JP2005513845A - Optical disk head having bowtie grating antenna and slider for optical focusing, and method of manufacturing the same - Google Patents

Abstract

  A slider device (1300) has been developed to help provide a gap between the read / write head (1320) and the storage medium (1310) to improve the size and polarization characteristics of the illumination spot. A grating antenna amplifier (1110) has been developed. The grating antenna (1110) is attached to the gray scale slider (1130) to obtain the distance between the illumination spot (1150) and the antenna (1110) in the near field region.

Description

  The present invention relates to the positioning of optical antennas, optical lenses, and electromagnetic readers and writers, and more particularly, a desired distance that includes a partially varying surface and has a maximum intensity peak. The invention relates to the use of a micro-laminated optical lens connected to an amplification grating antenna as an optical antenna and a molding surface so as to create a concentrated optical spot of desired polarization.

  Storage of information on magnetic media is limited by the size of the light intensity spot collected at the desired storage location. The logic / analog bit can be stored as its strength unwinds the polarization of the medium. The smaller the spot size, the smaller the storage space required for one bit and the more information can be stored on the medium.

  To obtain a focused spot, current devices illuminate an antenna that re-radiates the light, and a moderately concentrated part used for storage / reading logic / analog bits in the medium Various patterns including are formed. A spot size smaller than the irradiation wavelength (λ) is realized by an antenna composed of a plurality of conductive members arranged in a path of incident light, separated by a gap whose lateral dimension is smaller than the λ.

  An example of a conventional device is the antenna device of Grover et al. (US Pat. No. 5,696,372). FIGS. 1 and 2 show a Glover antenna with two antenna arms 16, 18 with a gap 24 of lateral dimension “d” separating the ends 20, 22 of the conductive arms 16, 18. The incident light forms an initial spot size 26 on the target medium 30. When the antenna arms 16 and 18 are disposed in the irradiation path, incident light on the antenna arms 16 and 18 causes an induced current in the conductors (16 and 18). The induced current causes charge accumulation at the ends 20, 22 and the resulting displacement current is caused between the ends. The displacement current causes re-radiation similar to that caused by a dipole of dimension “d” that forms a spot size of the same dimension on the target medium 30.

  In order to read the information, the gap 24 is placed close to the target medium 30 to be queried. A field close to the gap 24 caused by illumination of the target medium 30 (eg, off-axis illumination, irradiation from near the target medium 30, self induced emanations, etc.) ) 43 generates a induced current in the conductive arms 16, 18 that produces reradiated illumination as described above. The re-emitted light can be directed upwards (away from the target medium 30) through the optics to be read.

  The disadvantage of multiple solid antennas is the overlap where the re-radiation field is lower than the desired maximum peak in the illuminated field and larger than the desired spot size at the desired distance from the antenna. It is a depolarized state during the superposition process.

  Therefore, a system / device / method that can create a smaller spot size while maintaining polarization can allow for the storage and reading of larger amounts of data.

  Read and write functions occur in near field areas. In addition to reducing the irradiation spot size, the placement of the antenna relative to the target medium is important. Several mechanisms have been developed to move the reading and writing device over the target media. FIG. 6 shows a conventional apparatus 600 for directing a focused optical beam 660 onto a focused spot (reference numeral 760 in FIG. 7). This device is a silicon layer 610 having a plurality of metal layers 620, 630 disposed thereon. Below one of these layers is a waveguide 640 that includes either a hole or a refractive index 650 of different index. This device is used rotated to one side of it to direct / guide the optical beam 660 to the desired spot on the recording medium.

  FIG. 7 shows a state in which the apparatus described in FIG. 6 is used for a read / write apparatus 700 used for a rotary magnetic or optical storage / reading apparatus. The optical beam radiation 710 is collected at the entrance of the waveguide structure 740 by a condenser lens 720 that makes the initial radiation 710 a condensed radiation 730. The internally reflected beam emerges as an irradiation 750 guided through the waveguide and irradiates the target medium 770 with an irradiation spot 760. A general disadvantage of a device similar to that described is the size of the component. That is, since the component parts must be accurately attached to each other and the spot size is 200 nm or more, these are factors that limit the storage space of the recording medium. Also, having to combine the various components substantially increases the cost.

