Title:
OPTICAL PICKUP LENS AND OPTICAL PICKUP DEVICE
Document Type and Number:
WIPO Patent Application WO/2012/005102
Kind Code:
A1
Abstract:
With regard to a plastic optical pickup lens having a numerical aperture (NA) of at least 0.84 and provided with annular zone steps to improve temperature characteristics, an optical pickup lens and an optical pickup device are provided with which appropriately-sized light spots can be formed at depth positions of three or more information recording surfaces without producing higher-order spherical aberrations to the greatest extent possible, even when the thickness of a disk has changed. The tangent angle θ (h), the tangent angle approximation φ, and the normalized beam height h of the optical pickup lens satisfy the following conditional expression: -1 < tangent angle θ (h)- (tangent angle approximation φ × normalized beam height h) < +1. However, the tangent angle θ (h) is the tangent angle (°) when the beam height is h, the tangent angle approximation φ is the value of the angle (°) when h = 1 when each point of the tangent angle θ (h) has been obtained by linear approximation, and the normalized beam height h is the value obtained by normalizing the outermost circumference of the effective diameter of the lens to 1.
Inventors:
MIZUGUCHI, Asami (42-2 Aza Shinmei, Tazawa, Ohkuma, Watari-Cho, Watari-Gu, Miyagi 83, 〒9892383, JP)
水口 麻美 (〒83 宮城県亘理郡亘理町逢隈田沢字神明４２の２ マクセルファインテック株式会社内 Miyagi, 〒9892383, JP)
水口 麻美 (〒83 宮城県亘理郡亘理町逢隈田沢字神明４２の２ マクセルファインテック株式会社内 Miyagi, 〒9892383, JP)
Application Number:
JP2011/063962
Publication Date:
January 12, 2012
Filing Date:
June 17, 2011
Export Citation:
Assignee:
MAXELL FINETECH LTD. (42-2, Aza Shinmei Tazawa, Ohkuma, Watari-Cho, Watari-Gu, Miyagi 83, 〒9892383, JP)
マクセルファインテック株式会社 (〒83 宮城県亘理郡亘理町逢隈田沢字神明４２の２ Miyagi, 〒9892383, JP)
MIZUGUCHI, Asami (42-2 Aza Shinmei, Tazawa, Ohkuma, Watari-Cho, Watari-Gu, Miyagi 83, 〒9892383, JP)
マクセルファインテック株式会社 (〒83 宮城県亘理郡亘理町逢隈田沢字神明４２の２ Miyagi, 〒9892383, JP)
MIZUGUCHI, Asami (42-2 Aza Shinmei, Tazawa, Ohkuma, Watari-Cho, Watari-Gu, Miyagi 83, 〒9892383, JP)
International Classes:
G11B7/135; G02B13/00; G02B13/08
Attorney, Agent or Firm:
Patent Corporate Body Dai-ichi Kokusai Tokkyo Jimusho (daVinci Tamachi, 10-5 Shiba 4-chome, Minato-k, Tokyo 14, 〒1080014, JP)
Claims:
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