Sony Corporation

Satoshi Kawakita

Shinji Saito

Hiroyuki Ueda

Jin Sato

Hiroyuki Sakakibara

Motoo Aiba

Kyu Kanno

Takatoshi Yamada

A diffraction element for diffracting a particular wavelength of incident optical beam includes: a base section made from a first resin and provided with a predetermined diffraction pattern; and a cover section made from a second resin and covering the diffraction pattern, wherein a rate of change of refraction index of the first resin is substantially the same as a rate of change of refraction index of the second resin in a temperature range between a first temperature and a second temperature.

Diffraction element, objective lens unit, optical pickup and optical disc apparatus

The first and second materials of the diffraction element are selected such that the first material's refraction indexes n(&#x3bb;), n(&#x3bb;) and n(&#x3bb;) for the first, second and third wavelengths &#x3bb;and &#x3bb;and the second material's refraction indexes n(&#x3bb;), n(&#x3bb;) and n(&#x3bb;) for the first, second and third wavelengths &#x3bb;and &#x3bb;satisfy one of the conditions (1) or (2).

Diffraction element, objective lens unit, optical pickup, optical disc apparatus and design method for diffraction element

Disclosed are a lens efficiently manufactured into an accurate shape at a low cost, a manufacturing method thereof, and an optical pickup using the lens. The lens includes a geometrical optics portion for converging light having been incident thereon from its light incoming plane, and two diffraction optics portions provided on the light incoming plane and a light outgoing plane of the geometrical optics portion, wherein the diffraction optics portions are made from a material different from that of the geometrical optics portion.

Lens, manufacturing method thereof, and optical pickup

Lens manufacturing method thereof, and optical pickup

Growing community of inventors

Tokyo, Japan

Satoshi Kawakita