Patent US4212512A successfully refreshed from Google Patents.
US5050153A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor laser optical head assembly
Assignee: Individual
•
Filing: 1989-06-06
•
Granted: 1991-09-17
•
Expires: 2009-06-06
Abstract
Abstract An improved optical head for reading information recorded on a reflected medium. The optical head uses a hologram lens assembly having a transparent plate and a hologram lens, the transparent plate being obliquely positioned relative to a forward and a return beam paths. The transparent plate corrects beam aberrations in a laser beam emitted by a semiconductor laser on the forward beam path. The hologram lens diffracts the laser beam on the return beam path onto a photodetector. Both the transparent plate and the hologram lens add beam aberrations to the defracted laser beam on the return beam path for tracking purposes. The hologram lens assembly may also include a second hologram lens, preferably a three beam diffraction grating, for tracking purposes. The hologram lens and the diffraction grating may be located on the obliquely positioned transparent plate or on other transparent plates.
Inventors
- 👤 Wai-Hon Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:44
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1392; G11B7/08; G11B7/09; G11B7/094; G11B7/123; G11B7/1353; G11B7/1372; G11B7/1378; G11B7/0901; G11B7/0903; G11B7/0908; G11B7/0909
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
163 words
An optical head for reading information recorded on a reflective medium, comprising: a) a semiconductor laser for emitting a laser beam that travels along a forward beam path to the reflective medium, reflects off the reflective medium, and continues along a return beam path; b) a photodetector disposed along the return beam path for detecting the laser beam after the laser beam has reflected off the reflective medium; and c) a holographic lens assembly disposed along the forward and return beam paths, the assembly including: (i) a transparent plate positioned oblique to the beam paths, the transparent plate having a first and second surfaces; and (ii) a hologram lens structure; whereby the transparent plate corrects beam aberrations in the laser beam on the forward beam path, the hologram lens diffracts the laser beam onto the photodetector on the return beam path, and both the transparent plate and the holographic lens add beam aberrations to the diffracted laser beam on the return beam path.
Claim 2
Dependent Claim
163 words
An optical head for reading information recorded on a reflective medium, comprising: a) a semiconductor laser for emitting a laser beam that travels along a forward beam path to the reflective medium, reflects off the reflective medium, and continues along a return beam path; b) a photodetector disposed along the return beam path for detecting the laser beam after the laser beam has reflected off the reflective medium; and c) a holographic lens assembly disposed along the forward and return beam paths, the assembly including: (i) a transparent plate positioned oblique to the beam paths, the transparent plate having a first and second surfaces; and (ii) a hologram lens structure; whereby the transparent plate corrects beam aberrations in the laser beam on the forward beam path, the hologram lens diffracts the laser beam onto the photodetector on the return beam path, and both the transparent plate and the holographic lens add beam aberrations to the diffracted laser beam on the return beam path.
Claim 3
Dependent Claim
14 words
The optical head of claim 1 wherein the transparent plate is comprised of glass.
Claim 4
Dependent Claim
35 words
The optical head of claim 1 wherein the holographic lens assembly further includes a second transparent plate with a surface having the holographic lens structure being disposed on the surface of the second transparent plate.
Claim 5
Dependent Claim
17 words
The optical head of claim 1 wherein the beam aberrations corrected in the laser beam include astigmatism.
Claim 6
Dependent Claim
17 words
The optical head of claim 1 wherein the beam aberrations added to the laser beam include astigmatism.
Claim 7
Dependent Claim
13 words
The optical head of claim 1 wherein the photodetector is a quadrant photodetector.
Claim 8
Dependent Claim
16 words
The optical head of claim 1 wherein the hologram lens assembly further includes a diffraction grating.
Claim 9
Dependent Claim
14 words
The optical head of claim 7 wherein the photodetector is an eight segment photodetector.
Claim 10
Dependent Claim
19 words
The optical head of claim 1 further comprising an objective lens for focusing the laser beam onto the medium.
Claim 11
Dependent Claim
41 words
The optical head of claim 9 further comprising a mirror for reflecting the laser beam from the semiconductor laser to the objective lens on the forward beam path and from the reflective medium to the photodetector on the return beam path.
