Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
113 words
An optical disk drive for use with an optical disk (36) comprising an optical media for data storage with a transparent protective coating, said optical disk drive including: means (22) for generating a light beam for reflection off the surface of the optical media of the disk; an objective lens (34) for focusing the light beam onto the optical media for a disk with a transparent protective coating having a first thickness; and characterised by compensation lens means (48, 50) selectively actuable in conjunction with the objective lens to focus the light beam onto the optical media of a disk with a transparent protective coating having a thickness different from said first thickness.
Claim 2
Dependent Claim
60 words
An optical disk drive according to claim 1 wherein the compensation lens means includes a compensator lens (48) containing a quantity of liquid crystals (78) and means (80, 82, 84, 86) for applying a correction signal to the liquid crystals for altering a refractive index of the liquid crystals to eliminate wavefront aberration at the surface of the optical media.
Claim 3
Dependent Claim
62 words
An optical disk drive according to claim 2, wherein the compensator leans includes: transparent means (70, 72, 88, 90) for containing the liquid crystals; means for aligning (74, 76) the liquid crystals to change an index of refraction thereof upon the application of a correction signal; and electrode means (80, 82) connected to the alignment means for applying the correction signal thereto.
Claim 4
Dependent Claim
69 words
An optical disk drive according to claim 3 wherein the compensator lens comprises a laminated structure including: upper and lower spaced-apart transparent substrates (70, 72) and means (88, 90) for joining the edges of the substrates to seal the liquid crystals therebetween. transparent electrodes (80, 82) overlying the opposing faces of the substrates; and upper and lower liquid crystal alignment films (74, 76) overlying opposing faces of the electrodes.
Claim 5
Dependent Claim
58 words
An optical disk drive according to claim 4 wherein a surface profile of the lower liquid crystal alignment film is complementary to a wavefront aberration (92) in the light beam that would be reflected off the optical media of an optical disk with a protective coating having a second thickness in the absence of said compensator lens means.
Claim 6
Dependent Claim
22 words
An optical disk drive according to claim 5, wherein the surface profile of the lower liquid crystal alignment film is approximately sinusoidal.
Claim 7
Dependent Claim
29 words
An optical disk drive according to any of claims 2 to 6, wherein each electrode comprises a transparent electrode film in contact with a corresponding liquid crystal alignment film.
Claim 8
Dependent Claim
15 words
An optical disk drive according to claim 6 wherein the electrodes are made of Indium-Tin-Oxide.
Claim 9
Dependent Claim
31 words
An optical disk drive system according to any of claims 2 to 8, wherein the liquid crystals are selected from the group consisting of nematic liquid crystals and sematic liquid crystals.
Claim 10
Dependent Claim
15 words
A compensator lens means for use in the optical disk drive of any preceding claim.