching and a portion 44b other than that are shown.
Have different changes in the refractive index that occur when the same electric field is applied. Each has a wedge shape and is stacked alternately. Here, as shown in FIG. 22, when the light 47 is incident in the x direction perpendicular to the optical axis, refraction occurs due to the refractive index difference at the boundary between the shaded portion 44a and the other portion 44b. Since this phenomenon occurs every time the light 47 passes through the boundary, the light emitted from the EO deflector 42 is deflected. The degree of this deflection can be controlled by the voltage applied to the electrode 45. Therefore, by irradiating the optical probe 1 with the light emitted from the EO deflector 42, the light emitting portion provided at the tip of the protrusion 3 of the optical probe 1 is irradiated. 5 can be scanned.

In the EO deflector 42, the electro-optic crystals 44 having a wedge shape and alternately stacked.
By making the optical axis directions of the shaded portion 44a and the other portion 44b opposite to each other, the voltage applied to the electrode 45 and the power consumption can be further reduced, and the efficiency can be further improved.

Next, the optical probe 1 configured as described above.
The overall configuration of the optical pickup 50 having the optical system 7 and the optical system 7 is shown in the perspective view of FIG. An optical probe 1 for generating near-field light is arranged on the recording medium 14, and the optical probe 1 floats from the surface of the recording medium 14 by several tens nm or comes into contact with the air flow generated by the rotation of the recording medium 14. Slide in the state. Optical probe 1 is suspension 1
It is connected to the arm 51 via 6. The optical system 7, the deflector 12, and the condenser element 52 are mounted on the arm 51, and are moved by the arm motor 53. This arm 51
Moves the optical probe 1 onto a desired track on the recording medium 14, and the optical system 7, the deflector 12, and the condenser element 52 mounted on the recording medium 14 move together with the optical probe 1.
Therefore, since the laser beam emitted from the optical system 7 is automatically irradiated to the optical probe 1, the optical system 7 and the optical probe 1
It is not necessary to provide an actuator or a control system for aligning the. Further, the deflector 12 has an elongated AO shape.
Since the deflector 41 and the EO deflector 42 can be laid down on the arm 51 and mounted, the arm 51 can be made thin and compact.

The arrangement of the optical probe 1, arm 51, optical system 7, deflector 12 and condenser element 52 of the optical pickup 50 is shown in FIG. The deflector 12 shown in FIG. 24A is composed of, for example, an EO deflector 42, and the condensing element 52 is composed of a right-angled prism 54 integrally formed with the EO deflector 42 by using the same material as that of the EO deflector 42. It has a reflective film 55 on it and is arranged directly above the optical probe 1. Focusing element 5
2 and a portion of the arm 51 corresponding to the optical path of the optical probe 1 is provided with a hole or a transparent material such as glass is fitted therein. The light deflected by the deflector 12 is reflected by the reflection film 55 of the condenser element 52, enters the optical probe 1, and is condensed by the microlens 4. Thereby, optical scanning for tracking or high speed recording / reproducing can be performed. In addition, the microlens 4 is attached to the optical probe 1.
Since the optical probe 1 can be irradiated with the parallel light as it is, the alignment of the light irradiated from the condensing element 52 and the optical probe 1 is determined by the positional relationship between the microlens 4 and the protrusion 3. If the determination is made with high accuracy when the probe 1 is manufactured, the positional relationship between the two does not change during use, so that the accuracy required for the alignment between the light emitted from the condensing element 52 and the optical probe 1 is relaxed. be able to.

