Abstract: It is an object of the present invention to adjust an optical pickup without using an optical disc. An optical axis adjusting apparatus of the present invention comprises: a light receiving unit having a half mirror surface located at a position adapted to mount an optical disc and also having a photo-detector; a signal processing unit for generating a focus error signal from a detection signal outputted from the light receiving unit, and for generating another focus error signal from another detection signal outputted from a photo-detector of an optical pickup; and a control unit for controlling the posture of an actuator of an objective lens of the optical pickup and for generating adjustment signals for adjusting the optical pickup, in accordance with the focus error signal.

Abstract: It is an object of the invention to ensure the same precision as a focus adjustment based on MTF, perform an evaluation of focus adjustment on an entire image pickup surface, and reduce the size of an apparatus for performing the focus adjustment. The focus adjusting apparatus comprises a laser beam emitting section, a beam spot area measuring section, and a lens unit adjusting section. The laser beam emitting section emits a collimated laser beam to the center of the lens unit and converge the same near the center of the image pickup surface, emits a plurality of collimated laser beams at inclined angles to the central portion of the lens unit and converge them near the edges of the image pickup surface. The beam spot area measuring section measures the areas of a plurality of beam spots formed on the image pickup surface upon converging the collimated laser beams, by image-processing an output of the image pickup element.

Abstract: A light receiving unit 20A has a half mirror 20Aa and a photoreceptor device 20Af. A signal processing member 20B generates a focus error signal e from photoelectric conversion signals a, b, c and d which are outputted from the light receiving unit 20A, and further generates a focus error signal e1 from photoelectric conversion signals a1, b1, c1 and d1 which are outputted from a photoreceptor device 7 of an optical pickup P subject to adjustment. A control member 20C performs attitude control on an actuator 5A of an objective lens of the optical pickup P based on the focus error signal e, and creates data for adjusting the optical pickup P based on the focus error signal e1.