Pioneer Corporation

Tohoku Pioneer Corporation

Yasuo Tanahashi

Takuma Yanagisawa

Nobuyuki Satou

Toshikazu Mabuchi

A virtual image display device includes: an image forming element which forms an image to be displayed; and an optical element which reflects a light emitted from the image forming element to display a virtual image. The optical element has a concave shape opposite to a traveling direction of the light emitted from the image forming element. The light emitted from the image forming element enters the optical element without being reflected by other optical element. The image forming element is arranged in a direction substantially orthogonal to a direction of viewing the virtual image through the optical element.

Virtual image display device

There are obtainable reliable and proper tracking correction and CTC even when fluctuations occur in an irradiation position of a sub-beam in a track at the time of performing tracking correction and CTC using three beams. Five beams (a main beam, sub-beams inA and inB, and sub-beams outA and outB) are generated. Reflection beams of the five beams are received, and a differential push pull signal DPPin corresponding to the sub-beams 'in' as &#xb1; first-order beams and a differential push pull signal DPPout corresponding to the sub-beams 'out' as &#xb1; second-order beams are generated. By assigning weights to the differential push pull signals DPPin and DPPout and computing the sum of the weighted signals, a tracking error signal Ste having an amplitude value which can perform tracking correction is generated.

Optical pickup device and information recording/reproducing apparatus

The present invention makes it possible to accurately and adequately adjust the position where sub beams are shone when performing tracking correction or CTC using three beams. The invention adjusts the positions where the sub beams are shone onto the surface of an optical disc DK by changing the angle of a diffraction gratingthat is mounted inside an optical pickup. When performing adjustment, the angle of the diffraction gratingis performed in three stages: (i) rough adjustment, (ii) initial fine adjustment and (iii) continuous fine adjustment.

Growing community of inventors

Tsurugashima, Japan

Yasuo Tanahashi