Method and apparatus for coupling an optical lens to a disk through a coupling medium having a relatively high index of refraction

• US 6,236,634 B1
• Filed: 08/11/2000
• Issued: 05/22/2001
• Est. Priority Date: 08/26/1996
• Status: Expired due to Fees

• Current Assignee: Digital Papyrus Corporation
• Original Assignee: Digital Papyrus Corporation
• Inventors: Ho, Easen, Lee, Neville K. S., Berg, John S.
• Primary Examiner(s): EDUN, MUHAMMAD N
• Application Number:
  US09/636,492
• Time in Patent Office: 284 Days
• Field of Search: 369/112.01, 369/112.02, 369/112.08, 369/112.23, 369/112.24, 369/44.12, 369/44.11, 369/44.14, 369/44.17, 369/44.18, 369/44.19, 369/44.22, 369/44.23
• US Class Current: 369/112.23
• CPC Class Codes: G11B 7/122 Flying-type heads, e.g. analogous to Winchester type in magnetic recording
• CPC Class Codes: G11B 7/1374 Objective lenses optical objectives per se G02B9/00
• CPC Class Codes: G11B 7/24 Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the arrangement of information on the carrier G11B7/007

Abstract

In one aspect, an optical recording system including an optical recording medium; a light source; a focusing lens that focuses light generated by the light source to form a focused beam of light directed toward the recording medium; and a coupling medium disposed between the lens and at least one portion of the optical recording medium, the coupling medium being transparent and having a refractive index greater than one. The coupling medium facilitates optical coupling between the lens and the recording medium. In another aspect, the coupling medium is disposed so that no air gap exists in the optical path between the lens and the recording medium. In another aspect, the exit surface of the lens is disposed at a distance from the recording medium that exceeds a distance that an evanescent wave of a high angle ray of the beam of light would travel after contacting air, but the system includes coupling means for coupling the ray of light from the lens to the recording medium. In another aspect, an optical recording medium is provided with at least one layer of fluid disposed atop the recording medium, the fluid being transparent and having a refractive index greater than one.

Claims

1. An optical recording system for recording on an optical recording medium, which processes light from a light source, the system comprising:

a focusing lens that focuses light generated by the light source to form a focused beam of light directed toward the recording medium;

a first coupling medium disposed between the focusing lens and the optical recording medium, the first coupling medium having a refractive index greater than one;

a second coupling medium disposed between the first coupling medium and at least one portion of the optical recording medium, the second coupling medium being transparent and having a refractive index greater than one, the second coupling medium being separable from both the recording medium and the first coupling medium;

wherein

the first coupling medium is a solid lens, and wherein the second coupling medium includes a fluid bearing that is disposed between and in physical contact with the solid lens and the recording medium; and

further comprising

a flying head to which the solid lens is mounted, the flying head being constructed and arranged to generate a force that compresses the fluid bearing between the solid lens and the recording medium.

2. The optical recording system of claim 1, wherein the flying head has a static bias that generates the force.

3. The optical recording system of claim 1, wherein the flying head has a tilt angle that results in the generation of the force.

4. The optical recording system of claim 3, wherein the flying head has an offset pivot axis that causes the tilt angle.

5. An optical recording system for recording on an optical recording medium, which processes light from a light source, the system comprising:

a focusing lens that focuses light generated by the light source to form a focused beam of light directed toward the recording medium;

a first coupling medium disposed between the focusing lens and the optical recording medium, the first coupling medium having a refractive index greater than one; and

a second coupling medium disposed between the first coupling medium and at least one portion of the optical recording medium, the second coupling medium being transparent and having a refractive index greater than one, the second coupling medium being separable from both the recording medium and the first coupling medium;

wherein the first coupling medium is a solid lens, and wherein the second coupling medium includes a fluid bearing that is disposed between and in physical contact with the solid lens and the recording medium; and

wherein

the solid lens includes means for maintaining the integrity of the fluid bearing despite relative movement between the solid lens and the record medium; and

a flying head to which the solid lens is mounted, the flying head being constructed and arranged to generate a force that compresses the fluid bearing between the solid lens and the recording medium.

