JP2001517851A - Optical head and method of configuring the optical head - Google Patents

Abstract

(57) Abstract: An optical head 100 that executes optical data calculation on a medium 118 includes a slider body 154 and at least one lens 150. An aperture stop 158 that blocks transmission of light is located between the slider body 154 and the lens 150. Aperture stop 158 includes an opaque layer that defines a transparent area.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head. In particular, the invention relates to a floating optical head.

Optical data storage devices access data by focusing a laser beam or other light source on the data surface of a medium and analyzing the light reflected from or transmitted through the medium. Generally, data is stored on an optical storage device in the form of marks supported on the surface of the medium and detected using reflected laser beams.

[0003] Compact disks, widely used for storing computer programs, music and video, are a type of optical data storage device. Typically, the compact disc is permanently recorded during manufacture by etching the surface of the compact disc. Another type of optical device is write once, read multiple (WORM), where the user can permanently write information to a blank disc.
Device. Other types of devices include, for example, phase change and magneto-optic (MO)
) Erasable like a device. The phase change device detects data by detecting a change in reflectivity. The MO device reads the data by measuring the rotation of the deflection of the incident light beam due to the magnetic state of the storage medium.

[0004] The foregoing apparatus requires that a beam of light be focused on the data surface of the disk.
The storage density is determined not only by the size of the markings on the data surface, but also by the size (ie, resolution) of the beam focused on the surface. Generally, the optics used to focus the beam onto the surface fall into two groups: those with floating heads and those without floating heads. In devices that do not use a floating head, a portion of the optical device typically moves radially above the disk to follow the track of the disk. The moving part of the optic is supported by a physical structure that extends above the disk. In an apparatus with a floating head, the optics in the head are actually supported by a thin layer of fluid, typically air, which rotates with the disk. By floating over this thin layer of fluid, the optics of the head are located very close to the surface.

In both devices, an objective lens is used to focus the light beam onto a spot on the disk. In devices with a floating head, the objective is used in conjunction with a solid immersion lens or SIL. The objective lens sets the beam to S
Focused in the IL, SILs reduce the beam spot size by shortening the wavelength that occurs when light passes through optically dense media. Since the SIL is located on the floating head, the SIL is located very close to the data plane, and thus the SIL
Are coupled to the disk surface via the dissipated wave.

In both devices, as the light beam passes through the objective, some of the light beam
Otherwise it forms a fringe field around the periphery of the focused beam.
In devices where the objective lens and the SIL do not float on media such as most compact disks, the objective lens may cover these fringes by coating the periphery of the objective with a material that reflects or absorbs light. Large enough that fields can be eliminated. Alternatively, a separate element can be inserted above the objective lens to block such extraneous light.

[0007] The above-described coating method requires that the objective lens used in the floating head be too small and hemispherical, so that it is difficult to properly align the mask for welding the material to the lens, so that the floating optical head is difficult to use. Cannot be used. Similarly, the individual components add too much weight to the head, so that the individual components cannot be added to the floating head to block extraneous light.

SUMMARY OF THE INVENTION An optical head for performing optical data operations on a medium includes a slider body and at least one lens. An aperture stop that blocks transmission of light rays is located between the slider body and the lens. The aperture stop includes an opaque layer surrounding a transparent area.

In a preferred embodiment, the aperture stop is welded directly to the slider body by photolithography. The transparent slider body allows the aperture stop to be aligned with features formed on the opposite surface of the slider body.

FIG. 1 is a side view of an optical storage device 98 according to the present invention. The optical module including the laser generates a beam of light 116 that is directed through a sealed optical path extending laterally from the optical module. The light beam 116 is directed toward the optical head 100 which focuses the beam onto a small spot on the disk.
It is reflected at 14. The disk 118 pivots about a central axis 120 and continuously brings a new data area under the spot of light rays generated by the optical head 100. Light rays incident on the disk 118 are reflected through the sealed optical path 112 and analyzed by a control module mounted on the optical module 108. Through such a process, the optical storage device 98 retrieves information stored on the disk 118.

