| 摘要 |
PROBLEM TO BE SOLVED: To easily and exactly control the quantity of a light beam by making a distance between apertures, in one direction orthogonal to the optical axis of the light beam, mutually conjugate with a first and a second apertures through a light beam branching means. SOLUTION: In this optical pickup device, an aperture A1 prescribing the diameter of a light beam made incident on an objective lens 11 shown by an arrow A1 in the figure is mutually and substantially conjugate with a second aperture A2 prescribing the diameter of a light beam made incident on the light receiving surface of a light output detector 6 shown by an arrow A2 in the figure through a slope part 27. Consequently, by controlling a light emitting output in a semiconductor laser chip 1 based on the detected light output outputted from the light output detector 6, the quantity of a light beam projected on the signal recording surface of an optical disk 101 is easily and exactly controlled. |