  A delivery system that can maintain an optimum spacing between the read / write device and the target medium increases storage speed by providing a stable state, thereby storing logic / analog polarization values. Helps determine the total amount of time needed.

  Thus, an integrated transmission device that provides optimum spacing between the target medium and the read / write head, alone or in the context of a system / device / method that can produce smaller spot sizes while maintaining polarization. Thus, it is possible to store and read a larger amount of data in a cheaper and more reliable manner than conventional devices.

  Accordingly, it is an object of the present invention to provide a read / write device that can maintain a desired position of the read / write head relative to a target medium using a molded surface that is integral with the read / write device.

  It is also an object of the present invention to provide a grating antenna or set of grating antennas in which the superimposed re-radiating field produces the desired spot size, intensity and polarization at the desired location, thereby solving the above-mentioned problems. is there. Here, the lattice antenna is composed of a plurality of lattices or a set of lattices.

  It is a further object of the present invention to provide a gray scale slider transmission device that assists in the proper separation between the read / write device and the target medium, the transmission device integrating a plurality of components. , Reduce manufacturing costs and improve reliability.

  The slider manufacturing method of the present invention includes a step of developing a grayscale mask having a pattern of a predetermined molding surface, and the predetermined molding surface is sufficient for a writing / reading device to obtain a predetermined distance on a storage medium. A step of placing a photoresist on the substrate, and exposing the photoresist through the grayscale mask with irradiation light until the photoresist is developed. Removing the undeveloped photoresist to produce an indication of the predetermined molding surface pattern with the developed photoresist, and forming a molding surface corresponding to the predetermined molding surface pattern on the substrate. Etching the developed photoresist and the substrate.

  The slider manufacturing method of the present invention includes a step of preparing a mold having an uneven shape opposite to a predetermined molding surface pattern, a step of preparing a curable material, and a step of arranging the curable material in the mold. And curing the curable material with the mold to create a molded surface having a shape corresponding to the predetermined molded surface pattern on the curable material, the predetermined molded surface on a storage medium. It is chosen to produce a slider that raises the writing / reading device sufficiently to obtain a predetermined distance.

  Furthermore, the slider manufacturing method of the present invention includes a step of preparing a mold having a concavo-convex shape opposite to a predetermined molding surface pattern, a step of preparing a molding material, a step of arranging the molding material in the mold, Embossing the molding material with the mold to create a molding surface having a shape corresponding to the predetermined molding surface pattern on the molding material, the predetermined molding surface having a predetermined distance on the storage medium. It is chosen to produce a slider that sufficiently raises the writing / reading device to obtain.

  The irradiation spot forming apparatus of the present invention includes a first grating and a second grating, and the first and second gratings are irradiated with incident light having a specific wavelength, and the first and second gratings are irradiated. The grating is composed of a plurality of grating elements, and the first and second gratings are separated by a distance smaller than the characteristic wavelength, and the grating antenna has a desired size and polarization spot size on the target medium. The light that forms is re-radiated.

  The irradiation spot forming method of the present invention includes a step of positioning a first grating and a second grating that are separated from each other by a predetermined distance and are composed of a plurality of grating elements, and incident light having a characteristic wavelength larger than the predetermined distance. Irradiating the first and second gratings, wherein the irradiation re-radiates the first and second gratings to form spots of the desired size and polarization on the target medium. .

  The reading and writing optical apparatus according to the present invention includes an amplification antenna including a first grating and a second grating, and the first and second gratings are irradiated with incident light having a specific wavelength. The first and second gratings are composed of a plurality of grating elements, the first and second gratings are separated by a distance smaller than the characteristic wavelength, and the grating antenna has a desired size on the target medium. And re-radiating the light forming the polarization spot size, further comprising a movable transmission device, the transmission device comprising a lens structure, the lens structure being an integrated part for collecting incident light The condensed incident light becomes incident light that irradiates the first and second gratings, and the orientations of the first and second gratings are maintained with respect to the lens structure. , Look-up and further comprising a write circuit, said write circuit sets the polarization of the target medium in the spot, the read circuit is intended for reading the polarization of the target medium in a given area.

  The scope of the invention will become apparent from the detailed description provided herein. However, the detailed description and specific examples, while indicating the preferred embodiment of the invention, are given by way of illustration only. Accordingly, various modifications and improvements within the spirit and scope of the present invention will become apparent to those skilled in the art from the detailed description.

