Spherical-aberration compensating element, fabricating method thereof, and optical pickup device including the same

• US 20080049172A1
• Filed: 08/24/2007
• Published: 02/28/2008
• Est. Priority Date: 08/25/2006
• Status: Abandoned Application

• Current Assignee: Funai Electric Co., Ltd. (Funai Electric Holdings Company Limited)
• Original Assignee: Funai Electric Co., Ltd. (Funai Electric Holdings Company Limited)
• Inventors: Fujii, Hitoshi, Sasabe, Mitsuyoshi, Nagashima, Kenji
• Application Number:
  US11/892,671
• Publication Number:
  US 20080049172A1
• Time in Patent Office: Days
• US Class Current: 349/92
• CPC Class Codes: G02F 1/13342 Holographic polymer dispersed liquid crystals
• CPC Class Codes: G11B 2007/0006 adapted for scanning different types of carrier, e.g. CD & DVD
• CPC Class Codes: G11B 7/1353 Diffractive elements, e.g. holograms or gratings diffraction gratings per se G02B5/18; holograms per se G02B5/32; grating systems G02B27/44
• CPC Class Codes: G11B 7/1369 Active plates, e.g. liquid crystal panels or electrostrictive elements
• CPC Class Codes: G11B 7/13925 active, e.g. controlled by electrical or mechanical means

Abstract

An optical pickup device includes at least a laser light source an objective lens, a photo detector, and a spherical-aberration compensating element. The spherical-aberration compensating element is configured so that a holographic polymer-dispersed liquid crystal formed by dispersing liquid crystal molecules in a polymer resin in a predetermined pattern is interposed between a pair of transparent substrates facing each other through transparent electrodes. Additionally, at least two or more spherical-aberration compensating elements are provided on an optical axis closer to the laser light source than the objective lens.

Claims

1. A spherical-aberration compensating element comprising:

a holographic polymer-dispersed liquid crystal formed by dispersing liquid crystal molecules in a polymer resin in a predetermined pattern is interposed between a pair of transparent substrates facing each other.

2. The spherical-aberration compensating element according to claim 1,

wherein the polymer resin and the liquid crystal have substantially the same refractive index, and

transparent electrodes disposed between the transparent substrates and the holographic polymer-dispersed liquid crystal.

3. A method of fabricating the spherical-aberration compensating element according to claim 1, the method comprising a step of disposing a compound liquid of the liquid crystal and the polymer resin between the transparent substrates and irradiating interference fringes of light on the compound liquid.

4. A method of fabricating the spherical-aberration compensating element according to claim 2, the method comprising a step of disposing a compound liquid of the liquid crystal and the polymer resin between the transparent substrates and irradiating interference fringes of light on the compound liquid.

5. An optical pickup device having the spherical-aberration compensating element according to claim 1, the device comprising:

a light source emitting light beams having wavelengths different from each other;

an objective lens focusing the light beams emitted from the light source on a recording surface of an optical recording medium; and

a photo detector receiving the light beams reflected from the recording surface,

wherein the spherical-aberration compensating element is disposed on an optical axis closer to the light source than the objective lens.

6. An optical pickup device having the spherical-aberration compensating element according to claim 2, the device comprising:

a light source emitting light beams having wavelengths different from each other;

an objective lens focusing the light beams emitted from the light source on a recording surface of an optical recording medium; and

a photo detector receiving the light beams reflected from the recording surface,

wherein the spherical-aberration compensating element is disposed on an optical axis closer to the light source than the objective lens.

7. The optical pickup device according to claim 5, wherein at least two or more spherical-aberration compensating elements are provided.

8. The optical pickup device according to claim 6, wherein at least two or more spherical-aberration compensating elements are provided.