Patent US5134426A successfully refreshed from Google Patents.
US5134426A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical device for generating pattern having uniform light intensity distribution
Assignee: Hitachi Ltd
•
Filing: 1990-03-29
•
Granted: 1992-07-28
•
Expires: 2010-03-29
Abstract
Abstract An optical device for illuminating an object with a rectangular pattern having a uniform light intensity distribution includes n (n>/=1) polarization separating elements which a laser beam emitted from a laser source enters and each of which separates the laser beam into two beams in two directions. The angle of separation by the polarization separating element is set to be 2(n-1) times of the smallest one of the separation angles of the polarization separating elements used. At least one quarter-wave or half-wave plate is combined with the polarization separating elements. An imaging lens is provided for forming 2n beam spots on the object such as an optical laser disk plate.
Inventors
- 👤 Keiji Kataoka
- 👤 Seiji Yonezawa
- 👤 Toshio Kaneko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:06
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1356; G02; G02B; G02B27/00; G02B27/28; G02B27/283; G11B7/1398
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
103 words
An optical device comprising: a laser source for generating a laser beam; an object to be illuminated; n (n≧1) polarization separating elements which the laser beam from said laser source enters, each of said polarization separating elements separating the laser beam into two beams in two directions, the angle of separation by the polarization separating element being set to be 2.sup.(n-1) times of the smallest one of the separation angles of the polarization separating elements used; at least one 1/m-wave plate combined with said polarization separating elements; and an imaging lens for forming 2 n beam spots on said object to be illuminated.
Claim 2
Dependent Claim
103 words
An optical device comprising: a laser source for generating a laser beam; an object to be illuminated; n (n≧1) polarization separating elements which the laser beam from said laser source enters, each of said polarization separating elements separating the laser beam into two beams in two directions, the angle of separation by the polarization separating element being set to be 2.sup.(n-1) times of the smallest one of the separation angles of the polarization separating elements used; at least one 1/m-wave plate combined with said polarization separating elements; and an imaging lens for forming 2 n beam spots on said object to be illuminated.
Claim 3
Dependent Claim
53 words
An optical device according to Claim 1, wherein in order that adjacent ones of said 2 n beam spots partially overlap each other, said separation angle is set to satisfy a relation of a/p>0.5 wherein a is the degree of spreading of a light spot and p is the pitch of light spots.
Claim 4
Dependent Claim
17 words
An optical device according to Claim 1, wherein m in said 1/m-wave plate is 4 and/or 2.
Claim 5
Dependent Claim
16 words
An optical device according to Claim 1, wherein said polarization separating element includes a Wollaston prism.
Claim 6
Dependent Claim
16 words
An optical device according to Claim 1, wherein said polarization separating element includes a Rochen prism.
Claim 7
Dependent Claim
16 words
An optical device according to Claim 1, wherein said polarization separating element includes a Senarmont prism.
Claim 8
Independent Claim
125 words
A device for detecting the shape and/or the number of particles, comprising: a laser source for generating a laser beam; particles as an object to be illuminated; n (n≧1) polarization separating elements which the laser beam from said laser source enters, each of said polarization separating elements separating the laser beam into two beams in two directions, the angle of separation by the polarization separating element being set to be 2.sup.(n-1) times of the smallest one of the separation angles of the polarization separating elements used; at least one 1/m-wave plate combined with said polarization separating elements; an imaging lens for forming 2 n beam spots and illuminating said particles with said beam spots; and light detecting means for detecting light reflected from said particles.
Claim 9
Independent Claim
125 words
A device for detecting the shape and/or the number of particles, comprising: a laser source for generating a laser beam; particles as an object to be illuminated; n (n≧1) polarization separating elements which the laser beam from said laser source enters, each of said polarization separating elements separating the laser beam into two beams in two directions, the angle of separation by the polarization separating element being set to be 2.sup.(n-1) times of the smallest one of the separation angles of the polarization separating elements used; at least one 1/m-wave plate combined with said polarization separating elements; an imaging lens for forming 2 n beam spots and illuminating said particles with said beam spots; and light detecting means for detecting light reflected from said particles.
Claim 10
Independent Claim
116 words
A device for recording and/or reproducing information on/from an optical recording medium, comprising: a laser source for generating a laser beam; an optical recording medium as an object to be illuminated; n (n≧1) polarization separating elements which the laser beam from said laser source enters, each of said polarization separating elements separating the laser beam into two beams in two directions, the angle of separation by the polarization separating element being set to be 2.sup.(n-1) times of the smallest one of the separation angles of the polarization separating elements used; at least one 1/m-wave plate combined with said polarization separating elements; and an imaging lens for forming 2 n beam spots on said optical recording medium.
Claim 11
Independent Claim
116 words
A device for recording and/or reproducing information on/from an optical recording medium, comprising: a laser source for generating a laser beam; an optical recording medium as an object to be illuminated; n (n≧1) polarization separating elements which the laser beam from said laser source enters, each of said polarization separating elements separating the laser beam into two beams in two directions, the angle of separation by the polarization separating element being set to be 2.sup.(n-1) times of the smallest one of the separation angles of the polarization separating elements used; at least one 1/m-wave plate combined with said polarization separating elements; and an imaging lens for forming 2 n beam spots on said optical recording medium.
Claim 12
Dependent Claim
23 words
An optical device according to claim 1, wherein the optical device enables generation of a pattern having a substantially uniform light intensity distribution.
Claim 13
Dependent Claim
55 words
An optical device according to claim 1, wherein the optical device enables detection of at least one of a shape and number of particles, the object to be illuminated being the particles, the imaging lens illuminating the particles with the beam spots, and further comprising light detecting means for detecting light reflected from the particles.
Claim 14
Dependent Claim
44 words
An optical device according to claim 1, wherein the optical device enables at least one of recording and reproduction of information on/from an optical recording medium as the object to be illuminated, the imaging lens forming the beam spots on the optical recording medium.
References Cited (Backward Citations)
US4413342A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-28 | 1996-01-27 | 1996-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-28 | 2000-01-27 | 2000-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-28 | 2004-01-27 | 2004-07-28 | $7700.00 | Window Closed / Lapsed |