  The present invention will be more fully understood from the following detailed description and the accompanying drawings, which are merely exemplary and do not limit the present invention.

  The present invention is a method / apparatus that provides a transmission device that assists in spacing between the read / write device and the target storage medium and / or reduces the illumination spot size while maintaining an effective polarization level. The use of grating antennas to make.

  A grating antenna is similar to a diffraction grating that produces a superposition of transmitted fields. The superposition produces maximum and minimum peaks in the illumination field as a function of position from the grating. The peak has a more concentrated spatial position than the diffraction grating or the two solid antennas described in the background art. Therefore, providing the antenna with a grating structure will result in a concentrated peak of intensity that is smaller than that obtained with current devices of solid re-radiating displacement.

  A grating antenna 300, which is a preferred embodiment of the present invention, is shown in FIG. In the present embodiment, the bow tie grating antenna 300 is composed of a pair of two triangular gratings 370 and 380, and each set is composed of a set of grating elements 390. Note that the lattices 370 and 380 are not limited to two, and are not limited to triangles. The gratings 370 and 380 are separated by a gap distance “D” for the same purpose as “d” in FIG. 1 described above. The length “L” 340 of the arrayed gratings 370 and 380 is variable from millimeter order to nanometer order. Similarly, the grating width “W” 360 is also variable from millimeter order to nanometer order. The dimensions “W”, “L”, and “D” will vary depending on the manufacturing method, but in any case the dimension “D” must be smaller than the irradiation wavelength. In the illustrated embodiment, each grating element may be individually modified or operated in combination for a particular set of grating antennas. Although FIG. 3 shows a triangular grid, as described above, the present invention is not intended to be limited to a triangular grid. The grating may be a spiral or circle of a predetermined shape necessary to obtain the desired illumination spot pattern.

  The grating can be formed using microfabrication methods similar to semiconductor etching, and with similar materials (eg, silicon, silicon nitride, conductive metals, semiconductors, and other similar materials) with the desired optical properties. It can be formed. Similarly, the grating may be formed by a method using adding techniques instead of an etching technique or a curing process to form a pattern, or an unnecessary part in the case of curing. It may be formed by using a removing method for removing. The grating may be transparent to one polarization of incident light or may be conductive to different polarizations of the same incident light. The description here does not limit the material composition of the lattice. The grating may be made of any material that meets the conduction requirements that produce re-emitted light.

  The initial illumination is coherent, semi-interferent, depending on whether the spot size polarization is important for a particular use of the invention and whether a portion of the illumination includes wavelengths greater than the grating spacing. Or incoherent illumination devices (eg, lasers, VIXELS, focused lamp systems, and other similar coherent, semi-coherent or incoherent illumination sources) . The irradiation source may be integrated with the transmission device on a single substrate.

  FIG. 4 shows a comparison of spot patterns in the near field region generated by the solid bow tie antenna and the lattice antenna according to the present invention. Stronger areas appear white. As can be seen in the figure, the grating bowtie has three bright spot illuminations consisting of one central spot and two lobe spots. On the other hand, the corresponding spot pattern of the solid bow tie has one bright spot with two similar dark lobe spots with the same intensity as the central spot and lobe spot of the grating bow tie antenna. The center spot of the solid bowtie antenna represents the normal size of illumination currently available. As can be seen, the lobe spot of the grid bow tie antenna has a smaller but similar intensity relative to the central spot of the solid bow tie antenna. Thus, the lattice bowtie lobe spot can be used to illuminate the target medium to facilitate storing or reading information by being smaller in size than the spot of a conventional solid bowtie antenna.

  FIG. 5 shows an antenna and a radiating spoke wheel microfabricated in the micrometer to nanometer range by the inventor's in-house method. The same method and equipment can be used to make a grating antenna according to the present invention.