The condensing element 52 is shown in FIG.
As shown in FIG. 5, the reflecting film 55 is provided on the inclined surface of the right-angled prism 56 provided independently of the deflector 12, and the right-angled prism 56 is provided.
May be connected to the deflector 12 with a translucent adhesive. Further, as shown in FIG. 24C, for example, the EO deflector 42
Is formed integrally with the deflector 12 using the same material as that of the reflective lens 57, or the reflective film 57 is formed on the spherical surface of the reflective lens 57 formed of the same material as that of the EO deflector 42 and the like independently of the deflector 12.
5 may be provided to serve as the condensing element 52. By using the reflective lens 57 as the condensing element 52 in this way, it is possible to combine the two lenses of the reflective lens 57 and the microlens 4 of the optical probe 1 with a numerical aperture N.
A can be further improved to reduce the diameter of the focused spot, and the light utilization efficiency can be increased. It is preferable that the right angle prisms 54 and 56 forming the condenser element 52 and the reflective film 55 provided on the reflective lens 57 are not electrically connected to the EO deflector 42 and the like and the electrodes. Further, as shown in FIG. 25, the condenser lens 5 is provided between the condenser element 52 and the optical probe 1.
By providing 8, the focused spot diameter can be made smaller.

In the above description, the case where the convex lens is used as the microlens 4 of the optical probe 1 has been described. However, as shown in the sectional views of FIGS. 26A and 26B, the high refractive index material 61 having the refractive index n1 is used. And a high refractive index material 62 having a refractive index n2 larger than the refractive index n1 is used to form a lens portion with the high refractive index material 62 having a refractive index n2, or as shown in FIG. The formed convex lenses 64 may be provided so as to face each other.

Further, the thickness of the metal light-shielding film 6 provided on the surface of the substrate 2 of the optical probe 1 may be formed so as to be the same as the height of the protrusion 3 as shown in FIG. By thus forming the tip of the protrusion 3 and the surface of the metal light-shielding film 6 on the same surface, when the protrusion 3 is used so as to face the recording medium 14, stress concentrates on the apex portion of the protrusion 3. This can be prevented and the projection 3 can be used stably without being damaged.

In the above description, the optical probe 1 is made of a single crystal.
Although the case where it is made of Si has been explained,
The probe 1 may be manufactured. Single crystal Si, SiO₂, Ge, moth
Lath, crystalline quartz, C (diamond), amorphous Si,
Microcrystal Si, Polycrystalline Si, Si_xN
_y(x and y are arbitrary), TiO₂, ZnO, TeO₂, Al₂O₃, Y₂O₃, La₂
O₂S, LiGaO₂, BaTiO₃, SrTiO₃, PbTiO₃, KNbO ₃, K
(Ta, Nb) O₃(KTN), LiNbO₃, LiTaO₃, Pb (Mg_1/3Nb_2/3) O₃,
(Pb, La) (Zr, Ti) O₂, (Pb, La) (Hf, Ti) O₃, PbGeO₃, Li₂GeO
₃, MgAl₂O_Four, CoFe₂O_Four, (Sr, Ba) Nb₂O₆, La₂Ti ₂O₇, Nd₂Ti
₂O₇, Ba₂TiSi₁₂O₈, Pb_FiveGe₃O₁₁, Bi_FourGe₃O₁₂, Bi_FourSi
₃O₁₂, Y₃Al_FiveO₁₂, Gd₃Fe_FiveO₁₂, (Gd, Bi)₃Fe_FiveO₁₂, Ba₂NaNb
O₁₅, Bi₁₂GeO₂O, Bi₁₂SiO₂, Ca₁₂Al₁₄O₃₃, LiF, NaF, K
F, RbF, CsF, NaCl, KCl, RbCl, CsCl, AgCl, TlCl, Cu
Cl, LiBr, NaBr, KBr, CsBr, AgBr, TlBr, LiI, NaI, K
I, CsI, Tl (Br, I), Tl (Cl, Br), MgF₂, CaF₂, SrF₂, Ba
F₂, PbF₂, Hg₂CI₂, FeF₃, CsPbCl₃, BaMgF_Four, BaZnF_Four, N
a₂SbF_Five, LiClO_Four・ 3H₂O, CdHg (SCN)_Four, ZnS, ZnSe, ZnTe,
CdS, CdSe, CdTe, a-HgS, PbS, PbSe, EuS, EuSe, GaS
e, LiInS₂, AgGaS₂, AgGaSe₂, TiInS₂, TiInSe₂, TlGaS
e₂, TlGaS₂, As₂S₃, As₂Se₃, Ag₃AsS₃, Ag₃SbS₃, CdGa₂
S_Four, CdCr₂S_Four, TlTa₃S _Four, Tl₃TaSe_Four, Tl₃VS_Four, Tl₃AsS_Four, T
l₃PSe_Four, GaP, GaAs, GaN, (Ga, Al) As, Ga (As, P), (lnG
a) P, (lnGa) As, (Ga, AI) Sb, Ga (AsSb), (lnGa) (AsP),
(GaAI) (AsSb), ZnGeP₂, CaCO₃, NaNO₃, A-HIO₃, A-LiIO
₃, KIO₂F₂, FeBO₃, Fe₃BO₆, KB_FiveO₈・ 4H₂O, BeSO_Four・ 2H₂O,
CuSO_Four・ 5H₂O, Li₂SO_Four・ H₂O, KH₂PO_Four, KD₂PO_Four, NH_FourH₂PO_Four,
KH₂AsO_Four, KD₂AsO_Four CSH₂AsO_Four, CsD₂AsO_Four, KTiOPO_Four, RbTiO
PO_Four, (K, Rb) TiOPO_Four, PbMoO_Four, A-Gd₂(MoO_Four)₃, A-Tb₂(MoO
_Four)₃, Pb₂MoO_Five, Bi₂WO₆, K₂MoOS₃・ KCl, YVO_FourCa₃(VO_Four)₂,
Pb_Five(GeO_Four) (VO_Four)₂, CO (NH₂)₂, Li (COOH) ・ H₂O, Sr (COO
H)₂, (NH_FourCH₂(COOH)₃H₂SO_Four, (ND_FourCD₂(COOD)₃D₂SO_Four, (NH_FourCH
₂(COOH)₃H₂BeF, (NH_Four)₂C₂O_Four・ H₂O, C_FourH₃N₃O_Four, C_FourH₉NO₃, C
₆H_Four(NO₂), C₆H_FourNO₂Br, C₆H_FourNO₂CI, C₆H_FourNO₂NH₂, C₆H_Four
(NH_Four) OH, C₆H_Four(CO₂)₂HCs, C₆H_Four(CO₂)₂HRb, C₆H₃NO₂CH₃N
H₂, C₆H₃CH₃(NH₂)₂, C₆H₁₂O_Five・ H₂OKH (C₈H_FourO_Four), C1OH11N
₃O₆, [CH₂・ CF₂] n.

