Sharp Kabushiki Kaisha Corporation

Koji Miyake

Toshimasa Hamada

Tetsuya Hanamoto

Shohichi Katoh

Masumi Nakamichi

Masaru Iwasaki

Takahiro Funakoshi

A light pickup device includes a light projection optical system comprising a light source which emits light, and an objective lens which condenses the light on an optical disk, a light detection optical system comprising a light detector, and a condenser lens which condenses light reflected from the optical disk on the light detector, and an adjustment optical element for coinciding a center axis of an intensity distribution of the light condensed on the optical disk by the light projection optical system with an optical axis of the objective lens.

Light pickup device with center axis and light balancing adjustment

Disclosed is a photodetector with a multilayer filter. A light-receiving substrate is mounted on a recessed portion of a ceramic stem. An electrode pad is formed on a P-type layer of the light-receiving substrate while another electrode pad is formed on an N-type layer of the light-receiving substrate. An optical multilayer filter is formed on the light-receiving substrate except the regions of the electrode pads. Further, an epoxy transparent resin is poured into the recessed portion of the stem and then cured, so that a resin portion to cover the light-receiving substrate is formed. The optical multilayer filter is formed of amorphous low refractive index films made of SiC.sub.2 and amorphous high refractive index films made of TiO.sub.2. The amorphous high and low refractive index films are alternately stacked.

Photodetector with a multilayer filter and method of producing the same

Growing community of inventors

Higashihiroshima, Japan

Koji Miyake