  Once the antenna is created, the transmission device must be attached at or near the antenna in order to direct the illuminating light into the antenna to the desired location on the target medium. A transmission apparatus 800 according to an embodiment of the present invention is shown in FIG. In this embodiment, lens structure 820 receives optical light illumination 810. Then, the light 840 passes through the microlens focusing unit 830 and is focused by the lens 830 onto the amplification grating antenna 850 similar to that shown in FIG. Here, the amplification antenna 850 is laminated on the lens structure 820 or embedded in the lens structure 820, or is laminated on the lens structure 820 in a state of being separated from the lens structure 820 by a gap. A grayscale slider 870 is attached to the bottom of the lens structure 820. The grayscale slider 870 includes another layer having a lens or other focusing structure to help focus the light on the amplifying antenna. The amplification grating antenna 850 will generate a spot on the target medium (reference numeral 970 in FIG. 9). In embodiments of the magnetic target medium, the polarization of the medium is performed by driving the read / write circuit 860 as one skilled in the art can imagine.

  The gray scale slider is a micromachined molding surface 880. The surface 880 raises the transmission device 800 when the transmission device is moved relative to the target medium (reference numeral 970 in FIG. 9). The molding surface 880 can be microfabricated or grayscale plasma etched, in this case referred to as a grayscale slider. The molding surface can be either a master mold, a pressing method in which the slider material is punched, or a curing method in which the mold holds a curable substance that becomes a mold shape upon curing. It can be molded using a heel. Here we have referred to grayscale sliders several times, but the extent of the slider is any molded surface that is attached to or integrated with the transmission device used to raise as it moves relative to the target medium. Is also included. Accordingly, the discussion herein should not be construed as limiting the slider to a grayscale slider formed by a grayscale method. The molding surface 880 may be any combination of shapes that are gently curved, stepped, or that provide the desired elevation characteristics.

  The amplification grating antenna 850 can have various shapes and sizes, and discussion herein should not be construed as limiting the antenna to a triangular shape. It is contemplated that various shapes of gratings forming the antenna are within the scope of the present invention.

  In addition, the amplification grating antenna 850, the lens 830, the lens structure 820, and the slider 870 may be integrally formed on a substrate etched by plasma etching, molding, curing, stamping, vapor deposition, or a combination of these methods. The surface of the lens structure 820 in parallel with the target medium may be patterned to form a slider 870 that allows the surface to float across the surface of the target medium (eg, recording material) without contact. . FIG. 9 shows an integrated device etched from a single substrate. FIG. 9 shows the unity of antenna 850, lens 830, lens structure 820 and slider surface 880 etched from a single substrate, each element being provided in separate etched layers. The optical cover layer 1000 may be additionally integrated (for example, bonded) as shown in FIG. The cover layer may be any material that can transmit a portion of incident light.

  Although not shown in FIG. 10, includes additional layers that include light sources (eg, VIXELS, laser diodes, and other similar illumination sources that can be included in the semiconductor layer) for use with the read / write device May be.

  FIG. 11 illustrates the use of apparatus 1100 within the scope of the present invention. The transmission apparatus as described above with reference to FIG. 8 condenses incident light on the grating antenna 1110. The grating antenna re-radiates the initial radiation that forms re-radiated light 1140. The re-radiated light forms an irradiation spot 1150 having a predetermined intensity and spot polarization on the target medium 1170. Read / write circuit 1120 is used to set or read the polarization of the target medium by illumination spot 1150. The transmission device shown in FIG. 11 includes a gray scale slider 1130 that raises the transmission device so that it can perform a relative motion 1180 with respect to a target medium that can rotate in the direction of arrow 1190. The gray scale slider can be formed to provide an optimal spacing between the target medium 1170 and the read / write device 1100.

  In another embodiment of the present invention, the slider may be integrated with a conventional read / write device, where the inventive concept includes a slider to raise the conventional read / write device. It is. FIG. 12 shows a grayscale slider 1210 integrated with the conventional read / write apparatus shown in FIG.

  FIGS. 13A and 13B show various combinations of the orientation of the slider surface 880 opposite the target material 770. The slider 1330 may be separated on the surface 1310 from the read and / or write head 1320 as shown in FIG. 13A, even if a slider is used with a conventional read / write device or grating antenna device, or As shown in FIG. 13B, a read and / or write head 1370 may be integrated or laminated on the slider 1360.

  Various variations in the design of the grating antenna and / or slider combination to raise the read / write device may be realized by the present invention. It will be obvious to those skilled in the art to modify the present invention as described above. Such variations are not to be construed as departing from the spirit and scope of the invention, and all variations that are obvious to one skilled in the art are intended to be included within the scope of the appended claims.