[0080]

As described above, the present invention is formed of the same material as the substrate formed of a high refractive index material, has a tapered surface on the outer wall, and has an elongated light emitting portion at the tip. By providing a condenser lens made of the same material as the substrate on the surface facing the protruding portion, the light incident on the condenser lens is prevented from being reflected at the boundary between the condenser lens and the substrate, and is incident. The light can be effectively used, and the light utilization efficiency can be improved. Further, since the incident light is condensed by the condenser lens on the light emitting portion, a very small light spot can be realized on the light emitting portion, the recording density can be improved, and highly accurate tracking control can be realized.

In addition, a plurality of light-shielding portions may be provided in the light emitting portion provided at the tip of the protrusion at substantially equal intervals in the long side direction of the elongated shape, and the light emitting portion may be divided into slits. As a result, a smaller light spot can be realized at the light emitting portion, and a high input / output bit rate can be realized.

Further, by providing a reinforcing member on the outer peripheral portion of the condenser lens, the rigidity of the optical probe can be increased, and the condenser lens can be arranged closer to the protrusion, thereby improving the numerical aperture and utilizing the light. It is possible to improve efficiency and recording density.

Further, by providing a transparent substrate on the side of the condenser lens, the rigidity of the optical probe is further enhanced, and
The condenser lens can be easily manufactured.

When the refractive index of the condenser lens, the substrate and the protrusion is n and the wavelength of the light incident on the condenser lens is λ, the long side of the elongated light emitting portion provided at the tip of the protrusion. Of the length a and the length b of the short side are a ≧ (λ / 2n), b <(λ
By defining the shape of the light emitting portion so as to satisfy the condition of / 2n), it is possible to stably realize a small light spot on the light emitting portion.

