US5930219A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical pickup device for discs of varying characteristics
Assignee: LG Electronics Inc
•
Filing: 1996-12-26
•
Granted: 1999-07-27
•
Expires: 2016-12-26
Abstract
Abstract An improved optical pickup apparatus which is capable of reading data from and writing the same in discs each having a different recording density and thickness by using only one optical pickup apparatus by controlling the numerical aperture of an objective lens by using a Liquid Crystal Shutter (LCS) and a diffraction hologram. The apparatus includes a diffraction direction conversion member for converting a diffraction direction of a beam from a laser diode, which beam advances toward an optical disc, a diffraction member for selectively diffracting the beam passed through the diffraction direction conversion member in accordance with a diffraction state, and an objective lens for focusing the beam from the diffraction member on the optical disc.
Inventors
- 👤 Young Sik Kim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:22
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/12; G11B7/135; G11B7/1353; G11B7/1365; G11B7/1369; G11B7/139; G11B2007/0003; G11B2007/0006; G11B7/1372; G11B2007/13727; G11B7/002; G11B7/0037
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
65 words
An optical pickup apparatus, comprising: generating means for generating a beam toward an optical disc; varying means for varying a polarization direction of the beam advancing toward the optical disc, using a voltage signal; diffracting means for selectively diffracting the beam from the varying means to impinge the beam on the optical disc; and detecting means for detecting a reflected beam from the optical disc.
Claim 2
Dependent Claim
65 words
An optical pickup apparatus, comprising: generating means for generating a beam toward an optical disc; varying means for varying a polarization direction of the beam advancing toward the optical disc, using a voltage signal; diffracting means for selectively diffracting the beam from the varying means to impinge the beam on the optical disc; and detecting means for detecting a reflected beam from the optical disc.
Claim 3
Dependent Claim
22 words
The apparatus of claim 1, wherein the diffracting means includes an objective lens having a diffraction grating formed on one side thereof.
Claim 4
Dependent Claim
16 words
The apparatus of claim 1, wherein the diffracting means is integrally formed on the varying means.
Claim 5
Dependent Claim
32 words
The apparatus of claim 1, wherein the diffracting means includes an objective lens having at least one circular blocking film formed on a portion of the objective lens for decreasing spherical aberration.
Claim 6
Dependent Claim
35 words
The apparatus of claim 1, wherein the varying means includes: a pair of transparent substrates; a pair of transparent electrodes formed between the transparent substrates; and a liquid crystal layer formed between the transparent electrodes.
Claim 7
Dependent Claim
13 words
The apparatus of claim 5, wherein the diffracting means includes a diffraction hologram.
Claim 8
Dependent Claim
39 words
The apparatus of claim 1, wherein the varying means includes a liquid crystal shutter having a liquid crystal therein for changing the polarization direction of the beam passing therethrough, depending on whether or not the voltage is applied thereto.
Claim 9
Dependent Claim
33 words
The apparatus of claim 6, wherein one of the transparent electrodes is formed to be circular and a diffraction pattern of the diffraction hologram is formed to be one of square and circular.
Claim 10
Dependent Claim
33 words
The apparatus of claim 6, wherein one of the transparent electrodes is formed to be one of square and circular, and a diffraction pattern of the diffraction hologram is formed to be circular.
Claim 11
Dependent Claim
17 words
The apparatus of claim 1, wherein the diffracting means includes a grating having a variable index modulation.
Claim 12
Dependent Claim
32 words
The apparatus of claim 1, wherein a diffraction angle θd of the beam which is made incident on the diffracting means is less than an angle θc of the total reflection condition.
Claim 13
Dependent Claim
32 words
The apparatus of claim 1, wherein a diffraction angle θd of the beam which is made incident on the diffracting means is greater than an angle θc of the total reflection condition.
Claim 14
Dependent Claim
24 words
The apparatus of claim 12, wherein the diffracting means includes a diffraction pattern which is larger than the size of the beam passing therethrough.
Claim 15
Dependent Claim
18 words
The apparatus of claim 1, wherein a diffraction angle θd of the diffracting means is more than 0.5°.
Claim 16
Dependent Claim
22 words
The apparatus of claim 7, wherein the diffracting means includes a diffraction hologram formed on one side of the liquid crystal shutter.
Claim 17
Dependent Claim
63 words
The apparatus of claim 1, wherein the generating means includes: a laser diode, a beam splitter for reflecting the beam from the laser diode and transmitting the reflected beam from the optical disc onto the detecting means, a collimator lens for transmitting the beam from the beam splitter, and a prism for reflecting the beam from the collimator lens toward the varying means.
Claim 18
Dependent Claim
21 words
The apparatus of claim 16, wherein the detecting means includes a photodetector for detecting the beam transmitted through the beam splitter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-07-26 | 2003-01-25 | 2003-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-07-26 | 2007-01-25 | 2007-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-07-26 | 2011-01-25 | 2011-07-27 | $7700.00 | Window Closed / Lapsed |