FIG. 1 shows a conventional solid bowtie antenna device. FIG. 2 shows a conventional solid bowtie antenna device. FIG. 3 shows a preferred embodiment of a grating antenna according to the present invention. FIG. 4 shows a simulated near field position comparison between a solid antenna and a grating antenna of one embodiment of the present invention for the development of a low intensity re-radiation spot. Indicates. FIG. 5 is a microscopic image of several different sized solid bowtie antennas manufactured with a wheel structure made to demonstrate our ability of the present invention. FIG. 6 shows a prior art transmission waveguide structure. FIG. 7 shows the use of the structure of FIG. 6 to focus the optical beam. FIG. 8 shows a preferred embodiment of a grayscale slider transmission apparatus according to the present invention. FIG. 9 shows various integrated slider transmission devices. FIG. 10 shows various integrated slider transmission devices. FIG. 11 shows the embodiment of FIG. 8 attached to a gray scale slider that was used to maintain various near field positions from the target media forming the read / write device. FIG. 12 shows another embodiment of the present invention having a gray scale slider integrated with a conventional read / write device. FIG. 13A shows different combinations of gray scale slider positioning relative to the read / write head on the surface opposite the target medium. FIG. 13B shows different combinations of gray scale slider positioning relative to the read / write head on the surface opposite the target medium.

Explanation of symbols

300 ... Bowtie grating antenna 320 ... Gap between gratings 340 ... Grating length 360 ... Grating widths 370 and 380 ... Grating 390 ... Grating element 800 ... Transmission device 820 ... Lens structure 830 ... Lens 840 ... Light 850 ... Amplifying grating antenna 860 ... Read / write circuit 870 ... Gray scale slider 880 ... Molding surface

Claims (29)