Further, in the optical pickup having the optical probe, the elongated light emitting portion of the optical probe is deflected between the optical system for emitting the recording / reproducing light and the optical probe to deflect the light emitted from the optical system. By providing the light deflecting means for scanning in the long side direction, it is possible to stably scan the light in the long side direction of the elongated light emitting part of the optical probe, and to realize a high input / output bit rate. You can

By using a galvanometer mirror, a rotating polygon mirror, an acousto-optic deflector or an electro-optic deflector as the light deflecting means, the elongated shape of the light emitting portion of the optical probe can be stabilized in the long side direction with a simple structure. Light can be scanned.

Further, the electro-optical deflector is composed of a cubic electro-optical crystal, and an electrode parallel to the light transmitting direction is formed, and the width of the electrode is formed in a shape changing along the light transmitting direction. Thus, the light scanning in the long side direction of the elongated light emitting portion of the optical probe can be stably deflected.

Further, as an electro-optic crystal, LN (LiN
By using a bO ₃ ) crystal and determining the shape of the electrode so that an electric field is applied in parallel with the optical axis of the LN crystal, it is possible to deflect the light incident on the optical probe with a simple configuration.

Further, by using a domain inversion type electro-optical crystal as the electro-optical crystal, the degree of deflection can be controlled by the applied voltage, and the light incident on the optical probe can be stably deflected.

Further, by making the light incident on the electro-optic crystal linearly polarized in the direction parallel to the optical axis, the light can be deflected at a lower voltage, and the power consumption during recording / reproduction can be reduced. it can.

Further, the optical probe is provided below the tip of the arm, and the optical system and the light deflecting means are mounted on the upper part of the arm so that the light converging means for changing the optical path of the light from the light deflecting means is incident on the optical probe. As a result, the actuator and the control system for aligning the deflecting means and the optical probe are unnecessary, and the size and simplification of the device can be achieved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an optical probe of the present invention.

FIG. 2 is a perspective view showing a configuration of an optical probe.

FIG. 3 is a configuration diagram of an optical pickup.

FIG. 4 is a layout view of an optical probe with respect to a track of a recording medium.

FIG. 5 is a configuration diagram of a second optical probe.

FIG. 6 is a process drawing showing the method of manufacturing the second optical probe.

FIG. 7 is a configuration diagram of a photomask for producing a microlens of an optical probe.

FIG. 8 is a configuration diagram of a third optical probe.

FIG. 9 is a layout view of a third optical probe with respect to a track of a recording medium.

FIG. 10 is a process drawing showing the manufacturing method of the third optical probe.

FIG. 11 is a configuration diagram of a fourth optical probe.

FIG. 12 is a process drawing showing the manufacturing method of the fourth optical probe.

FIG. 13 is a configuration diagram of a second optical pickup.

FIG. 14 is a configuration diagram of a third optical pickup.

FIG. 15 is a configuration diagram of a fourth optical pickup.

FIG. 16 is a configuration diagram of an EO deflector.

FIG. 17 is a schematic diagram showing the direction of voltage application to the electro-optic crystal of the EO deflector.

FIG. 18 is a schematic diagram showing a beam that passes through an electro-optic crystal.

FIG. 19 is a layout view showing electrode shapes for an electro-optic crystal of an EO deflector.

FIG. 20 is a schematic diagram showing the incident direction of light to the EO deflector.

FIG. 21 is a change characteristic diagram of the amount of movement of the outgoing beam with respect to the electric field applied to the EO deflector.

FIG. 22. E using a domain inversion type electro-optic crystal
It is a block diagram of an O deflector.

FIG. 23 is an overall configuration diagram of an optical pickup.

FIG. 24 is a layout diagram of an optical system, a deflector, a condensing element, and an optical probe for an arm of an optical pickup.

FIG. 25 is another layout diagram of the optical system, the deflector, the condensing element, and the optical probe for the arm of the optical pickup.

FIG. 26 is a cross-sectional view showing another configuration of the microlens.

