Patent ID: 7978587

Claim:
An optical pickup apparatus with a single beam system, comprising: a semiconductor laser for emitting a laser light; an objective lens for irradiating the laser light emitted from the semiconductor laser as a single beam onto an optical disc; a dividing element for dividing the laser light reflected from the optical disc; and a light detector for receiving the laser light divided by the dividing element, wherein the dividing element has a region 1 , a region 2 , a region 3 , a region 4 , a region 5 , a region 6 and a region 7 ; the region 1 , the region 3 and the region 6 are line-symmetrical to the region 2 , the region 4 and the region 7 of the dividing element with respect to a center line of the dividing element; the regions 1 and 2 of the dividing element include portions which become narrower in width with the distance away from the center line, wherein the portions also become narrower in width in a light irradiated area of the dividing element with distance away from the center line, and the regions 1 and 2 are further divided in two by another line which extends in a direction perpendicular to the center line; the portion of the region 1 defines boundaries between the region 1 and regions 3 and 6 , and the portion of the region 2 defines boundaries between the region 2 and regions 4 and 7 ; the portions of the regions 1 and 2 extend beyond the light irradiated area of the dividing element, so that when the portions of the regions 1 and 2 are at a point of crossing an end of the light irradiated area of the dividing element, opposite straight edges of the portion of the region 1 are non-parallel to each other and opposite straight edges of the portion of the region 2 are non-parallel to each other; signals detected by the light detector from divided lights in the region 1 , the region 2 , the region 3 , the region 4 , the region 5 , the region 6 and the region 7 of the divided element are outputted by the light detector; and the center line extends in parallel to a track direction of the optical disc.