  The first and second gratings are irradiated with incident light having a specific wavelength, and the first and second gratings are composed of a plurality of grating elements. The first and second gratings are separated by a distance smaller than the characteristic wavelength, and the antenna comprising the first and second gratings has a desired size and a polarization spot size on the target medium. An irradiation spot forming apparatus characterized by re-emitting radiation to be formed.   2. The spot size according to claim 1, wherein the spot size is smaller than a spot size formed by an irradiation spot forming apparatus having a similar size and shape including a solid portion in place of the first and second gratings. Irradiation spot forming device.   The transmission device further includes a movable transmission device, and the transmission device includes a lens structure, and the lens structure includes an integrated portion that collects incident light, and the collected incident light is the first and second 2. The irradiation spot forming apparatus according to claim 1, wherein the first and second grating orientations are maintained with respect to the lens structure.   A slider, wherein the slider is attached to the transmission device on the same side facing the first and second gratings, and the slider is moved when the transmission device is moved relative to the target medium; The irradiation spot forming apparatus according to claim 3, wherein the transmission apparatus is raised by a desired amount so as to position the transmission apparatus on the target medium.   The irradiation spot forming apparatus according to claim 4, wherein the slider includes a molding surface part of which is continuously changed to face the target medium.   6. The irradiation spot forming apparatus according to claim 5, wherein the molding surface is formed by gray scale etching.   The slider crosses the incident light before reaching the first and second gratings, transmits the incident light to the first and second sliders through the slider. The irradiation spot formation apparatus of Claim 4.   The slider crosses the incident light before reaching the first and second gratings, transmits the incident light through the slider, and transmits the incident light to the first and second sliders. 6. The irradiation spot forming apparatus according to claim 5, wherein the incident light is used to change the incident light by a predetermined method before the incident light enters the first and second gratings.   2. The irradiation spot forming apparatus according to claim 1, wherein the lattice elements are substantially parallel, have various lengths, and are spaced from each other. Positioning a first grating and a second grating which are separated by a predetermined distance and which are composed of a plurality of grating elements;
Irradiating the first and second gratings with incident light having a characteristic wavelength greater than the predetermined distance, the irradiation causes the first and second gratings to re-radiate to a desired size and polarization on the target medium. An irradiation spot forming method characterized by forming a spot.   11. The irradiation spot forming method according to claim 10, wherein the spot size is smaller than a spot size formed by a solid portion having a similar size and shape instead of the first and second gratings. The method further includes attaching the first and second gratings to a movable transmission device, the movable transmission device comprising a lens structure, the lens structure including an integrated portion for collecting incident light. The condensed incident light becomes incident light that irradiates the first and second gratings, and the orientation of the first and second gratings is maintained with respect to the lens structure,
The method further includes moving the transmission device on the target medium to a desired position, and the irradiated first and second gratings create an irradiation spot having a desired spot size and polarization at a desired position. The irradiation spot forming method according to claim 10.   The method further includes attaching a slider to the transmission device on the same side facing the first and second gratings, wherein the slider is configured to move the target medium when the transmission device moves relative to the target medium. The irradiation spot forming method according to claim 12, wherein the transmission device is raised by a desired amount so as to position the transmission device.   The irradiation spot forming method according to claim 13, wherein the slider includes a molding surface part of which is continuously changed to face the target medium.   The irradiation spot forming method according to claim 14, wherein the molding surface is formed by gray scale etching. An amplification antenna comprising a first grating and a second grating is provided, and the first and second gratings are irradiated with incident light having a specific wavelength, and the first and second gratings include a plurality of gratings. And the first and second gratings are separated by a distance less than the characteristic wavelength, and the grating antenna emits light that forms a desired size and a spot size of polarization on the target medium. Re-radiating,
The transmission device further includes a movable transmission device, and the transmission device includes a lens structure, and the lens structure includes an integrated portion that collects incident light, and the collected incident light is the first and second Incident light that irradiates the grating, and the orientation of the first and second gratings is maintained with respect to the lens structure,
A read and write circuit, wherein the write circuit sets the polarization of the target medium in the spot, and the read circuit reads the polarization of the target medium in a predetermined area. And writing optical device.   A slider, wherein the slider is attached to the transmission device on the same side facing the first and second gratings, and the slider is moved when the transmission device is moved relative to the target medium; 17. The read and write optical device of claim 16, wherein the transmission device is raised by a desired amount to position the transmission device on the target medium.   The reading and writing optical apparatus according to claim 17, wherein the slider includes a molding surface facing the target medium.   The reading and writing optical apparatus according to claim 18, wherein the molding surface is formed by gray scale etching.   The reading and writing optical apparatus according to claim 18, wherein the slider and the lens structure are formed on a single substrate.   The reading and writing optical apparatus according to claim 18, wherein the target medium is an optical recording medium.   The reading and writing optical apparatus according to claim 18, wherein the target medium is a magnetic recording medium.   19. A read and write optical apparatus according to claim 18, wherein the incident light is provided by a VIXEL chip. A gray scale mask having a pattern of a predetermined molding surface is developed, and the predetermined molding surface is selected to produce a slider that sufficiently raises the writing / reading device to obtain a predetermined distance on the storage medium. ,
Place the photoresist on the substrate,
Exposing the photoresist to light through the grayscale mask until the photoresist is developed;
Removing undeveloped photoresist to produce an indication of the predetermined molding surface pattern with developed photoresist;
Etching the developed photoresist and the substrate to form a molded surface corresponding to the predetermined molded surface pattern on the substrate.   25. The method of claim 24, wherein the method produces a slider having at least one surface that varies continuously in height. Prepare a mold with a concavo-convex shape opposite to the predetermined molding surface pattern,
Prepare a curable material,
Placing the curable substance in the mold,
In order to cure the curable substance by the mold that creates a molding surface having a shape corresponding to the predetermined molding surface pattern on the curable substance, and the predetermined molding surface obtains a predetermined distance on the storage medium. A method of manufacturing a slider, characterized in that it is selected to manufacture a slider that raises the writing / reading device sufficiently.   27. The method of claim 26, wherein the method produces a slider having at least one surface that varies continuously in height. Prepare a mold with a concavo-convex shape opposite to the predetermined molding surface pattern,
Prepare the molding material,
Placing the molding material in the mold,
The molding material is embossed by the mold to create a molding surface having a shape corresponding to the predetermined molding surface pattern on the molding material, and the predetermined molding surface is written on the storage medium to obtain a predetermined distance. A method of manufacturing a slider, characterized in that it is selected to manufacture a slider that raises the reader sufficiently.   29. The method of claim 28, wherein the method produces a slider having at least one surface that varies continuously in height.

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