6. An optical recording system for recording on an optical recording medium, which processes light from a light source, the system comprising:

a focusing lens that focuses light generated by the light source to form a focused beam of light directed toward the recording medium;

a first coupling medium disposed between the focusing lens and the optical recording medium, the first coupling medium having a refractive index greater than one; and

a second coupling medium disposed between the first coupling medium and at least one portion of the optical recording medium, the second coupling medium being transparent and having a refractive index greater than one, the second coupling medium being separable from both the recording medium and the first coupling medium;

wherein

the recording medium has a plurality of tracking grooves and a plurality of lands, and wherein the second coupling medium includes a fluid disposed in the plurality of grooves; and

wherein

at least one of the plurality of grooves comprises a recording area wherein information is recorded; and

wherein

the first coupling medium is a solid lens, wherein the focused beam of light exits the solid lens and passes through an optical path between the solid lens and the at least one portion of the recording medium, and wherein the second coupling medium is in direct physical contact with the solid lens and the at least one portion of the recording medium so that no air gap exists in the optical path.

7. An optical recording system for recording on an optical recording medium, which processes light from a light source, the system comprising:

a lens that is disposed between the light source and the recording medium, the lens having an exit surface from which the beam of light exits and passes through an optical path between the lens and the recording medium; and

a coupling medium disposed between the exit surface of the lens and at least one portion of the recording medium, the coupling medium being disposed between the lens and the at least one portion of the recording medium so that no air gap exists in the optical path;

wherein

the coupling medium comprises a fluid bearing; and

further comprising

a flying head to which the lens is mounted, the flying head being constructed and arranged to generate a force that compresses the fluid bearing between the lens and the recording medium.

8. The optical recording system of claim 7, wherein the flying head has a static bias that generates the force.

9. The optical recording system of claim 7, wherein the flying head has a tilt angle that results in generation of the force.

10. An optical recording system for recording on an optical recording medium having a plurality of recording areas on which information can be recorded, and a light source that generates a beam of light, the system comprising:

a lens that is disposed between the light source and the recording medium, the lens having an exit surface from which the beam of light is directed toward the recording medium, the exit surface of the lens being disposed at an access distance from at least one of the plurality of recording areas when the optical recording system accesses the at least one of the plurality of recording areas, the access distance exceeding a distance that an evanescent wave of at least one high angle ray of the beam of light would travel after exiting the exit surface of the lens and contacting air;

coupling means for coupling the at least one high angle ray of the beam of light to the at least one of the plurality of recording areas; and

a flying head that supports the lens above the recording medium.

11. An optical recording system for recording on an optical recording medium having a plurality of recording areas on which information can be recorded, and a light source that generates a beam of light, the system comprising:

a lens that is disposed between the light source and the recording medium, the lens having an exit surface from which the beam of light is directed toward the recording medium, the exit surface of the lens being disposed at an access distance from at least one of the plurality of recording areas when the optical recording system accesses the at least one of the plurality of recording areas, the access distance exceeding a distance that an evanescent wave of at least one high angle ray of the beam of light would travel after exiting the exit surface of the lens and contacting air; and

coupling means for coupling the at least one high angle ray of the beam of light to the at least one of the plurality of recording areas;

wherein

the optical recording medium has a plurality of tracking grooves and a plurality of lands; and

wherein

the at least one of the plurality of recording areas is disposed within one of the plurality of tracking grooves; and

wherein the at least one of the plurality of recording areas is disposed within the one of the plurality of tracking grooves at a depth that exceeds the distance that the evanescent wave of the at least one high angle ray of the beam of light would travel after exiting the exit surface of the lens and contacting air; and

further comprising

a flying head that supports the lens above the recording medium.

12. A method of operating an optical recording system that includes an optical recording medium having a plurality of recording areas on which information can be recorded, a light source that generates a beam of light, and a lens that is disposed between the light source and the recording medium, the lens having an exit surface from which the beam of light exits the lens and is directed toward the recording medium, the method comprising the steps of:

(A) disposing the exit surface of the lens at a distance from at least one of the plurality of recording areas that exceeds a distance that an evanescent wave of at least one high angle ray of the beam of light would travel after exiting the exit surface of the lens and contacting air; and

(B) coupling the at least one high angle ray of the beam of light from the exit surface of the lens to the at least one of the plurality of recording areas;

wherein

the optical recording system includes a flying head that supports the lens; and

wherein step (A) includes a step of flying the flying head at a height wherein the distance from the exit surface of the lens to the at least one of the plurality of recording areas exceeds the distance that the evanescent wave of the at least one high angle ray of the beam of light would travel after exiting the exit surface of the lens and contacting air; and

wherein the optical recording system includes a flying head that supports the lens;

wherein step (A) includes a step of flying the flying head at a height wherein the distance from the exit surface of the lens to each of the plurality of recording areas exceeds the distance that the evanescent wave of the at least one high angle ray of the beam of light would travel after exiting the exit surface of the lens and contacting air; and

wherein step (B) includes a step of coupling the at least one high angle ray of the beam of light from the exit surface of the lens to each of the plurality of recording areas.