US5245491A — Magneto-optical head employing optical fiber conn…

Claim 1

Independent Claim 124 words

An optical fiber type magneto-optical head comprising: first optical means for condensing a polarized light beam and leading the light beam into a polarization-maintaining optical fiber; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording film; a detector for detecting through the optical fiber light reflected from the magnetic recording film with a change in polarized state; and an azimuth rotator through which there is transmitted light passing between the second optical means and the optical fiber, the azimuth rotator being designed so that the angle of optical rotation upon one pass therethrough is θk/2±n·45° where θk/2: the Kerr rotation angle of the magnetic recording film, and n=0, 1, 2, . . . .

Claim 2

Dependent Claim 124 words

An optical fiber type magneto-optical head comprising: first optical means for condensing a polarized light beam and leading the light beam into a polarization-maintaining optical fiber; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording film; a detector for detecting through the optical fiber light reflected from the magnetic recording film with a change in polarized state; and an azimuth rotator through which there is transmitted light passing between the second optical means and the optical fiber, the azimuth rotator being designed so that the angle of optical rotation upon one pass therethrough is θk/2±n·45° where θk/2: the Kerr rotation angle of the magnetic recording film, and n=0, 1, 2, . . . .

Claim 3

Dependent Claim 25 words

The optical fiber type magneto-optical head as set forth in claim 1, wherein the azimuth rotator comprises a Faraday element comprising an optically active substance.

Claim 4

Dependent Claim 21 words

The optical fiber type magneto-optical head as set forth in claim 1, wherein the azimuth rotator comprises a reflection-type azimuth rotator.

Claim 5

Dependent Claim 23 words

The optical fiber type magneto-optical head as set forth in claim 3, wherein the reflection-type azimuth rotator also functions as a tracking mirror.

Claim 6

Dependent Claim 36 words

The optical fiber type magneto-optical head as set forth in claim 1, wherein the second optical means comprises a focusing lens, and a collimating lens is disposed between the azimuth rotator and the polarization-maintaining optical fiber.

Claim 7

Dependent Claim 45 words

The optical fiber type magneto-optical head as set forth in claim 1, wherein the second optical means comprises a focusing lens, and the emergence end of the polarization-maintaining optical fiber is located further from the focusing lens than the focal point of the focusing lens.

Claim 8

Dependent Claim 66 words

The optical fiber type magneto-optical head as set forth in claim 1, wherein the head includes a movable portion and a stationary portion, with the second optical means and the azimuth rotator forming a part of the movable portion and the first optical means forming a part of the stationary portion, and the polarization-maintaining optical fiber is disposed between the movable portion and the stationary portion.

Claim 9

Dependent Claim 54 words

The optical fiber type magneto-optical head as set in claim 1, wherein the head includes a plurality of movable portions and a plurality of stationary portions, the movable portions being each disposed between adjacent ones of a plurality of magneto-optic disks stacked one above another so as to collectively constitute a stack-type disk device.

Claim 10

Dependent Claim 30 words

The optical fiber type magneto-optical head as set forth in claim 1, wherein the principal direction of the polarization-maintaining optical fiber coincides with the principal direction of the azimuth rotator.

Claim 11

Dependent Claim 168 words

An optical fiber type magneto-optical head comprising: a laser light source; a polarizer for linearly polarizing laser light emitted from the laser light source; first optical means for condensing a polarized light beam emerging from the polarizer; a polarization-maintaining optical fiber, into which the polarized light beam is led while being condensed by the first optical means; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording film; an azimuth rotator disposed between the second optical means and the optical fiber; a beam splitter for branching light reflected from the magnetic recording film with a change in polarized state and returned through the azimuth rotator and the optical fiber; and a detector for detecting the reflected light branched by the beam splitter, wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is θk/2±n·45° where θk/2: the Kerr rotation angle of the magnetic recording film, n=0, 1, 2, . . . .