Claim 12
Dependent Claim
213 words
An optical head for reading information recorded on a reflective medium, comprising: a) a semiconductor laser for emitting a laser beam that travels along a forward beam path to the reflective medium, reflects off the reflective medium, and continues along a return beam path; b) a photodetector disposed along the return beam path for detecting the laser beam after the laser beam has reflected off the reflective medium; and c) a holographic lens assembly disposed along the forward and return beam paths, the assembly including: (i) a transparent plate positioned oblique to the beam paths, the transparent plate having a first and second surfaces; (ii) a first hologram lens structure for diffracting the laser beam into a plurality of beams; and (iii) a second hologram lens structure for diffracting the laser beam into a plurality of beams; whereby the first hologram lens structure diffracts the laser beam into a plurality of beams on the forward beam path, the transparent plate corrects beam aberrations in the laser beam on the forward beam path, the second hologram lens structure diffracts the laser beam onto the photodetector on the return beam path, and both the transparent plate and the second holographic lens structure add beam aberrations to the diffracted laser beam on the return beam path.
Claim 13
Dependent Claim
213 words
An optical head for reading information recorded on a reflective medium, comprising: a) a semiconductor laser for emitting a laser beam that travels along a forward beam path to the reflective medium, reflects off the reflective medium, and continues along a return beam path; b) a photodetector disposed along the return beam path for detecting the laser beam after the laser beam has reflected off the reflective medium; and c) a holographic lens assembly disposed along the forward and return beam paths, the assembly including: (i) a transparent plate positioned oblique to the beam paths, the transparent plate having a first and second surfaces; (ii) a first hologram lens structure for diffracting the laser beam into a plurality of beams; and (iii) a second hologram lens structure for diffracting the laser beam into a plurality of beams; whereby the first hologram lens structure diffracts the laser beam into a plurality of beams on the forward beam path, the transparent plate corrects beam aberrations in the laser beam on the forward beam path, the second hologram lens structure diffracts the laser beam onto the photodetector on the return beam path, and both the transparent plate and the second holographic lens structure add beam aberrations to the diffracted laser beam on the return beam path.
Claim 14
Dependent Claim
17 words
The optical head of claim 11 wherein the first hologram lens structure is a diffraction grating structure.
Claim 15
Dependent Claim
36 words
The optical head of claim 12 wherein the second holographic lens structure is positioned relative to the diffraction grating structure diffracting the laser beam on the return beam path around the diffraction grating onto the photodetector.
Claim 16
Dependent Claim
14 words
The optical head of claim 12 wherein the transparent plate is comprised of glass.
Claim 17
Dependent Claim
35 words
The optical head of claim 12 wherein the holographic lens assembly further includes a second transparent plate having a surface, the second holographic lens assembly being disposed on the surface of the second transparent plate.
Claim 18
Dependent Claim
15 words
The optical head of claim 15 wherein the transparent plates are parallel to each other.
Claim 19
Dependent Claim
16 words
The optical head of claim 15 wherein the transparent plates are not parallel to each other.
Claim 20
Dependent Claim
17 words
The optical head of claim 12 wherein the beam aberrations corrected in the laser beam include astigmatism.
Claim 21
Dependent Claim
17 words
The optical head of claim 12 wherein the beam aberrations added to the laser beam include astigmatism.
Claim 22
Dependent Claim
14 words
The optical head of claim 12 wherein the photodetector is an eight segment photodetector.
Claim 23
Dependent Claim
19 words
The optical head of claim 12 further comprising an objective lens for focusing the laser beam onto the medium.
Claim 24
Dependent Claim
41 words
The optical head of claim 21 further comprising a mirror for reflecting the laser beam from the semiconductor laser to the objective lens on the forward beam path and from the reflective medium to the photodetector on the return beam path.
References Cited (Backward Citations)
US4355858A
Cited
US4794585A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-09-16 | 1995-03-18 | 1995-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-16 | 1999-03-18 | 1999-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-16 | 2003-03-18 | 2003-09-17 | $7700.00 | Window Closed / Lapsed |