The optical head 100 is supported by a suspension assembly 102 supported by an arm 104. The arm 104, the optical module 108 and the sealed optical path 112 are all comprised of a spindle 106 rotating about a central axis 110.
Supported by As the spindle 106 rotates, the head 100
Has been moved to a different radial position across the disk 118 and the sealed optical path 112 has been rotated to remain aligned with the optical head 100.

FIG. 2 is a schematic view of optical equipment in the optical device shown in FIG. In the optical module 108, a laser diode 130 passes through the beam splitter 132 and the relay lens 134, is reflected by the galvo mirror 16, is converted into a parallel light by the image forming lens 138, is reflected by the curved mirror 114, and is reflected by the optical head 100. A light beam to be focused on the optical disk 118 is generated. The light beam is reflected by the optical disk 118, returns through the head 100, is reflected by the curved mirror 114, passes through the image forming lens 138, is reflected by the galvo mirror 136, and is reflected by the relay lens 13
4 and is reflected by the beam splitter 132 to form the Wollaston prism 1
The light passes through 40 and becomes focused before or after the plane 142 of the detector. In a preferred embodiment, the galvo mirror 136 can be deflected by an electric current to change the position of the light spot on the disk. For this reason, the light spot is finely controlled so that the light spot can be moved over several tracks on the disk without moving the optical head 100.

FIG. 3 is a side view of the optical head 100 shown in FIG. Light rays 116 enter an objective lens supported by standoffs 152 on a transparent slider body 154. The light beam 116 is focused by the objective lens 150 through the cap lens 156 adhered to the slider body 154 by an adhesive. Cap lens 156
, The adhesive, and the slider body 154 to form a solid immersion lens. Below the periphery of the cap lens 156, an opaque layer forming the aperture stop 158 is located. The opaque layer of the aperture stop 158 surrounds a transparent area that allows the light rays 116 to enter and pass through the slider body 154. The objective lens 150, the cap lens 156, and the aperture stop 158 work together to form a small light spot on the bottom surface of the slider body 154. Aperture stop 158
Improves the spot resolving power by blocking external rays around the objective lens 150 from passing through the slider body 154.

FIG. 4 is an enlarged view of a part of the aperture stop 158 and the cap lens 156. FIG.
The aperture stop 158 is preferably formed from a layer of material directly welded to the slider body 154, as shown in FIG. Further, the cap lens 156 is mounted on the slider body 1.
It is bonded to the aperture 54 and the aperture stop 150 by an adhesive layer 160. Adhesive layer 160
It should be noted that the thickness of the aperture affects the absorption and reflection of light rays incident on the aperture stop 158. It is preferred that light absorption be maximized and that light rays entering aperture stop 158 be minimized in reflection. In the preferred embodiment where the aperture stop 158 was formed from chrome, reflection was minimized for a 450 nanometer adhesive layer measured from the top of the aperture stop 158 to the bottom of the cap lens 156.

FIG. 5 shows an objective lens 150, an aperture stop 158 and a slider body 154.
FIG. 3 is a top view of the optical head 100. FIG. 5 also extends from the bottom of the slider body 154 and is formed as a piece of material of the slider body. Preferably, the topography formation 162 is located in the center of the aperture stop 158 and the objective lens 150 and is used as a reference point for positioning a mask for forming the aperture stop 158 on the slider body 154. The outer perimeter of the aperture stop 158 can then be used to position the stun-off 152 with respect to the center of the aperture stop 158. In that position, the standoffs 152 provide an excellent starting position for positioning the objective lens 150. Precise positioning of the objective lens 150 is achieved by passing the light beam through the optical head 100 and moving the objective lens until the spot at the bottom of the slider is optimal. The aperture stop 158 speeds up this process by significantly degrading the spot if the objective lens is offset with respect to the center of the aperture stop 158.

FIGS. 6A to 6D show various stages of the optical head 100 during the manufacturing process of the optical head. In the first step, shown in FIG. 6A, the slider body 154 is coated with an opaque layer of material 170, which is preferably an optically reflective material such as chrome. 100 layers of chrome
Preferably, it is 0 Å. In FIG. 6B, a second step of the method includes coating the opaque layer 170 with a photoresist 172. In FIG. 6C, the photoresist 172 has been patterned using a shadow mask, and unnecessary photoresist material has been removed to remove the opaque layer 17.
Developed to leave a ring 174 patterned to zero. Protection ring 1
Portions of the opaque layer 170 that are not protected by 74 are removed, and FIG.
Leave aperture stop 158 covered by protective ring 174 as shown. 6 (5), the protection ring 174 has been removed, leaving the aperture stop 158 exposed.

In FIG. 6 (6), an adhesive 160 is applied to the aperture stop 158 and a portion of the slider main body 154 located in the central portion of the aperture stop 158. A cap lens 156 is attached to the top of the adhesive 160 and joined to the slider body 154 and the aperture stop 158. 6 (7), a standoff 152 in the form of a ring is aligned with the outer periphery of the aperture stop 158 and is joined to the slider body 154. In the final stage of this step shown in FIG.
50 is mounted on the standoff 152 to optimize the light spot formed at the bottom of the slider body 154, centered on the center of the aperture stop 158.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. .

[Brief description of the drawings]

FIG. 1 is a side view of an optical device according to the present invention.

FIG. 2 is a schematic diagram of an optical apparatus in the optical device shown in FIG.

FIG. 3 is a side view of the optical head shown in FIG.

FIG. 4 is an enlarged side view of a part of the head shown in FIG. 3;

FIG. 5 is a top view of the head shown in FIG. 1;

6 (1) to (8) are side views of the head shown in FIG. 1 during various stages in the manufacture of the optical head.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventors Al-Jumaily, Chanim, A. United States Minnesota, Minneapolis, Pierce Street N, E, 4650 (72) Inventors Gage, Edward, Sea United States Minnesota, Apple Valley, Flint Wood Court 14050 (72) Inventors Swanson, Lori, Gee Minnesota, Minneapolis, Minneapolis, CAbel Avenue South 9701 F-term (reference) 5D119 AA11 AA22 CA06 JA44 JA59 JC03 MA06 NA05

Claims (13)

[Claims] 1. An optical head for performing optical data operations on a medium, comprising: a slider positionable at a number of positions on the medium; a slider coupled to the slider for condensing a light beam and a light beam on the medium. An optical head comprising light control means for restricting transmission of light. 2. The optical head according to claim 1, wherein the light beam control means includes a lens, and an aperture stop between the lens and a slider. 3. The optical head according to claim 2, wherein the lens is a cap lens. 4. The optical head according to claim 3, wherein the aperture stop is an opaque layer that defines a transparent area. 5. The optical head according to claim 4, wherein the cap lens is joined to a part of the opaque layer by an adhesive. 6. The optical head according to claim 5, wherein the adhesive contacts the slider in the transparent area. 7. The optical head according to claim 4, wherein said opaque layer is made of an optically reflective material. 8. The opaque layer is made of chrome.
An optical head according to item 1. 9. The optical head according to claim 3, further comprising an objective lens, and a cap lens between the objective lens and the aperture stop. 10. A method of constructing an optical head, comprising: configuring a slider body; forming an opaque layer having an aperture on the slider body; wherein the opaque layer is between a lens system and the slider body. Assembling the lens system to come. 11. The opaque layer is formed by photolithography and the opaque layer is aligned on the slider body to a feature found on the side of the slider body opposite the opaque layer. The method according to claim 10, wherein 12. The method according to claim 12, wherein the step of assembling the lens system comprises: joining a cap stand, which is aligned on the slider body using the outer periphery of the opaque layer, to the slider body; Joining to the substrate. 13. The method of claim 12, wherein assembling the lens system further comprises bonding a cap lens to the opaque layer with an adhesive.