Claim 12

Dependent Claim 168 words

An optical fiber type magneto-optical head comprising: a laser light source; a polarizer for linearly polarizing laser light emitted from the laser light source; first optical means for condensing a polarized light beam emerging from the polarizer; a polarization-maintaining optical fiber, into which the polarized light beam is led while being condensed by the first optical means; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording film; an azimuth rotator disposed between the second optical means and the optical fiber; a beam splitter for branching light reflected from the magnetic recording film with a change in polarized state and returned through the azimuth rotator and the optical fiber; and a detector for detecting the reflected light branched by the beam splitter, wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is θk/2±n·45° where θk/2: the Kerr rotation angle of the magnetic recording film, n=0, 1, 2, . . . .

Claim 13

Dependent Claim 30 words

The optical fiber type magneto-optical head as set forth in claim 10, wherein the principal direction of the polarization-maintaining optical fiber coincides with the principal direction of the azimuth rotator.

Claim 14

Dependent Claim 164 words

An optical fiber type magneto-optical head comprising: a laser light source; a polarization beam splitter for converting laser light emitted from the laser light source into a linearly polarized light beam; first optical means for condensing the polarized light beam emerging from the polarization beam splitter; a polarization-maintaining optical fiber into which the condensed, polarized light beam is led; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording film; an azimuth rotator disposed between the second optical means and the optical fiber; and a detector for detecting light reflected from the magnetic recording film with a change in polarized state, returned through the azimuth rotator and the optical fiber and branched by the polarization beam splitter; wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is θk/2±n·45° where θk/2: the Kerr rotation angle of the magnetic recording film, and, n=0, 1, 2, . . . .

Claim 15

Dependent Claim 164 words

An optical fiber type magneto-optical head comprising: a laser light source; a polarization beam splitter for converting laser light emitted from the laser light source into a linearly polarized light beam; first optical means for condensing the polarized light beam emerging from the polarization beam splitter; a polarization-maintaining optical fiber into which the condensed, polarized light beam is led; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording film; an azimuth rotator disposed between the second optical means and the optical fiber; and a detector for detecting light reflected from the magnetic recording film with a change in polarized state, returned through the azimuth rotator and the optical fiber and branched by the polarization beam splitter; wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is θk/2±n·45° where θk/2: the Kerr rotation angle of the magnetic recording film, and, n=0, 1, 2, . . . .

Claim 16

Dependent Claim 145 words

An optical fiber type magneto-optical head comprising: first optical means for condensing a polarized light beam and leading the light beam into a polarization-maintaining optical fiber; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording film; an azimuth rotator through which there is transmitted light passing between the second optical means and the optical fiber; a beam splitter for branching light reflected from the magnetic recording film with a change in polarized state and returned through the azimuth rotator and the optical fiber; a polarization beam splitter for branching into an s-polarized wave and a p-polarized wave the reflected light branched by the beam splitter; and detectors for detecting the s-polarized wave and the p-polarized wave, respectively, wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is

Claim 17

Dependent Claim 145 words

An optical fiber type magneto-optical head comprising: first optical means for condensing a polarized light beam and leading the light beam into a polarization-maintaining optical fiber; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording film; an azimuth rotator through which there is transmitted light passing between the second optical means and the optical fiber; a beam splitter for branching light reflected from the magnetic recording film with a change in polarized state and returned through the azimuth rotator and the optical fiber; a polarization beam splitter for branching into an s-polarized wave and a p-polarized wave the reflected light branched by the beam splitter; and detectors for detecting the s-polarized wave and the p-polarized wave, respectively, wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is

Claim 18

Dependent Claim 10 words

+22. 5°±n·45°, where n=0, 1, 2, . . . .

Claim 19

Dependent Claim 10 words

+22. 5°±n·45°, where n=0, 1, 2, . . . .