FIG. 27 is a configuration diagram of a fifth optical pickup.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Optical probe, 2; Substrate, 3; Projection part, 4; Microlens, 5; Light emitting part, 6; Metal light shielding film, 7; Optical system,
8; LD, 9; Collimator lens, 10; Beam splitter, 11; PD, 12; Deflector, 13; Galvano mirror, 14; Recording medium, 15; Track, 16; Suspension, 17; Reinforcing section, 18; Light-shielding section , 40; polygon mirror, 41; AO deflector, 42; EO deflector.

Continued front page    (72) Inventor Hironori Mifune             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Motoichi Otsu             3-2-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture             No. Within Kanagawa Academy of Science and Technology (72) Inventor Motonobu Korogi             3-2-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture             No. Within Kanagawa Academy of Science and Technology (72) Inventor Takashi Yai             3184-21 Nogawa, Miyamae-ku, Kawasaki-shi, Kanagawa F term (reference) 5D118 AA13 CA13 DC07 DC13 DC16                 5D119 AA11 AA22 AA43 EC32 EC39                       JA34 JA43 JA52 JA54 JA55                       MA05                 5D789 AA11 AA22 AA43 CA21 CA22                       CA23 EC32 EC39 JA34 JA43                       JA52 JA54 JA55 MA05

Claims (15)

[Claims] 1. A substrate formed of a high refractive index material, a protrusion formed of the same material as the substrate, having a tapered surface on its outer wall and an elongated light emitting portion at its tip, and a substrate. An optical probe having a condensing lens formed of the same material as the substrate on a surface facing the protruding portion. 2. A plurality of light-shielding portions are provided in the light emitting portion provided at the tip of the protrusion at substantially equal intervals in the long side direction of the elongated shape, and the light emitting portion is divided into slits. The optical probe according to claim 1. 3. The optical probe according to claim 1, wherein a reinforcing member is provided on an outer peripheral portion of the condenser lens. 4. The optical probe according to claim 1, wherein a transparent substrate is provided on the condenser lens side. 5. When the refractive index of the condenser lens, the substrate and the protrusion is n and the wavelength of light incident on the condenser lens is λ, the length of the elongated light emitting portion provided at the tip of the protrusion is long. The shape of the light emitting portion is determined so that the side length a and the short side length b satisfy the condition of a ≧ (λ / 2n) b <(λ / 2n).
5. The optical probe according to any one of 4 to 4. 6. An optical pickup including the optical probe according to claim 1, wherein the optical probe emits light for recording and reproduction, and the optical probe.
An optical pickup comprising: a light deflecting unit that deflects light emitted from an optical system and scans the light emitting portion of the optical probe in the long side direction. 7. The optical pickup according to claim 6, wherein a galvano mirror is used as the light deflecting means. 8. The optical pickup according to claim 6, wherein a rotating polygon mirror is used as the light deflecting means. 9. The optical pickup according to claim 6, wherein an acousto-optic deflector is used as the light deflecting means. 10. The optical element for an optical pickup according to claim 6, wherein an electro-optical deflector is used as the light deflecting means. 11. The electro-optical deflector is composed of a cubic electro-optical crystal, electrodes are formed parallel to the light transmitting direction, and the width of the electrodes is formed in a shape changing along the light transmitting direction. The optical pickup according to claim 10, which is provided. 12. LN (LiN as the electro-optic crystal
The optical pickup according to claim 11, wherein a shape of the electrode is determined so that an electric field is applied in parallel with an optical axis of the LN crystal by using a bO ₃ ) crystal. 13. The optical pickup according to claim 11, wherein a domain inversion type electro-optic crystal is used as the electro-optic crystal. 14. The optical pickup according to claim 11, 12 or 13, wherein the light incident on the electro-optic crystal is linearly polarized light in a direction parallel to the optical axis. 15. The optical probe is provided below the tip of the arm, and the optical system, the optical deflector, and the condenser for changing the optical path of the light from the optical deflector to enter the optical probe are mounted on the upper part of the arm. Item 15. The optical pickup according to any one of items 11 to 14.