Claim 20

Dependent Claim 182 words

An optical fiber type magneto-optical head of the differential type, comprising: a laser light source; a polarizer for linearly polarizing laser light emitted from the laser light source; first optical means for condensing a polarized light beam emerging from the polarizer; a polarization-maintaining optical fiber, into which the polarized light beam is led while being condensed by the first optical means; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording an azimuth rotator disposed between the second optical means and the optical fiber; a beam splitter for branching light reflected from the magnetic recording means with a change in polarized state and returned through the azimuth rotator and the optical fiber; a polarization beam splitter for branching into an s-polarized wave and a p-polarized wave the reflected light branched by the beam splitter; and detectors for detecting the s-polarized wave and the p-polarized wave, respectively, wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is +22.5°±n·45°, where n=0, 1, 2, . . . .

Claim 21

Dependent Claim 182 words

An optical fiber type magneto-optical head of the differential type, comprising: a laser light source; a polarizer for linearly polarizing laser light emitted from the laser light source; first optical means for condensing a polarized light beam emerging from the polarizer; a polarization-maintaining optical fiber, into which the polarized light beam is led while being condensed by the first optical means; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording an azimuth rotator disposed between the second optical means and the optical fiber; a beam splitter for branching light reflected from the magnetic recording means with a change in polarized state and returned through the azimuth rotator and the optical fiber; a polarization beam splitter for branching into an s-polarized wave and a p-polarized wave the reflected light branched by the beam splitter; and detectors for detecting the s-polarized wave and the p-polarized wave, respectively, wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is +22.5°±n·45°, where n=0, 1, 2, . . . .

Claim 22

Dependent Claim 29 words

The optical fiber type magneto-optical head as set forth in claim 14, wherein the principal direction of the polarization-maintaining optical fiber coincides with the principal direction of the polarizer.

Claim 23

Dependent Claim 182 words

An optical fiber type magneto-optical head of the differential type, comprising: a laser light source; a polarizer for linearly polarizing laser light emitted from the laser light source; first optical means for condensing a polarized light beam emerging from the polarizer; a polarization-maintaining optical fiber, into which the polarized light beam is led while being condensed by the first optical means; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording film; an azimuth rotator disposed between the second optical means and the optical fiber; a beam splitter for branching light reflected from the magnetic recording means with a change in polarized state and returned through the azimuth rotator and the optical fiber; a polarization beam splitter for branching into an s-polarized wave and a p-polarized wave the reflected light branched by the beam splitter; and detectors for detecting the s-polarized wave and the p-polarized wave, respectively, wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is +22.5°±n·45°, where n=1, 2, . . . .

Claim 24

Dependent Claim 182 words

An optical fiber type magneto-optical head of the differential type, comprising: a laser light source; a polarizer for linearly polarizing laser light emitted from the laser light source; first optical means for condensing a polarized light beam emerging from the polarizer; a polarization-maintaining optical fiber, into which the polarized light beam is led while being condensed by the first optical means; second optical means for focusing light emerging from the optical fiber into a beam spot on a magnetic recording film; an azimuth rotator disposed between the second optical means and the optical fiber; a beam splitter for branching light reflected from the magnetic recording means with a change in polarized state and returned through the azimuth rotator and the optical fiber; a polarization beam splitter for branching into an s-polarized wave and a p-polarized wave the reflected light branched by the beam splitter; and detectors for detecting the s-polarized wave and the p-polarized wave, respectively, wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is +22.5°±n·45°, where n=1, 2, . . . .

Claim 25

Dependent Claim 29 words

The optical fiber type magneto-optical head as set forth in claim 16, wherein the principal direction of the polarization-maintaining optical fiber coincides with the principal direction of the polarizer.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1996-09-13	1997-03-15	1997-09-14	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2000-09-13	2001-03-15	2001-09-14	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2004-09-13	2005-03-15	2005-09-14	$7700.00	Window Closed / Lapsed

Magneto-optical head employing optical fiber connected stationary and movable portions

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag